Historic, Archive Document

Do not assume content reflects current
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United States
sj Department of
'' Agriculture

Agricultural

Research

Service

October 1986

Proceedings of the
42nd Southern Pasture
and Forage Crop
Improvement
Conference

Held at Athens, Georgia
April 15-16, 1986

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United States
Department of
Agriculture

Agricultural

Research

Service

Proceedings of the
42nd Southern Pasture
and Forage Crop
Improvement
Conference

Held at Athens, Georgia
April 15-16, 1986

Sponsored by the
Agricultural Experiment Stations
of Alabama, Arkansas, Florida, Georgia,
Kentucky, Louisiana, Mississippi,

North Carolina, Oklahoma, Puerto Rico,

South Carolina, Tennessee, Texas, and Virginia
and the

Agricultural Research Service
U.S. Department of Agriculture

The papers in this report are reproduced es-
sentially as they were supplied by the authors.
The opinions expressed are their own and do
not necessarily reflect the views of the U.S.
Department of Agriculture.

This camera copy was prepared and edited in
the office of John D. Miller, Forage and Turf
Unit, Coastal Plain Station, Tifton, GA 31793.

Copies of this report can be purchased from
National Technical Information Service, 5285
Port Royal Road, Springfield, VA 22161. ARS
has no additional copies for distribution.

As the papers were prepared in reproducible
form by the individual authors to expedite the
publishing of the proceedings, there is some
variation in type and format; however, such
variations should not distract the attention
of the reader. Queries regarding them should
be referred to authors of the specific papers.

PREFACE

These proceedings include most of the papers
and reports presented at the 42nd meeting of
the Southern Pasture and Forage Crop Improve-
ment Conference (SPFCIC) held April 15-16,

1986, at Athens, Georgia with the University
of Georgia as host. Many of the sessions and
tours were joint with the American Forage and
Grassland Council (AFGC) whose meetings con-
tinued through the morning of April 18. Infor-
mation Exchange Groups (formerly Work Groups)
met during the morning of April 15 with many
reports included later in these Proceedings.

A tour of the research plots of the Univer-
sity of Georgia and the USDA-ARS Southern
Piedmont Research Center, Watkinsville, GA,
was made that afternoon. An extensive display
of plot machinery was assembled at Watkins-
ville, A barbecue dinner at Finchum's
Phoenix Forestry Center on the University of
Georgia campus completed the day.

During the morning of April 16, five invited
speakers addressed the combined membership of
AFGG-SPFCIC. These papers are included in
the first section of these Proceedings. The
joint afternoon session ended with a business
meeting of SPFGIC. The minutes and related
matters as well as a list of Conference
Registrants are included at the end of this
report. Participants were introduced state
by state.

These Proceedings are dedicated to Dr. Glenn
W. Burton, Research Geneticist, USDA-ARS.

A brief sketch of Dr. Burton's career pre-
pared by Dr. Homer D. Wells follows.

DEDICATION

The idea of the Southern Pasture and Forage
Crop Improvement Conference (SPFCI'C) was
promulgated during 1939 and a preliminary
organizational meeting was held during the
Association of Southern Agricultural Workers

Annual Meeting February 8, 1940 at Birming-
ham, AL. The first SPFCIC meeting was held
Tifton, GA, July 23-24, 1940. More than
40 members were in attendance at this first
meeting. Many of the charter members are
deceased and all of the others, except
Glenn W. Burton, have retired from their
careers of service. Prior to our meeting
in April, Glenn completed (January 30, 1986)
his 50th year of service as a Research
Geneticist with the USDA-ARS. Thus it was
suggested and approved by the Executive
Committee of SPFCIC that the Proceedings of
the 42nd SPFCIC be dedicated to Dr. Glenn
W. Burton for his 50 years of service to ARS.

While Glenn is recognized for his outstand-
ing service to the SPFCIC beginning by co-
hosting, along with J. L. Stephens and
B. L. Southwell, the first SPFCIC and his
many other contributions to the Conference
throughout the years, we wish to call to
your attention his major contributions to
forage and turf on a worldwide basis. Glenn's
forage and turf types of bermudagrass are grown
in the tropical, subtropical and milder temper-
ate zones throughout the world. His pearl mil-
let breeding program has not only proven of
significance in forage production, but has had
a major Impact in areas of India and Africa,
where this crop serves as a major source of
grain for human nutrition. We are accustomed
to seeing Glenn always in high gear and too
busy to play; thus, we fail to realize his
dedication to sports and recreation. Glenn's
series of Tift hybrid turf bermudagrasses
developed as a sideline to his forage breed-
ing program has had a significant impact on
sportsmen of all ages and of varying degrees
of expertise. A toddler rolling on a lawn
in Atlanta, GA, and a doddering elderly man
banging a croquet ball in Palm Beach, Florida,
are both likely to be playing on one of the
bermudagrasses developed by Glenn. The be-
ginning or novice ball player in a park or
school playground throughout the South is
likely to be playing on a bermudagrass turf
planted from one of Dr. Burton's hybrids.

Also when we lay back in our easy chair to
see the world's best football players or
golfers on television, the turf that they
perform on is often a bermudagrass developed
by Glenn. Dr. Burton, for these and the many
other contributions that you have made for
the betterment of our lives, we are proud to
dedicate these Proceedings to you.

Homer D. Wells

iii

CONTENTS

Page

Invited Speakers 1

Chairman - Carl Hoveland

Forages for the Future

- Glenn W. Burton 1

The Future of Forage Quality Evaluation

- Gordon G. Marten and Neal P.

Martin 4

The Dairy Industry and Its Future

- Dave Mertens 13

Grass - The Next Cinderella Crop

- H. Allan Nation 17

The Beef Industry and Its Future

- David G. Topel 20

Breeders Research Information Exchange

Group 24

Ghairman - Gary A. Pederson

Forage Legume Breeding in Florida -
David Baltensperger , G. M. Prine,
and K. H. Quesenberry 24

Germplasm Improvement in the Mississippi
Clover Breeding Program - W. E. Knight,

M. M. Ellsbury, M. R. McLaughlin,

G. A. Pederson, R. G. Pratt, and G. L.

W ind ham 26

Breeding of Serecia Lespedeza (Leaped eza

cuneata (Dumont) G. Don.) in Alabama.

A Historical Outlook - Jorge A.

Mosjidis 30

Trefoils for the Southeast - J. F.

Pederson and C. S. Hoveland 34

A New Look at Rose Glover -

G. R. Smith 37

Extension Research Information Exchange

Group 41

Chairman - Wade Faw
The Benefits of Fescue Pasture Renewal

- James E. Standaert 41

Forage Utilization Research Information

Exchange Group 47

Chairman - David G. St. Louis

Progress of S-167 Regional Project

- G. P. Bagley 47

Yield and Quality Differences Among Gultivars
of Endophyte-free Tall Fescue -
Joe Bouton 48

Exploring the Plant-Animal Interface - Diet
Selection, Canopy Structure and Intake

Measurement Problems and Solutions
- J. R. Forwood 50

Canopy Structure Effects on Ingestive
Behavior - J. E. Moore and L. E.
Sollenberger 53

Summary of Regional Project S-156, Simulation
of Forage and Beef Production in the South-
ern Region - L. M. Thar el, M. A. Brown

and E. M. Smith 58

Appropriate Markers and Methodology for

Grazing Research - K. R. Pond, J. C. Burns,
D. S. Fisher, and R. A. Quiroz .... 62

Business Meeting and related matters .... 67

Gonference Registrants 68

Mention of trade names or companies does not
imply recommendation or endorsement by the
U. S. Department of Agriculture over others
not mentioned.

IV

FORAGES FOR THE FUTURE
Glenn W. Burton^

INTRODUCTION

Forages have contributed greatly to man's well
being for thousands of years. While yet a
hunter, he supplied most of his food and clothing
from forage-consuming animals. When domesticated,
these animals; cattle, sheep, horses, goats,
etc. ; became symbols of wealth and provided food,
clothes and power to transport burdens and till
the soil.

The first forage to be intentionally planted by
man was probably alfalfa. As early as 490 BC,
when the Medes and Persians invaded Greece,
they introduced alfalfa to feed their chariot
horses, camels, and domestic animals. Many of
the cool season grasses and clovers were brought
to the United States by the early colonists.

Most of the cultivated forages in the U.S. today
were introduced from other countries and have
been planted in the past century.

In 1979, Kunz and Purcell (1982) concluded that
more than one- third of the value created in U.S.
agriculture, was attributed directly or
indirectly to forage. They did not attempt to
evaluate the important role that forages play in
soil conservation, the reduction of erosion and
the improvement of soil fertility.

I believe the need for forages will grow. The
population explosion will see to that as people
compete with livestock for grain. It took till
1830 to put the first billion people on earth.

It took 100 years to add the second billion,

30 years to add the third, 15 years to add the
fourth, and just 10 years to add the fifth. If
population continues to increase at its present
rate, the world must feed 8 billion people by
the year 2010.

Only 5% of the earth's surface is arable, suitable
for growing crops. The best 3% is presently
feeding the world. The other 2% is producing
wood and other products needed by man. Much of
the arable land needs the protection of forages.

Forage fed beef will contain less of the excess
fat that characterizes most grain fed beef. It
will help to satisfy the growing demand for
low-fat diets.

I believe the future will see the planting and
use of more forage but the forages must be
better than those in general use today. Although
adapted sod forming perennial forages can pro-
tect erodable soil better than other plants, they
must do more. They must produce feed for live-
stock at a reasonable profit to the landowner.

The choice of forage species that can do this
will require the experience and judgement of

^Research geneticist, USDA-ARS, and Univ. of Ga.
Coastal Plain Exp. Station, Tifton, GA 31793.

plant and animal scientists working together.
Germplasm collections thought to have forage
potential must be evaluated. Certainly, the
forages chosen must be adapted to the environment,
particularly when defoliated by or for livestock.
New species may appear but most species with
forage potential have been planted in the South
many times. Their success or failure has been
influenced by the fertilization and management
that they received. Given better management,
species discarded may reappear. Correcting
their genetic weaknesses must be the job of the
forage breeder with the help of scientists from
other disciplines as needed. A description of
some of the major tasks and suggested procedures
follows :

Future forages must be dependable. A forage that
fails because of mismanagement or adverse weather
will force its user to sell his animals at a loss
or pay too much for replacement feeds. Perennials
that survive will be more dependable than annuals
because they are less dependent on weather and
management to produce seed and become established
each year. Crabgrass , Digitarls sanguinalls, is
a very good warm season pasture grass. A south
Georgia farmer who successfully used it for
several years, planted Coastal bermudagrass after
he failed to get grazable stands of crabgrass.

Perslstance is probably the best test of dependa-
bility. Many grass and legume species have been
planted in the South. Only three grasses, tall
fescue, Festuca arundlnacea ; Pensacola bahiagrass,
P asp alum notatum; and bermudagrass, Cynodon spp.,
pass this test. These grasses are the base for
most improved pastures and may continue to be for
some time. As long as they are the base, they
warrant the greatest improvement effort.

Lack of dependability is the greatest weakness of
the many legumes that have been planted in
perennial pastures across the years. Crimson
clover, Trif ollum Incarnatum, that once occupied
a million acres in Georgia, has largely dis-
appeared. Adverse weather and mismanagement that
failed to produce a seed crop every spring and
establish a stand every fall were contributing
factors. But lack of dependability and failure
to produce the dependable results obtained from
a dependable grass plus nitrogen caused farmers
to lose interest. As legume breeders search for
better species and strive to improve the best
they have, dependability must be one of their
major objectives.

Increasing the tolerance of grasses and legumes
to stresses such as drought and cold will improve
their dependability. Such progress in both areas
has been demonstrated in our bermudagrass
breeding. Coastal bermuda, about twice as pro-
ductive as common bermudagrass in a good year,
produced six times more forage in a very dry year.
Tifton 44 is dependable farther north than
Coastal, thanks to its hardiness genes from a
common bermuda found in Berlin, Germany. Germ-
plasm collections and better screens for drought
and cold stress will be needed to make future
forages more cold and drought tolerant.

1

Future forages must be more resistant to
diseases, insects, and weeds. Improving their
resistance will also make them more dependable.

Because animals eat about the same amount of
forage each day, future forages to be grazed
will have a more uniform growth rate over a
longer period of time than the best we have
today. For processing into hay or silage, rapid
seasonal growth that gives a high yield of high
dry matter forage will be preferred.

Costs of establishment and production must be
kept low for forages to compete with other land
uses. One of the best ways to do this is to
develop cultivars of adapted forages that can
produce more forage with the same inputs. Such
cultivars must be more efficient in recovering
or utilizing one or more of the growth factors
(water, CO2, light, temperature, and plant
nutrients). A number of plant breeding methods
are available to do this.

Synthetic Cultivars. The method most frequently
used in improving forages is the development of
synthetics. Superior plants screened from germ-
plasm collections are usually grouped together
with or without testing for compatibility.

Usually they flower at about the same time and
have similar important traits such as disease
resistance. The parent clones are frequently
retained to continually supply breeders seed and
prevent drift. By the time the synthetic is
increased enough to reach the consumer (syn 4 or
later), most of the heterosis that might have
been in syn 1 has been lost.

Mass Selection. Mass selection, the oldest plant
breeding method, can be effective for improving
characteristics with a high heritability .

Florida 77 alfalfa (Medlcago satlva) the product
of recurrent mass selection, is proof of its
power (Horner and Ruelke, 1980). A good screen,
an effective system for intermating selected
plants and time are the ingredients required for
success. Earl Horner, University of Florida
agronomist, began a program to improve the
persistence of alfalfa at Gainesville, Fla. in
1950. A consistant adverse environment that
eliminated most plants in 2 to 3 years supplied
the screen. Bees intermated the surviving
plants, seed from which was used to plant the
next cycle. Persistence had been significantly
improved by cycle 6, released as Florida 66 in
1966 but the spotted aphid in the west prevented
commercial seed production. An effective screen
for spotted aphid resistance plus effective
intermating by bees in 3 cycles increased aphid
resistance from 0.005% to the 71.5% in an
improved cultivar named Florida 77.

Recurrent Restricted Phenotypic Selection. A

better method of increasing the yield and
efficiency of a forage is recurrent restricted
phenotypic selection (RRPS) that is four times
more efficient than mass selection (Burton, 1974).
In replicated seeded plots clipped five times per
year, cycle 9 of RRPS has yielded 47% more dry
matter than the Pensacola bahia check (Burton,
1985).

Wlien we started to use mass selection to increase
the forage yields of Pensacola bahiagrass in
1960, we did not expect much progress. The
correlation between yields of spaced plants and
their clonally established plots was only 0.4.

We expected to need 2 to 3 years per cycle. We
decided, however, to grow 1000 spaced plants,
select the top 5 plants in each 25 plant block
and intermate those 200 selections for the next
cycle. During the past 25 years, we have modi-
fied procedures to Improve the precision of our
screen for yield and our intermating system.

Today these eight modifications of mass selection
called 'restrictions' enable us to complete one
cycle of RRPS per year and increase the mean
yield of the space planted population over 16%
per cycle through cycle 9 (Burton, 1974, 1985).
With slight modifications, I believe RRPS can be
a very effective method for increasing the yield
of many cross-pollinated forages such as tall
fescue, Festuca arundlnaceae.

F- Hybrids. Good F^^ hybrids can Increase forage
yields 20 to 100%. The challenge is developing
methods to put the F hybrid on the farm. The
vegetatively propagated bermudagrass F^ hybrids
such as Coastal, Tifton 44, and Tifton 78 have
doubled dry matter yields when compared with the
common type. Breeding such vegetatively propa-
gated hybrids requires less work and time than
breeding those propagated by seed. If they, like
Tifton 78 bermudagrass, can be established by
disking into moist soil freshly mowed tops, the
cost and time required for establishment can be
less than for seed propagated forages.

Gahi 1 pearl millet, a first generation chance
hybrid, gave the cattlemen the benefits of
hybrid vigor long before other methods of pro-
ducing commercial F hybrid seed (Burton and
Powell, 1968) were available. Seed for Gahi 1
were produced by harvesting all seed from a field
planted to a mixture of equal quantities of pure
live seeds of four inbreds that produced high
yielding hybrids in all combinations. This seed
contained 75% of the six possible Fj^ hybrids
which planted in the field crowded out the other
25% of seifs and sibs and yielded as well as the
doublecross of the 4 Inbred lines - 50% more than
the cattail check. This method has also been
successfully used to Increase forage yields of
sudangrass. Sorghum vulgare sudanense .

Cytoplasmic male sterility (cms) (in those species
where it has been found) offers one of the best
mechanisms for producing F^ hybrid seed. Hybrid
forage sorghums and pearl millets such as Gahi 3
and Tifleaf 1 are seed propagated cms F hybrids.

I believe the future will see cms F^ hybrids of
other forages on the farm.

The future will most certainly seed a greater use
of apomlctic hybrids. These seed propagated
hybrids breeding true and maintaining their
desirable traits through succeeding generations
will be a boon to the livestock industry.

Higgins buffelgrass, Cenchrus clllarls , is an
apomlctic F^^ hybrid bred at College Station,

Texas (Taliaferro and Bashaw, 1966).

2

To increase yields of animal products and reduce
production costs, yields must be increased with-
out reducing quality. The quality of a forage
is finally determined by the performance,
usually average daily gains of livestock
consuming it. Although digestibility, intake and
utilization are characteristics that determine
forage quality, digestibility is generally the
most important. Digestibility usually correlates
well with ADGs and can be measured with
laboratory tests such as the vitro dry matter
digestibility procedure (IVDMD) . The positive
correlation that usually exists between
digestibility and Intake, permits some selection
for intake with the IVDMD analysis or the
near- inf rated spectroscopy (NIRS) analytical
tests. However, similar rapid inexpensive tests
that might be used to screen forages for Intake
and utilization would be a boon to the forage
breeder.

The quality of forages and the gains of livestock
consuming them can be improved by removing
inclusions that affect animal performance
adversely. The asexual fungal endophyte,
Acremonium coenaphlalum, is such an Inclusion.

The association of this endophyte with tall
fescue toxicosis is one of the most significant
forage discoveries of this century (Hoveland,
et al, 1983). Research underway at several
research stations in the South suggests that
each 10% increase in tall fescue tillers
infested with the endophyte reduces ADGs 0.1 lb.
The endophyte is seed borne in tall fescue but
usually dies in seed stored for 1 to 2 years
after harvest. Research to date indicates that
the endophyte does not spread from plant to
plant.

..There is evidence to indicate that plants
infested with the endophyte are more resistant to
the attack of certain insects. Thus removing
the endophyte to improve the quality of tall
fescue, may reduce its excellent adaptability.

Evaluation. Future cultivars should be
thoroughly tested before releasing them to live-
stock farmers. Replicated small plot tests
designed to measure seasonal distribution and
total yield of forage plus IVDMD analyses of all
forage harvested from each entry will help to
separate the best from the better entries
included in a test. The one or two with the
best agronomic and small plot record should be
included in feeding and grazing trials;
preferably with the kind of animals that will
finally use them. Animal scientists should help
to conduct such tests and Ideally should be a
part of every forage team.

Distribution and Management. To make their
maximum contribution to the livestock industry,
the future forages must be grown wherever they
are superior to other forages. With their
distribution should go a management "package"
that will enable them to reach their full
potential. Crop Improvement Associations can
often help with the increase and distribution of
new cultivars. Exclusive release to one private
company may be desirable, especially if seed

must be produced at great distances from the area
of use.

Literature Cited

Burton, G. W. 1974. Recurrent restricted

phenotypic selection increases forage yields
of Pensacola bahiagrass. Crop Sci. 14:831-835.

Burton, G. W. 1985. Spaced-plant-population-
progress test. Crop Sci. 25:63-65.

Burton, G. W. and J. B. Powell. 1968. Pearl

millet breeding and cytogenetics. In Advances
in Agronomy, Vol. 20, pp. 49-89, Academic
Press, New York.

Horner, E. S. and 0. C. Ruelke. 1980. Florida 77
alfalfa and recommended management practices
for its production. Univ. of Fla. Cir. S-271.

Hoveland, C. S., S. P. Schmid, C. C. King, Jr.,

J. W. Odom, E. M. Clark, J. A. McGuire, L. A.
Smith, H. W. Grimes, and J. L. Holliman. 1983.
Steer performance and association of
Acremonulm coenophialum fungal endophyte.

Agron. J. 75:821-824.

Kunz, Janice J. and Joseph C. Purcell. 1982.
Value added (created) in United States
Agriculture IR-6 Information Report No. 61.
Interregional Cooperative Publication of the
State Agriculture Experiment Stations, July.

Taliaferro, C. M. and E. C. Bashaw. 1966.

Inheritance and control of obligate apomixis
in breeding buffelgrass, Pennlsetum cillare.
Crop Sci. 6:473-476.

3

THE FUTURE OF FORAGE QUALITY EVALUATION

1 2
Gordon C. Marten and Neal P. Martin

INTRODUCTION

"Forage quality" and "feeding value" of
forages are synonjnnous terms that must be
broken down into sub-factors if we hope to
develop and understand evaluation methods.
Because animal performance is the ultimate
expression of true feeding value. Marten
(1985) placed it at the top of a list of
factors that contribute to forage quality
(see Figure 1). For purposes of discussion
of the future of forage quality evaluation,
we will concentrate on the two universal
sub-factors that contribute to potential
forage feeding value, namely potential
nutritive value (especially energy nutrients
and their digestibility) and potential
intake by the ruminant animal. The degree
of digestibility or of available energy from
forages can be expressed by several terms
that are all highly related. Among these
are total digestible nutrients (TDN) ,
digestible dry matter (DDM) , digestible
organic matter (DOM) , and digestible energy
(DE) . We will select DDM because it is
currently being used in hay quality
standards and in many research and extension
programs .

Fonnesbeck (1985) also featured voluntary
intake and digestion when he recently listed
the factors that influence alfalfa hay
quality (see Figure 2). Therefore, we will
consider mostly these two items as we look
to the future of forage quality evaluation.

LABORATORY METHODS FOR EVALUATION OF
FORAGE QUALITY

There are essentially four categories of
laboratory methods for evaluation of
quality of all types of forages. Among
these are the following:

1. "See-Smell-Touch" (organoleptic);

2. "Protein-Fiber-Mineral" (chemical);

3. "Tube-Bag-Bunny" (microbial or

biological) ;

4. "Grind-Sieve-Bombard" (physical).

These laboratory methods are discussed in
detail in review articles by Barnes and
Marten (1979) and Marten (1981). The

Research Agronomist, U.S. Department of
Agriculture, Agricultural Research Service,
2University of Minnesota, St. Paul, MN.
Extension Agronomist, University of
Minnesota, St. Paul, MN.

organoleptic methods are as old as history;
they must still be relied upon to detect
contamination of forages with foreign
materials, toxic weeds, molds, etc. The Van
Soest systems of fibrous feed analysis have
become primarj? standards for chemical evalu-
ation of forages throughout the world. Of
special interest to us in this discussion are
acid detergent fiber (ADF) as a predictor of
digestibility (especially for alfalfa and
temperate grasses) and neutral detergent fiber
(NDF) as a predictor of intake potential of
forages and of the proportion of grass in
legume-grass mixtures. Concentrations of
crude protein, specific minerals, and water in
forages also are of major interest because the
former two are required nutrients and the
latter often indicates the conditions and type
of forage curing and preservation. Moisture
concentration must also be known in order for
us to calculate nutrient concentration on a
dry matter basis.

The laboratory method usually considered to be
superior for the prediction of ruminant in
vivo (in the animal) digestibility of forages
is the ^ vitro (in the test tube) rumen
fermentation technique. This method uses
microbe-rich fluid taken from a hole in a
ruminant's rumen to digest ground forages
during incubation in the laboratory. This
"artificial cow" approach is often used in
research labs, but the procedure is costly
and difficult to standardize in non-research
situations. Also, the "nylon bag" approach,
whereby small cloth bags containing ground
forages are suspended in a cow's or sheep's
rumen, is difficult to standardize and limit-
ed in the number of samples that can be
efficiently analyzed. Recent evidence that
very potent fungal enzymes (cellulases) that
mimic the action of rumen microbes can be
cultured in the laboratory may provide a good
alternative for researchers who do not have
access to live animals. However, a limited
number of samples can be analyzed per unit
time with these as well as with conventional
chemical approaches.

The "bunny methods" (small animal bioassays)
vary in their applicability to forage species.
For example, rabbits can provide a good eval-
uation of relative quality of alfalfa harvest-
ed at a wide range of growth stages, but they
do not usually successfully differentiate
among grasses of varying quality. Again, small
animal bioassays are quite costly and do not
allow analysis of large numbers of samples on
a routine basis.

The amount of electrical energy required to
grind forage samples has at times been well
associated with digestibility as well as in-
take potential of forages that have a wide
range of quality. So too have the sieving
properties of soaked, unchopped grasses and
legumes. However, these methods are difficult
to standardize, do not work for all forages.

4

and do not apply to routine assessment of
large numbers of samples.

Without question, the physical method that
holds the greatest promise for routine
measurement of nearly all facets of forage
quality is near infrared reflectance spec-
troscopy (NIRS) . This procedure, whereby
radiation in the near infrared region of
the electromagnetic spectrum is "bombarded"
on finely ground samples of dried forages,
and whereby the reflected light is captured
and analyzed by a computer to indicate
chemical composition and associated forage
quality traits, has revolutionized forage
quality evaluation.

NEAR INFRARED REFLECTANCE SPECTROSCOPY

PHYSICAL MEANS TO ORGANOLEPTIC, CHEMICAL, AND
MICROBIAL ENDS

The question is, can we "bombard" to do it
all? The answer is, we're getting close!
Because NIRS can provide the fast, precise,
and outlier information sought by plant
breeders, plant breeding is the uppermost area
of research for which this new technology can
be recommended without further development
(Marten et al. , 1985). NIRS has also already
proved of great value for routine assessment
of chemical composition, digestibility, and
other quality traits (including sometimes
intake) of forages needed by researchers
concerned with forage crop management, forage
physiology, and ruminant nutrition. In
addition, extension specialists in several
states have successfully used NIRS to
determine crude protein, heat-damaged protein,
several fiber traits, dry matter, digestibil-
ity, and minerals in hay, dried hay-crop
silage, dried corn silage and dried
high-moisture grain used in ruminant animal
ration balancing (Adams, 1984; Martin et al. ,
1984; Rohweder, 1984). Mobile NIRS systems
have further been used in extension programs
and in private testing programs to aid buyers
and sellers of hay in establishing equitable
prices at auctions.

In the future, scientists hope to standardize
NIRS for analysis of feed ingredients,
concentrate mixtures or forage-concentrate
mixtures, undried high-moisture feedstuffs,
specific plant species composition of mixed
forages, and micro components of forages (such
as vitamins, toxins, and molds).

WHAT DOES ACCURATE AND TIMELY EVALUATION OF
FORAGE QUALITY MEAN TO THE PRODUCER?

The Relative Feed Value Concept

In 1976, a task force of scientists cooperated
with the American Forage and Grassland Council
(AFGC) to develop a new hay grading and forage
evaluation system based on chemical analysis

to predict both digestible dry matter (DDM) and
dry matter intake (DMI). Acid detergent
fiber (ADF) was used to predict DDM and neutral
detergent fiber (NDF) was used to predict DMI.
These two measures were then used to calculate
digestible dry matter intake which, in turn,
was converted to a scale that would allow a
mid-to-full-bloom alfalfa hay that contained
40% headed grass to have a "relative feed
value" (RFV) of about 100. Later, this
grading system was slightly modified (Jorgensen
et al. , 1985) to provide the grades and
descriptions given in Table 1. The proposed
standards were complex and received only mixed
support from. Industry; however, at least parts
of these standards are used routinely today
in extension programs in Wisconsin, Illinois,
Minnesota, Oregon, Washington, Idaho, Utah,
and other states.

In 1982, a group of scientists representing
AFGC and hay industry representatives from
throughout the nation met to establish a U.S.
Alfalfa Hay Quality Committee. In 1983, common
simplified standards wqre accepted, which have
come to be known as the "National Alfalfa Hay
Testing Association Standards".

The National Alfalfa Hay Testing Association
Standards

The new standards that were devised by the U.S.
Alfalfa Hay Quality Committee to be applied
nationally include use of ADF (to calculate
estimated digestible drj' matter; EDDM) , crude
protein (CP), and dry matter (DM). The commit-
tee also allows nutritionists to calculate
digestible energy from EDDM via local equations
and suggests that visual and other organoleptic
criteria (to vary by area) be included. The
ultimate goal of the new association is to
foster a nationally uniform marketing system
that will permit hay to be priced on the basis
of its feeding value. Both hay buyers and
sellers will receive more accurate nutritional
information in this equitable system. Live-
stock feeders will also be able to put the
nutritional information to use as they balance
rations .

The Subcommittee on Laboratory Certification
of the original U.S. Alfalfa Hay Quality
Committee issued a publication (1984) entitled
"Hay Testing Laboratory Certification Manual"
that outlines sampling, laboratory sample
preparation and analyses, EDDM equations, NIRS
applicability to predicting the chemical com-
ponents needed for hay testing, and statistical
information (data analyses and an outlier test)
needed for laboratories to participate in a
voluntary certification program jointly ad-
ministered by the National Hay Association and
the AFGC.

Other Evaluation Of Forage Quality For
Producers

Various extension and industry programs

5

feature their own individual standards for
estimating feeding value of forages used in
producer programs. These usually contain
measures of CP, some form of available
energy, and mineral and dry matter concen-
trations. For example, the University of
Florida program relies on a "Quality Index"
(QI) to express intake of digestible energy
as a multiple of the total digestible
nutrient (TDN) maintenance requirement
(Moore et al. , 1984). In this program, NIRS
is used to predict CP and NDF as percentages
of DM, and vitro organic matter digestion
(IVOMD) . Then appropriate formulas are used
to convert NDF and IVOMD to TDN as a per-
centage of DM, as well as to calculate QI.

The QI was specifically developed for Florida
tropical grass hays because the hay standards
discussed earlier are based on temperate
perennial forages and are not applicable to
tropical grasses. It estimates ultimately the
expected voluntary intake of TDN if the forage
is fed free-choice and alone. Quality Index
is expressed as a multiple of the animal's TDN
requirement for maintenance, so that a QI of
1.0 indicates that the forage would support
maintenance of a dry beef cow. Instead of a
hay grade, QI assigns a numerical value to a
forage which estimates whether it meets the
TDN intake requirements of a specific class of
animal.

The Hay Auction

A number of states are regularly using mobile
NIRS systems to evaluate quality of hay at
local or regional auctions. The usual
response to this program has been an improve-
ment in prices for top quality hay and a
substantial increase in subsequent testing and
selling of hay based on quality. For example,
the number of auctions in Wisconsin at which
hay was tested for quality rose from one to 98
during the four-year period after NIRS tests
first became available (Figure 3; Rohweder and
Vilstrup, 1985). The average price for hay
sold by grade (based on RFV) at these auctions
ranged from $117 per ton for "prime" to $68 or
less per ton for grades 3 and lower (Figure 4;
Rohweder and Vilstrup, 1985). The correlation
between price and RFV was r=0.58, and sellers
received $1.05 for each point increase in RFV
for stages of hay maturation earlier than full
bloom (greater than grade 3). Similarly, in
Minnesota auctions, hay prices ranged from a
high of up to $132 per ton for prime grade to
$52 per ton or less for grades 3 and lower
(Linn, 1985); the correlation between price
and RFV was r=0.80.

Testing will not always raise the price of hay
sold, and it may sometimes result in lower
prices (Bushnell, 1985); however, it will make
hay prices more equitable to both buyer and
seller.

The Educated Management Decision, Balanced
Ration, And Resulting Profit

The objective in management decisions regard-
ing forage utilization is to determine the
quality and quantity of forage categories
available and then to use the various cate-
gories in feeding animals relative to their
needs to insure maximum profits. If a farmer
had two hay lots, one that tested 144 RFV and
another that tested 100 RFV, he could expect
varying animal response and profit depending
upon how he used these hays relative to the
production potential of individual cows in
his herd (assuming sufficient protein and
energy supplements also were fed). If we
assume ;

Case A-the cow has genetic potential to

produce 15,000 lb. of milk per year; and

Case B-the cow has genetic potential to

produce 20,000 lb. of milk per year;
then feeding the 100 RFV hay would be wise in
case A because the cow's nutritional needs
could be met, and she would produce essential-
ly no more by feeding the 144 RFV hay; however,
feeding the 144 RFV hay would be wise in case
B because this cow's nutritional needs could
not be met by rations containing the 100 RFV
hay (she would produce only 15,000 lb. of milk
per year if fed it), and she requires the 144
RFV hay to produce her genetic potential of
20,000 lb. Therefore, if the farmer has more
144 RFV hay than is required for his 20,000-
Ib-pctential cows, he should sell the hay at
an equitable price to his neighbor who has
20,000-lb-potential cows that can benefit from
it rather than feeding it to lower-producing
animals. This recommendation is based on our
assumption that we currently have more 20,000-
lb-potential COW'S in production systems than
there is 144 RFV hay to meet their needs.

The farmer who participates in a forage test-
ing program will ask new questions that will
lead to increased production efficiency. An
example is the farmer at a recent Minnesota
hay auction (NIRS quality-tested) who found
that his hay had a RFV of 120, but CP of only
11%. Upon the farmer's questioning of the
results, the hay was examined and determined
to be mostly very leafy orchardgrass that had
not been fertilized with nitrogen. The farmer
was instructed by the extension specialist that
N fertilizer would have increased both the CP
concentration and yield of his hay crop. We
predict that next year this farmer will either
fertilize his hay field with N or renovate to
establish legumes to furnish hay that meets
both the protein needs and the RFV needs of
cattle owned by local hay buyers.

Extension specialists at the University of
Wisconsin have reported considerable improve-
ments in farmers' understanding of forage
quality due to participation in a NIRS analysis
program (Table 2). Positive actions included
40% more use of ration balancing for dairy

6

herds and 84% increased crop management
modification. Increased profits were
reported in 87% of the cases. Milk produc-
tion per cow in herds of farmers who
participated in the NIRS forage analysis
program usually increased; 88% of the herds
experienced at least 800 lb more milk per
cow per year, and 33% of the herds experi-
enced at least 2,400 lb more milk per cow
(Table 3).

Wisconsin workers also reported improvements
in efficiency of dairy ration balancing
programs associated with tests of forage
quality enabled by NIRS (Table 4) . Mean
increased profit per cow in 100 herds was
about $100 per year.

Yet to be determined is which quality levels
of hay and other forages are so low that
they prevent economic feed use for specific
classes of ruminants. Often forage growers
don't know their production cost, or if they
do it is on a per acre rather than a per ton
basis. To evaluate alternative uses for
forage crops, the production cost per ton is
needed. Then one can calculate the feed
value per ton (via forage quality testing)
and ultimately the return per ton. In this
way, the farmer can determine whether he
will save by purchasing less concentrates
and whether he will profit by feeding vs.
selling his hay.

Rohweder (1985) listed the following impacts
that resulted from NIRS analysis of forage
quality by dairy farmers: (1) increased
awareness of forage quality; (2) improved
crop and animal management; (3) more
accurate, precise, rapid, low cost, and
accessible forage analyses; (4) more precise
ration balancing schemes; and (5) increased
profits. He stated that "NIRS analysis has
helped farmers take charge in these changing
times". That sums up the present for pro-
gressive dairy farmers but, the future of

forage quality evaluation rests in the
creative extension of present and future
testing procedures and information to all
ruminant animal production systems because
all of these systems rely heavily on forage
as the primary feed.

SUMMARY

"Forage quality" encompasses numerous traits,
but two universal factors are nutritive
value, which requires some expression of
digestible energy, and potential intake by
the ruminant animal. Four categories of
laboratory methods have been developed to
evaluate forage quality. A revolutionary
new procedure that has great potential for
analyzing chemical composition and associated
forage quality traits is near infrared re-
flectance spectroscopy (NIRS).

The concept of relative feed value, which in-
cludes expressions of both digestible dry
matter and dry matter intake, has been
effectively used in forage evaluation, hay
marketing, and ration balancing systems. New
National Alfalfa Hay Testing Association
Standards require expressions of estimated
digestible dry matter, crude protein, and dry
matter as minimum values. NIRS has been
accurately used in essentially all of the current
forage evaluation schemes and has allowed
auctioning of hay on the basis of its feed
value.

Educated management decisions depend on know-
ledge of quality of forages being fed to
different classes of livestock. Those
producers who have become knowledgeable about
forage quality and testing Invariably develop
more efficient forage production and utiliza-
tion programs and increase their profits.

The future of forage quality evaluation depends
on the creative extension of present and future
testing procedures and information to all types
of ruminant animal production systems.

Literature Cited

Adams, R.S. 1984. Use of NIR, a rapid com-
puterized forage testing method, p. 15-19
In Proc. 9th Annual Minnesota Forage Day.
Minnesota Forage and Grassl. Coun. , St.

Paul.

Ballweg, M.J., D.A. Rohweder, and W.T. Howard.
1985. Personal communication. University
of Wisconsin, Madison (from presentation
by Rohweder at 1985 Amer. Soc. Agron.
Symposium on Transfer of NIRS Technology).

Barnes, R.F., and G.C. Marten. 1979. Recent
developments in predicting forage quality.

J. Anlm. Sci. 48:1554-1561.

Bushnell, J.L. 1985. Hay marketing. Results
of questionaire reported at the Invita-
tional ECOP Workshop on NIRS, November
13-15, 1985, Madison,

Wisconsin.

Fonnesbeck, P.V. 1985. Personal communica-
tion, Utah State University, Logan (from
presentation at 1985 Amer. Soc. Agron.
symposium on National Alfalfa Hay
Standards) .

Jorgensen, N.A. , W.T. Howard, and D.A.

Rohweder. 1985. Forage analysis, terms,
measurements, usage. From paper given at
the Invitational ECOP Workshop on NIRS,
November 13-15, 1985, Madison, Wisconsin.

Linn, J. 1985. Four county forage councils
sponsor hay auction, p. 3 and 5. In
Minnesota Forage UPDATE, Vol. X, NO. 2,
spring, 1985. Minnesota Forage and
Grassl. Coun., St. Paul.

7

Marten, G.C. 1981. Chemical, in vitro, and
nylon bag procedures for evaluating
forage in the USA. p. 39-55. Forage
Evaluation: Concepts and Techniques.

Proceedings of a Workshop held in
Armidale, New South Wales, Australia in
November, 1980. CSIRO and American
Forage and Crassl. Coun.

Marten, C.C. 1985. Factors influencing feed-
ing value and effective utilization of
forage for animal production, p. 52-58 ^
Papers for Plenary Sessions, XV Interna-
tional Grassland Congress, Kyoto, Japan.

Marten, G.C., J.S. Shenk, and F.E. Barton II,
editors. 1985. Near infrared reflectance
spectroscopy (NIRS): Analysis of forage
quality, U.S. Department of Agriculture,
Agriculture Handbook No. 643, 96 p.

Martin, N.P,, D.A. Schriever, G.C. Marten, and
F.R. Ehle. 1984. Use of near infrared
reflectance spectroscopy (NIRS) to analyze
forage quality of alfalfa grower samples,
p. 223-227. ^ Proc. 1984 Forage and

Crassl. Conf . , American Forage and Crassl.
Coun. , Lexington, Kentucky.

Moore, J.E., W.E. Kunkle, K.A. Bjorndal, R.S.
Sand, C.C. Chambliss, and P. Mis levy.

1984, Extension forage testing program
utilizing near infrared reflectance spec-
troscopy. p. 41-52. ^11 Proc. 1984 Forage

and Crassl. Conf., American Forage and
Crassl. Coun, , Lexington, Kentucky.

Rohweder, D.A. 1984. Wisconsin's NIR and hay

marketing projects a progress report, p.

1-12. Proc. Wisconsin Forage Coun. 8th
Forage Production and Use Symposium, Wis-
consin Forage Coun. , Madison.

Rohweder, D.A. 1985. Personal communication.
University of Wisconsin, Madison (from
presentation at 1985 Amer. Soc. Agron.
S3niiposium on Transfer of NIRS Technology) .

Rohweder, D.A. , and R. Vilstrup. 1985. Pro-
gress Report: Quality Tested Hay Auctions

1985-86. University of Wisconsin,

Madison.

Subcommittee on Laboratory Certification of
the U.S. Alfalfa Hay Quality Committee.
1984. Hay Testing Laboratory Certifica-
tion Manual, Public. No. 2. National Hay
Assoc, and AFGC. (available from H.D.
Gates, Jr., The National Alfalfa Hay
Testing Association, P.O. Box 1059,
Jackson, MI 49204.

8

Figure 1. Plant and animal factors that influence feeding value (quality) of
forages. From Marten (1985).

ALFALFA

VARIETIES

CLIMATE

i

AGRONOMIC

PRACTICES

HARVESTING PROCESSES

I

M CHEMICAL COMPOSITION v

/ \

VOLUNTARY ^ POST-HARVEST
INTAKE- PROCESS I NG

DIGESTION

QUALITY EVALUATION

*

ANIMAL PRODUCTION

Figure 2. Factors that influence alfalfa hay quality. From Fonnesbeck (1985).

9

Number

of

Auctions

Figure

Dollars

fwr

Ton

Figure

Growth during four years of Wisconsin auctions at which hay quality
was tested by NIRS (Rohweder and Vilstrup, 1985).

4. Average price per ton of hay sold on a relative feed value (grade)

basis in two years at Wisconsin auctions (Rohweder and Vilstrup, 1985).

10

Table 1. Market Hay Grades for legumes, legume-grass mixtures, and grasses AFGC

Hay Marketing Task Force ("A continuum from^legume pre-bloom to grass
headed and/or heavily weathered forage"). —

Description

Grade

Species
and stage

CP

ADF

NDF

-% dry wt-

DDM

RFV

Prime

Leg.-PBl

>19

<31

<40

>65

>143

1

Leg.-EBl, 20%
grass-V

17-19

31-35

40-46

62-65

127-143

2

Leg. -MB 1, 30%
grass-EH

14-16

36-40

47-53

58-61

114-126

98-113-'

3

Leg. -FBI, 40%
grass-Head

11-13

41-42

54-60

56-57

4

Leg. -FBI, 50%
grass-Head

8-10

43-45

61-65

53-55

86-97

Fair

6

Grass-Head, and/or
Rain Damaged
Sample

<8

>45

>65

<53

<86

Q /

~ .Description adopted by U.S. Alfalfa Hay Quality Committee.

- PBl=Pre-bloom, EBl=Early-Bloom, MBl=Mid-bloom, FBl=Mid-to-full-bloom,
V=Vegetative, EH=Early-Head .

-'Reference hay, mid-to-full-bloom alfalfa, as RFV=100.

Adapted from Jorgensen et al. (1985).

Table 2. Improvements in Farmers' Understanding of Forage Quality Due
NIRS Analysis Program (Ballweg, Rohweder and Howard, 1985).

Factor that Percentage increase in

was improved comprehension or action

Comprehension of forage dry matter
& crude protein

95

Knowledge of effect of dry matter on
silage quality and of cutting
schedules on forage quality and
yield

74

Comprehension of acid detergent fiber
as a predictor of digestibility
and of neutral detergent fiber
as a predictor of intake

40

Crop management practices

84

Use of ration balancing

40

Increase in net profit

87

Table 3. Extent of Improvement in Milk Production Per Cow (Increase in Rolling

Herd Average) in Wisconsin Due to Use of a NIRS Forage Analysis Program
(Ballweg, Rohweder and Howard, 1985):

Increase in milk Percentage of herds

(Ib/cow/year) that showed response

None

10

800

40

1600

15

2400

18

3200

15

Table 4. Improvements in Efficiency of Dairy Ration Balancing Programs Associated
with Tests of Forage Quality in Wisconsin (Ballweg, Rohweder, and Howard,
(1985).

Improvement

Iraprovement

pre-NIRS when

post-NIRS when

crude protein

digestibility

Efficiency

was emphasized

& intake were

Factor

(1978)

emphasized (1984)

Increased milk/cow

67%

96%

Decreased cost of purchased feed

70%

83%

Decreased amount of grain fed

14%

68%

Increased amount of grain fed

12%

32%

Increased profit/cow

$80

$100

Increased profit from 100 herds

—

$500,000/yr

12

THE DAIRY INDUSTRY AND ITS FUTURE
D.R. Mertens^

INTRODUCTION

Current State of the Industry: The dairy industry
is facing a period of tremendous change. Milk
production has exceeded demand for many years;
however, the federal government has recently
decided not to maintain the status quo by
purchasing the excess milk produced. It is
clear that the long term solution for stabi-
lizing the industry is to balance milk pro-
duction with milk demand. Many approaches to
the problem of production/demand imbalances have
been developed. Only a few comments about the
industry-wide dilemma will be given. The
primary focus of this presentation will be the
potential role that forage production and use
can play in the survival of individual dairy
farms .

In many ways, dairy farmers are victims of their
own success. Since the late 1970's dairy
farming has been a bright spot in the agri-
cultural income sector. Profitable dairy
enterprise budgets and monthly income generation
led many lenders to encourage new farmers to
establish dairies as a means of handling large
debt loads. Many established dairymen expanded
dairy operations to accommodate cash flow short-
falls associated with increased capital
expenditures. While the number of dairy farms
decreased, the annual decline in cow numbers
stopped in 1979. Increased cow numbers combined
with increased production per cow has resulted
in excess milk production. It is clear that the
dairy industry's ability to produce milk can and
does exceed demand. Reducing the price of milk
will cause economic forces to bring production
and demand into balance. However, this will not
be accomplished without suffering by both
efficient and inefficient producers.

An alternative solution is to stimulate demand.
Dairy farmers have been encouraged to stimulate
demand via promotion and product development.
Although increasing demand is a laudable goal,
the gains appear to be small with long-term
payoffs. There is an inelasticity in food
demand associated with the inelasticity of the
human stomach. Dairy product consumption can
increase only at the expense of other food
items. Since 1970, dairy products have com-
prised a relatively stable 20 to 24% of American
food consumption. It appears the major increase
in demand will be associated with increases in
population rather than increases in per capita
consumption of dairy products. However,
increases in population should result in a
gradual increase in demand for dairy products in
the future.

^Research Dairy Scientist, USDA-ARS, U.S.
Dairy Forage Research Center, Madison, WI
53706

It appears that fluid milk demand will continue
to decline unless adults can be convinced that
milk is a healthy component in their diet. Milk
is consumed primarily by children, while adults
traditionally consume more carbonated beverages
and beer. It is difficult to envision that
adults will be convinced to drink milk as a
beverage in place of soft drinks. Few adults
think of milk as a thirst quencher after a game
of racquetball or long afternoon in the hay-
field. Perhaps milk should be promoted to adult
audiences on the basis of its health promoting
properties. Milk supplies calcium, a mineral
needed for bone strength especially in older
women. Calcium also has been associated with
reduced heart disease. Lactose promotes lower
bowel acidity and may be important in intestine
health and function. If each adult in America
drank a single glass of milk each day (whether
whole, 2% or skim) the demand for milk would
increase dramatically and the health of the
average adult would be improved.

Before addressing the main theme of this
presentation, it is important to address one
last topic the dairy industry must face
regarding production and demand. Americans do
not demand fat. Why are we still encouraging
fat production by an outdated method for pricing
milk? Pricing milk based on volume and total
solids would appear to be more rational.

Pricing on fat content forces dairymen to strive
against their industry's best interest. Is the
dairy industry being served by continuously
selecting and breeding dairy cows that produce
more fat?

Forages - Key to Future Dairying: Forages can
and will play a critical role in the survival of
individual dairy farms. The role of the
majority of dairy cows in the United States
(those located in the Northeast, Midwest and
North Central regions) is to convert forage
crops grown on the farm into a salable commodity
- milk. Even in areas of the country where most
feed ingredients are purchased, such as the
West, Southwest and Southeast, a majority of the
ration is forages or fibrous by-product feeds
that have little value unless converted to
milk. Too many dairymen and their advisors have
not realized that the function of a dairy cow is
to convert the product of the farmers land,
forages, into cash income. Too much emphasis
has been placed on feeding grain to maximize
milk production without realizing that the goal
is to maximize returns from the land. Once it
is recognized that the cow is the manufacturing
plant which converts the forage raw material
into a salable product, it is easy to understand
that management of both the plant (cow) and the
raw material (forage) are equally important.

Forages have both positive and negative
effects on dairy cow performance which influence
the amount of forage that can be fed. Minimum
forage is needed to meet the roughage value
requirement of cows. Roughage value is
associated with the chewing activity needed to

13

reduce feed particles to a size that can pass
through the digestive tract. Chewing activity
is important to the dairy cow because buffers in
the saliva that is produced during chewing
regulate acidity in the rumen. Salivary buffers
help maintain a rumen environment that optimizes
rumen fermentation and health. The negative
aspects of forages as feed ingredients are
related to their lower energy content than
concentrates and their bulky nature which tends
to limit feed intake. Survival of individual
dairy farms in the future will depend on the
optimum production and feeding of forages. If
too little forage is fed, off-farm feed inputs
become excessive and cow health suffers. If too
much forage is fed, feed intake and energy
content are reduced and cow productivity
declines. Dairymen of the future must insure
that high quality forages are grown, harvested
and fed properly in order to maximize the return
from their cows and land.

1 . Growing Forages . Much of the land located on
dairy farms in the United States is not suitable
for cash crop production. Forage production on
this land is logical both from the standpoint of
conserving soil resources and obtaining maximum
productivity from the land. However, it is
important to match the forage type grown with
soil characteristics. There is no single best
forage for dairy cows in all situations. Many
forages can be used to obtain profitable
production if managed and fed properly. It may
not be profitable to attempt to modify some
soils by excessive lime, fertilization, and
drainage systems in order to grow a specific
crop such as alfalfa. Alfalfa is an excellent
forage for dairy cows, but if it requires
excessive inputs to grow alfalfa on a specific
farm it may not be the most profitable forage to
produce and feed. In the future it will be
critical to select forages that fits the soil
and climate of each farm then feed them
optimal ly .

As a part of a program to minimize outside
inputs, more attention will be needed in
optimizing the use of recycled wastes. Energy
prices will eventually begin their upward
spiral. As they do, fertilizer costs will
become a significant factor in the cost of
forage production. Soil testing, combined with
a plan for retaining and distributing wastes to
maximize the recycling of forage nutrients, will
become important components in forage pro-
duction. Livestock manure should be considered
a resource to use in maximizing farm returns
rather than a waste to be removed. Like any
fertilizer, it should be applied based on soil
condition, crop requirements and timing.

2. Minimize Harvest and Storage Losses. Too many
forage nutrients are lost between the time
forages are grown and fed. Perhaps because it
is not viewed as an out-of-pocket expense, many
dairymen are willing to accept 15 to 35% loss of
nutrients that are grown. Convenience and lack
of proper planning and harvesting management are

often the culprits that steal too much forage
quality. In the future, forage types and
varieties will be selected to spread the
harvesting time over an interval that will
insure that the proper maturity is harvested for
all forages. At present, too many farms grow
one type and variety of forage which is
harvested over a three to four week interval;
thereby insuring that much of it is harvested at
maturities beyond optimum quality. Management
systems which use fertilizer applications,
north/south slope exposure, grazing or clipping
systems and alternative harvesting systems to
spread the optimum maturity time frame at each
cutting are needed. Systems are also needed for
harvesting and storing each maturity and quality
so it can be used most effectively.

Most of the nutrient loss in forage production
is related to harvesting and storage losses.

Many forage producers willingly accept har-
vesting losses of 25% while grain producers are
concerned about 2 or 3% losses during harvest!
Most producers are worried about weather damage
as the main loss; however, in terms of total
nutrients lost between standing crop and feed
bunk it may be one of the smallest losses. Too
many leaves are left on the ground or blown out
of the wagon by raking, baling or chopping
forage that are too dry. Equipment is needed
that gently moves forages as it is harvested.
More farmers in the future will be using
desiccants and preservatives to speed drying and
permit forages to be harvested at higher
moistures so that field losses are minimized.

The antithesis of producing quality forages is
the large round bale. At best it causes a 15%
loss of nutrients and often losses are near
40%. Isn't this price too high for conven-
ience? Would most dairymen accept 40% losses of
their corn crop as willingly? Although it is
clear that labor intensive haying operations
must be improved, loss of more than 10% of the
nutrients grown will not be acceptable in the
future. Similarly, the losses associated with
heat damaged protein in low moisture silages
cannot be tolerated. Silage production systems
must insure that the nutrients removed from the
field are fed to the cow. Losses in the silo
due to deterioration as well as heating are a
double loss. Not only are nutrients lost, but
also the labor, energy and wear on equipment
used to harvest and transport the nutrients to
the silo are lost. New technology will be
developed that allow silage and hay harvesting
in a 24 to 36 hour period thereby minimizing
weather and field losses of nutrients.

3. Allocation of forages. No matter how well
planned, the weather, mechanical problems and
forage differences will insure that all forage
harvested will not be a constant, high quality.

In order to maximize forage use, highest quality
forages must be fed to the dairy cows with
greatest nutrient requirements. Dairymen of the
future will realize that quality differences
among forages can be almost as great as the

14

difference between forages and concentrates.

Few dairymen feed the same amount and type of
grain to ail cows in a herd, yet forages are
often fed indiscriminately. Systems for
inventorying and allocating forages are needed.
This problem is greater for silage based systems
because the number of units and order of feeding
are locked in. However, as facilities are
updated or expanded, dairymen of the future will
use more storage units of smaller size to allow
optimal storage and allocation of the various
qualities of forage that are harvested.

4. Forage Analysis. There are many excuses for
not analyzing forages (too costly, too slow) but
none of them are valid. It is difficult to
maximize the use of forages and minimize the
fluctuations in milk production that occur with
changes in forages without nutrient content
information on the specific forages to be fed.
When used to formulate rations, forage analysis
doesn't cost, it pays. It is all too common for
cows to drop 2 to 4 lbs. of milk per day when
forages are changed and ration adjustments are
not made. The cost of feed analysis can easily
be paid with one or two days lost milk.
Conversely, properly balanced rations can easily
result in 2 to 4 lbs. additional milk per cow or
$.02 to .08 less daily feed cost per cow. These
returns can easily yield $1 to 3 for each dollar
invested in forage analysis. New technology
such as near-infrared reflectance spectro-
photometry and new chemical methods such as
neutral detergent fiber (NDF) will provide the
means for more rapid, less expensive and more
useful forage analysis information. Since the
NDF system separates feeds into digestible
neutral detergent solubles and less digestible
NDF, it provides an accurate way of comparing
all feeds. For example, brewers grains, early
maturity alfalfa hay and corn silage have
approximately the same NDF content, yet
conventional wisdom would call one a concen-
trate, one a forage and one a 50:50 forage:
concentrate mixture. The NDF system indicates
they have relatively equivalent feeding value
for dairy cows if particle size differences can
be ignored.

Since fiber is related to all of the major
characteristics important in forage quality
(roughage value, energy content and intake
limitation), fiber content is a critical
component of forage analysis.

It has been recognized for many years that crude
fiber (CF) does not measure all the fiber
constituents in forages. Lignin, an
indigestible fiber component, is partially
dissolved by the CF method and is not measured
as fiber. Hemicel lulose, an incompletely
digested structural carbohydrate is also
dissolved in the CF method. Acid detergent
fiber (ADF) has been proposed as an improved
fiber measurement system because it retains all
the lignin in the ADF fraction. However,
hemicel lulose is dissolved by acid detergent.
This causes discrepancies in comparing fiber
values of feeds which differ in hemicel lulose

content, such as grasses and legumes. Neutral
detergent fiber measures all three fibrous
constituents: cellulose, lignin and
hemicel lulose. The non- NDF, or neutral
detergent soluble (NDS), part of the feed
contains the proteins, sugars, starches and fats
which are almost completely digestible.

5. Formulating Rations to Maximize Forage

Feeding . At present, too much grain and
concentrates are fed in relation to the milk
production obtained. It is not uncommon to
observe farmers feeding 5-6000 lbs. of
concentrates in herds with 14,000 lb. herd
averages. Too many recommendations for feeding
dairy cows have not kept pace with changes in
forage quality. As little as 15 years ago,
excellent alfalfa hay was described as
containing 15-17% crude protein (CP). Today,
many farmers are harvesting alfalfa that
contains in excess of 20% CP. Fifteen years ago
it was necessary to feed 20 lbs of concentrates
to cows producing 60 lbs. of milk; however, with
today's high quality hays, 12-15 lbs. would be
adequate. For years, dairymen have been
extolled to feed more grain and improve forage
quality in order to achieve more profitable
dairy production. They have done both, but
doing so has not maximized the use of high
quality forages. Dairymen and their advisors
need to recognize that high quality forages can
substitute for concentrates and that overfeeding
grain results in inefficient use of high quality
forages .

Old guidelines recommended that high producing
cows be fed diets containing 50 to 60%
concentrates. This is valid for forages
containing 12-15% CP and 50-60% NDF, but not for
those containing 18-22% CP and 40-50% NDF. A
classic example of overfeeding grain involves
the use of corn silage. Typically, corn silage
is fed in rations with 50:50 forage : concentrate
ratios. Since corn silage contains 50% grain,
in reality the typical forage : concentrate ratio
is near 25:75. This is higher than necessary
for dairy cows, even when the low quality of the
corn stalks is considered. Most corn silage
based rations could be used more efficiently if
concentrate ratios were reduced and the protein
content of the concentrate increased.

New systems of formulating rations are needed
that can more accurately establish the correct
ratio of forage:concentrate to be used when a
specific forage is fed to a specific group of
cows with a given level of milk production.
Intake becomes the limiting factor which
establishes the maximum amount of forage which
can be fed and still meet nutrient require-
ments. The fibrous nature of forages limits the
cows' ability to consume them. Recent research
suggests that NDF can provide the basis for
future systems for formulating dairy rations.

The NDF content of forages is related to their
energy content and intake potential. By
combining NDF analysis of the forage with the
nutrient requirements of the cow for a target

15

level of milk production, the NDF system can
predict the forageiconcentrate ratio and NDF
content of the ration and the dry matter intake
of dairy cows that maximizes forage intake and
achieves target milk production. For example,
in order to produce 60 lbs. of 3.5% milk using a
ground shelled corn and soybean meal mixture
with a forage containing 65% NDF, the forage
concentrate ratio that maximizes forage intake
would be 46:54. However, if the forage
contained 45% NDF, the forage:concentrate ratio
which maximizes forage intake would be 71:29.

6. Using Fibrous By-Product Feed Ingredients.

Dairymen in the future will capitalize on the
dairy cow's unique ability to use fibrous
feeds. Many by-products of the beverage and
food industries provide valuable opportunities
for dairymen to purchase off-the-farm feed
inputs economically. Many of these feeds which
include; distillers' grains, stillage, brewers'
grains, gluten feeds, citrus pulp, beet pulp,
almond hulls, cottonseed and soybean mill feed;
have unique properties. Some provide a highly
digestible fiber source that can be used to
reduce the starch content of the ration. Others
provide slowly degradable proteins which can
escape rumen fermentation and be absorbed
directly by the cow. In the future, these feeds
will provide a lower cost alternative to grains
in dairy cow rations.

Non-Forage Factors Important to the Future of

Dairying: Although forage management will play a
crucial role in the dairy industry of the
future, many other factors will need superior
management in order for dairymen to survive.
Financial management will be critical to insure
that there is sufficient net income to service
debt and yield a return for labor and
investment. Greater control over capital
expenditures will be important as inflation rate
and interest rates begin to climb in the
future. Records of all types; financial, cow
health and reproduction, DHI, soil and crop,
etc; will be the keys to making decisions that
will be profitable and flexible. New computer
technology will become available using expert
systems that will help farmers analyze and
interpret the records he keeps. Records that
are not used are worthless!

More dairymen should be using artificial
insemination. There is no excuse for not
capturing the genetic gain that is provided by
sire summaries and sire selection programs. New
forms of genetic manipulation such as, embryo
freezing and transfer, and cloning, will become
available for augmenting the genetic gain in
milk production we can achieve. However, much
of the genetic potential of dairy cows is not
tapped at present, and first priority should be
given to proper cow care and feeding management
that will allow us to benefit from the genetic
material on hand.

New technology such as growth hormone and feed
additives will become available. Much concern
has been expressed about the impact of these

products on the dairy industry. Growth hormone
is especially exciting because of the potential
increases in production it elicits. I suspect
that the reality on the farm will be different
from the research in the laboratory. Unfort-
unately, growth hormone does not allow the cow
to create milk out of nothing. Like other
products such as thyroprotein, growth hormone
will stimulate additional requirements for
nutrients as milk production is increased. This
will place even more stress on the importance of
high quality forages and accurately formulated
dairy rations.

Conclusions : Forages will be the key to survival
for dairymen in the future. Most dairy cows are
used on farms where their role is to convert the
forage produced on farm land into a saleable
product. In the future, new technology and the
cost-price squeeze will place additional stress
on the production and utilization of forages and
fibrous by-product feeds. Greater care will be
needed in the future to insure that forages are
grown, harvested, stored and fed with a minimum
of losses. Forage is a valuable product on most
farms which deserves optimal management and
uti 1 i zation.

16

GRASS

- THE NEXT CINDERELLA CROP
H. Allan Nation

Agronomists all over the United States are scan-
ning the horizon for the next Cinderella crop to
hit American agriculture. In the 1970 's the Cin-
derella crop in much of the U.S. was the soy-
bean, but today with fearsome competition aris-
ing in the Southern Hemisphere the soybean looks
more and more like the Wicked Stepmother to
farmers who grow it. Corn, wheat, cotton and
rice are all in gross oversupply in the United
States, and few expect a dramatic turn-around
in the demand for any of those U.S. crops in
the remainder of this decade.

I hope to be able to make a credible case that
America's Cinderella crop for the remainder of
this century is all around you. It is here and
has always been here and that crop is grass.

The Good Lord in his magnificent plan for the
universe has deemed grass to be the ultimate
climax crop in his universe. He absolutely will
not allow a bare piece of ground. Grass cools
the soil, tempers the fall of the raindrop, and
heals and rebuilds the soil, organic matter and
nitrogen. Grass is the only crop we can grow
that puts more into the soil than it takes out
of it.

The stirring and tilling of the soil and the
planting of monocultures is not found naturally
anywhere on earth. These activities eventually
destroy the organic matter God's grass crop
carefully built in the soil and will economi-
cally destroy the farmer eventually. Without
organic matter, the soil's lifeforce of microbes
dies, and when the life dies in the soil crop
residues will no longer recycle. Herbicides will
no longer work and can actually do more damage
than good. The soil has no water holding ability
and the soil will eventually literally blow in
the wind.

In the Mississippi Delta, farmers are having to
almost continuously run center pivot irrigators
to grow cotton in a 60 inch rainfall area. The
soil has so little organic matter that it can
only hold one-half an inch of water in an area
where the summer daily evaporative rate is one-
third of an inch. The only thing that can break
the death spiral for these farmers is to put
this land back to grass for four or five years
and heal the soil. Unfortunately, many of these
farmers were able to get a degree in agriculture
with virtually no understanding of soil science
or ecology. They, in their ignorance, still be-
lieve that cotton is king and grass is something
you try to kill.

These farmers, who are going broke by the bushel
basket, will tell you their land is too good
for grass and yet any soil scientist can tell
them that their land has been rendered virtually
worthless by their continuous cropping. Research
in Georgia shows a virtual doubling of yields
for any subsequent crop grown behind five years

of a sodgrass, and yet 75 to 80% of the chemicals
used in American agriculture are sold to kill
grass .

There is a reason why these farmers are going
broke, and it has less to do with prices and ex-
port markets than it does with ignorance of the
basics of soil science. Why was this allowed to
happen? The base reason was money. The whole
research and communications establishment of
American agriculture sold out to the boys who had
money, which were the chemical and fertilizer com
panies. Farm magazine publishers realized the
big bucks were those double-page spread herbicide
ads. Researchers realized the big bucks were in
ridiculous product A versus product B product
testing rather than trying to figure out how not
to use either product A or product B.

Any of you who get any free farm magazine or any
farm magazine with a ridiculously low per year
price need to realize that magazine is working
primarily for his advertisers. You also need to
realize that a lot of the research information
you read was bought and paid for by some chemical
company. I am not saying that any of this infor-
mation is false, but that all of it is skewed
toward the use of greater petrochemical inputs
rather than rotation, diversification and working
in harmony with nature .

I don't have to tell any of you what has been the
result of this shift to petrochemicals and high
capitalization. You can see the results in your
community as well as on the evening news every
night. Anyone who bought this line from the Fede-
ral Land Bank to International Harvester is sick
and near death.

The reason people are starving in Ethiopia is be-
cause a society built on grass and nomadic sus-
tainable grazing bought the whole boat of modern
agriculture and shifted to unsustainable rowcrop
agriculture. There has never been a civilization
in history that has been economically sustainable
based around rowcrop agriculture, whereas civili-
zations based upon grazing have existed for thou-
sands of years.

It is not hard to sell the idea that rowcrop
farming is not profitable today. What is diffi-
cult is to sell the idea that grass is probably
the most profitable crop a farmer can grow in 99
cases out of a hundred. Our problem has been that
we have not looked at grass as a crop and our-
selves as grass farmers. Animals are merely the
combines for the crop. No rowcrop farmer would
ever use a corn header to harvest wheat and yet
we mismatch animals and their environment with
little thought. Too many of us describe ourselves
as cowmen, or sheep men, or yearling operators
with too little thought about whether our environ
ment matches our animal decision.

In much of the United States, the grass growing
season is only 60 to 100 days long and snow
covers the ground for six months or more. Such
environments do not lend themselves to year-
round cow-calf production nearly so well as

17

seasonal Stocker operations. In much of the
United States, combinations of species and class-
es of animals offer a much better harvest than
any one species or class. All of our grasses have
seasonal protein requirements high enough to
allow our grazing animals to breed and our breed-
seasons must mesh with these periods.

We have placed entirely too much emphasis on
weaning weights and not nearly enough emphasis
on genetically matching animals and their envir-
onments. For example, much of the Southwest is
covered with brush and yet there are cattle in
Africa who can make up 90% of their diet from
brush. It would be much more cost-effective to
genetically adapt the cattle to the brush than
to chemically adapt the environment to our pre-
sent breeds of cattle.

There will never be one "ideal" steer in the
United States. Genetics will have to be altered
to allow the animals to maximize the harvest of
the existing environments. The correct emphasis
for any cowman is not on the steer calf but on
the replacement heifers he is carefully adapting
to his specific environment. Genetic adaptation
comes not so much from the bull we buy, but the
cow we cull. The more ruthless we cull, the fast-
er we adapt our herd. A 75% calf crop indicates
that we are three-quarters of the way there in
getting rid of cows who can't hack it under our
environment .

Our customers, the American comsumers, are tell-
ing us to route fewer animals to the feedlot and
more to the hamburger stand. We need to allow
every heifer we produce to have a chance to make
it as a productive breeding animal that is better
adapted to our environment than her mother. If
she, in fact, proves she is so adapted. Momma
goes to McDonald's and daughter takes her place.
Those who say we have too many cattle in the
United States totally overlook the fact that we
import one billion pounds of hamburger grade
beef a year. That's the slaughter equivalent of
the entire cowherd of Missouri, our second lar-
gest cow-calf state.

Our post-weaning steer programs need to be re-
geared for producing animals in the 850 to 1000
pound weight category prior to being placed in
the feedlot for a quick finish. Our critics
point out that cattle are wasteful users of the
grain resources of the world. Economists point
out that cattle will never anywhere equal the
feed efficiency of chickens, and both the critics
and the economists are right. However, if we
place cattle on feed at this weight category,
the total feed efficiency of grain to liveweight
slaughter equals or exceeds that of poultry.

I'm not going to overly worry about poultry com-
petition until they breed a bird that can gain
two pounds a day on grass, and as far as a waste
of our grain resources, I am far more worried
about our waste of grass resources.

The central plains area was originally a summer
fattening range for yearlings driven up from
Texas and it worked extremely well as such. When

we started shifting the post-weaning growing pro-
gram from grass to grain, we created a huge under-
utilized resource. Man hates to see a resource
go to waste, so we expanded the only part of the
cattle business left to grass - the cow. This set
us off on the roller coaster we have been on for
the last 35 years, whereby the availability of
grain rather than grass dictated the size of the
cow herd. Every mouthful of grass a steer eats
relieves the pressure to have that mouthful of
grass eaten by a cow.

If we start routing cull cows to slaughter rather
than heifers to the feedlot, and if we start
growing all our steer production to 850 to 1000
pounds before placing them on feed, you can start
to see that we could have a much better utiliza-
tion of our grass resources without that much
increase in total tonnage of beef. It would also
largely free us from the grain market vagaries.

We do not have cattle to eat surplus grain. We
have cattle to harvest grass.

Let's look at the pieces of our puzzle so far.

We've got a crop that God will grow for free.

We've got a harvesting machine that runs on sun-
light and water, but we've had one key element
missing. That element was the ability to efficient-
ly control and steer our harvesting combine. And,
it was this one missing element that allowed row-
crop farming to be more profitable than grazing.

Consider for example the economics of growing a
crop, but having a combine aimlessly churning
through the field during the entire growing
season. It would be bad enough if this combine
were only loosed to do its damage when the crop
was ready to harvest, but I am talking about a
combine that wanders aimlessly over the crop
from the day the first seed is planted. Picture
that please. Can you imagine how much of the
crop would be crushed by the wheels of the com-
bine compared to how much wound up in the hopper?

While this sounds totally ridiculous in the con-
text of a soybean or corn crop, it is precisely
how we have been attempting to harvest our grass
crop. Our cows only harvest approximately one-
third of the grass we grow with continuous graz-
ing .

Our biggest problem in grassland farming has been
that we have been attempting to grow more grass
rather than attempting to more efficiently har-
vest what we have already grown. It is on this
one key missing piece of the puzzle that all of
our grassland economics have foundered, and it
is on this one key piece of the puzzle we are
starting to separate the men from the boys, and
the winners from the losers, in the grass busi-
ness.

In my opinion, the greatest technological break-
through in the history of the cattle business
has been these new New Zealand electric fences.

As a boy, I grew up on a commercial cattle ranch,
and I hated every minute of it. Looking back, it
was not the cows I hated. It was those damned
barbed wire fences that were always needing re-

pair. I recently visited a man in Alabama with
9000 head of cattle, and not one fence on his
place was more than a one wire New Zealand style
electric fence.

Fencing costs, which were the major capital cost
of a grassland farming operation just a few
years ago, are a minor expense now. Now for the
first time, we can start effectively controlling
that combine on our crop. Just like the rowcrop
farmer, we can let our crop get to its optimum
harvest stage and then whack it off with our
combine. Then just like the rowcrop farmer, we
can keep our combine off the crop until it is
at its peak and whack it off again.

Like the cotton farmer, we can also pick and
scrap. We can let our yearlings pick the prime
crop and the cows follow them and scrap the rest.
With control over our cattle, we can start ef-
fectively harvesting alfalfa, johnsongrass ,
orchardgrass , and other extremely high quality
forages that were previously only harvestable as
hay.

Rather than going to all the trouble of harvest-
ing corn as silage, we can grow a corn crop,
allow it to stand and dry down until we need it
in the winter, and then take one of these reel-
type electric fences and ration off only as much
of the corn crop as our yearlings can eat that
day. In effect, we can combine a rowcrop just
like a grass 'crop.

Want to fatten steers on grain sorghum? Stagger
plant your crop and strip graze it while the
grain heads are still in the soft, green, doughy
stage. After you've gone across the crop like
this approximately twice in much of the U.S.,
you'll still have an excellent standing hay
crop to winter your dry cows on. Virtually any
crop we can harvest with an oil-burning, iron
combine, we can harvest with a solar-powered
animal combine.

I hope I have shown you that all of the pieces
of the puzzle are finally in place. All we need
now are grass farmers willing to put these
pieces together in their most optimum form for
their particular area. If you'll forget the
past, ignore prejudices and old wives' tales
about cattle and grass, and if you'll start
to think of grass as a crop and animals as a
combine, I think you too will start to see that
grass is indeed America's next and most endur-
ing Cinderella crop.

1/ H. Allan Nation is editor of The Stoc)onan
Magazine in Jackson, Miss.

THE BEEF INDUSTRY AND ITS FUTURE
1

David G. Topel
ABSTRACT

The future of the beef industry can be very
bright and consumption of beef can increase if
the industry initiates programs which will
greatly reduce production costs and market very
lean, low calorie beef. Use of excellent
forages in the production systems can help
reduce production costs and also result in very
lean beef for the consumer.

The tremendous amount of new technology which
has been developed in recent years both for
production and processing of beef provides some
excellent opportunities for innovative
industrialists who are willing to develop low
fat, but quality beef products. The
application of new technology from production
through processing may be considered a high
risk business by traditional people in our
industry. People with a good business and
management background, however, could easily
take the existing technology and produce very
lean and quality beef at much lower production
costs than exist in our current system. An
excellent forage ^stem is essential for low
cost cattle production. The timetable in which
the technology will be incorporated into our
system is unknown, but I would be surprised if
much of this technology is not utilized on a
commercial basis before the year 2000. I know
that we have well established management
personnel in the beef industry who are giving
serious consideration to many of the concepts
which were discussed in this paper.

We will see more changes in the beef industry
in the next fifteen years than we have observed
in the last forty. The consumer is demanding a
different type of beef product than we’ve had
previously. These demands will result in major
changes in the livestock and meat industry.

INTRODUCTION

The livestock and meat industry has undergone
some dramatic changes in the past thirty
years. The industry has greatly reduced the
total fat in the meat producing animals
marketed in the United States. These changes
are a result of the consumer demands for less
fat and more lean meat in their diet. The
poultry industry has made even greater
changes. The poultry industry has used maximum
genetic improvement combined with efficient
production practices to produce high quality,
but low fat poultry meat products for the
American consumer. These practices have
resulted in lower production costs for poultry

^Department of Animal and Dairy Sciences,

Auburn University, Auburn, AL 36849.

meat compared to the red meat industry. The
tremendous improvements in efficiency of
production by the poultry industry have
resulted in much lower retail cost for poultry
meat products and a major increase in consumer
demand. Table 1 shows the per capita
consumption of poultry meat products versus red
meat products from I960 through 1984. The per
capita consumption of poultry meat and meat
products has continually increased each year
from i960 to the present. A major shift in
consumer preference for poultry meat compared
to red meat was clearly reflected by the
American consumer in 1982. In 1982 poultry
meat accounted for 32? of the total meat
consumption and a major increase from 1973.
Beef, however, decreased from 1973 to 1982
(Table 1). The consumer trends which have
occurred in the last ten years for lower
calorie foods will continue to occur over the
next decade. Therefore, the future of the beef
industry will depend on its ability to develop
more efficient production systems and market
animals with considerably less fat.

Table 1. United States Cogsumption of Pork,
Beef and Poultry

Year

1960-63

1970-73

1982

1983

1984

Pork

59.5

62.7

59.0

62.2

60.8

Poul try

36.8

49.6

64.1

65.4

66.0

Beef and Veal

71.2

85.3

78.8

80.4

80.6

Expressed in pounds.

We must not only be concerned about improving
our efficiency of production, but we also must
reduce the energy cost associated with our
processing methods in the meat industry. Red
meat processing, the most energy intensive of
all the food industries, has become vulnerable
to fluctuations in the energy supply. Further
energy efficiencies, however, can be achieved
through processing innovations and economic
alternatives for energy utilization by the
meat industry (Hendrickson, 1981). It is
evident that our greatest challenge will be to
improve the efficiency of production and
processing techniques. Our economy will
dictate this change to the industry and the
competitive pressure from the poultry industry
and non-meat protein sources will provide
great competition in the next ten years for
the beef industry. For the beef industr*y to
be competitive in the year 2000, the ideal
carcass will have considerably less fat than
exists in the carcasses produced in 1985.

THE BEEF CARCASS CHALLENGE

The beef cattle industry has made great
progress in reducing the fat in the Prime,
Choice, and Good grade carcasses merchandised

20

for the retail industry (Table 2). The beef
industry in the last three years, has greatly
reduced the dollar value for yield grades four
and five which represent the extremely fat
beef carcasses. The cattle feeder
merchandising overly fat cattle in 1985, could
receive as much as $120 less per animal as
compared to trimmer cattle which represent the
yield grade one through three. The severe
discount for over finished cattle certainly
will have an immediate impact on the cattle
feeder to merchandise trimmer cattle.

Table 2. Carcass Yield Grading as a Percentage
of Pounds of Graded Carcasses

Year

YG1

YG2

YG3

YG4

YG5

66

1.5

41 .8

54.6

2.0

0.2

67

0.9

35.4

61.9

1.7

0.1

68

0.8

33.8

64.0

1.3

0.1

69

1 .0

37.2

60.8

0.9

0.1

70

1 .0

32.8

65.4

0.7

0.1

71

0.8

31 .4

67.0

0.8

0.1

72

0.5

26.5

70.6

2.0

0.1

73

0.8

27.5

67.9

3.4

0.4

7i1

0.8

25.1

67.3

5.9

0.9

75

1.7

31 .2

63.6

3.2

0.3

•76

1.9

28.4

57.5

10.3

1.7

77

2.4

30.9

57.2

8.3

1.1

78

2.2

30.4

58.3

8.2

0.9

79

1 .8

28.9

58.8

9.3

1.2

80

1.7

28.9

58.3

9.7

1 .4

81

1.9

30.4

57.1

9.4

1 .2

82

2.3

35.9

54.6

6.6

0.7

83

2.5

36.3

54.3

6.3

0.7

••84

3.3

42.0

49.6

4.7

0.3

•Changes in the Beef Grades Standards which
became effective in 1976 required that all
carcasses quality graded also be yield graded

•*7 month data.

^Data were obtained from USDA, May, 1985.

It is possible that the beef cattle industry
will have more than one type of ideal carcass by
the year 2000. I would anticipate a certain
demand for high quality beef as it exist today.
This type of beef will continue to be very
expensive, but sufficient Americans will have
the finances and desires to purchase this type
of beef for their daily menu. I can also see
another group which will prefer extremely lean
beef which is practically devoid in marbling.
This beef will be produced in production systems
which emphasize forage rather than grain as a
major component of the ration for beef cattle.

I believe these production systems will continue
to grow in number and we will have a gradual
shift of the beef industry from the traditional
feedlots to regions which can produce large
quantities of forage without irrigation
systems. This program would require the

develofxnent of new packing plants and the
application of new technology in the fabrication
of high quality and lean beef products by modern
processing techniques. These methods can
greatly reduce the cost of lean beef products at
the retail level and provide a good margin of
profit for all phases of the beef industry. By
the year 2000, I would expect an increase in
lean beef production and a decrease in the
traditional grain fed beef industry which exists
today. In the next 20 years, there may not be
one ideal beef carcass, but several ideal
carcasses which will meet the needs of a
specific component of the consuming public in
the United States. After the year 2000, I would
project that the majority of the carcasses
produced in the United States will be
practically devoid in marbling and have
approximately .1 inches of subcutaneous fat.

GENETIC BASE

The genetic base for the cattle industry is
extremely variable. The incorporation of exotic
breeds into the traditional English breeds used
for many years in the United States has resulted
in tremendous opportunities for the cattle
producer to greatly improve the growth rate and
reduce the fat in the cattle population of the
United States. A large number of countries have
selected for reduced fat and increased muscling
many years before the U. S. cattle industry
decided it should reduce the fat content in the
beef merchandised at the retail level. Because
the genetic base already exist for the cattle
industry, we'll only need to incorporate the
desirable production traits of various breeds
with the desirable carcasses traits of other
breeds and implement an excellent crossbreeding
program which will incorporate the economic
production traits with the production of lean,
quality beef for the American consumer.

The concepts of strong on- the- farm testing
programs are essential if the beef industry
plans to be competitive with the poultry
industry in the future. Even though we have a
strong genetic base to reduce the fat and
produce quality beef products for the American
consumer, it is extremely critical that we
continue to identify the most efficient and
productive seedstock animals that will reduce
the production cost and provide greater profits
for all segments of the beef industry.

CONSUMER PREFERENCES

The beef industry developed an extremely strong
market for high quality, but fat beef from 1950
through 1982. In 1982, beef consumption
decreased and poultry consumption greatly
increased (Table 1). With the major emphasis on
low fat diets and other discriminatory comments
about beef regarding human health and nutrition,
a large number of consumers are purchasing less
beef. This is particularly true of a select

21

group of high income consumers who have altered
their eating habits and prefer light foods with
lew fat content (Yankelovich, et al., 1985).

The surveys conducted by the National Livestock
and Meat Board clearly shew that the consumer
prefers beef with considerably less marbling and
less total fat than exists in the current
U. S. D. A. Choice grade.

MARBLING VS PRODUCTION EFFICIENCY

The major factor responsible for high production
cost for beef produced in the United States is
directly related to the marbling requirsnent
associated with the Choice grade. This has been
an extremely controversial topic by all segments
of the beef industry. It is difficult to
understand this controversy because an objective
review of the research reported on this topic
clearly shews that marbling has limited
influences on all palatability traits (Parrish,
1981). Meat scientists all know the limited
influence of marbling on beef palatability.
Scientists as well as industry leaders who want
to promote the marbling concept find small
differences that may exist in certain studies
and use these data to support their views. If
the industry is going to be competitive with
other muscle foods in the future, these concepts
will have to be removed from the leadership of
the industry and we will have to produce beef
with less subcutaneous, intermuscular, and
intramuscular fat. It is very possible to
produce beef carcasses with 73% muscle, .1
inches of fat at the 12th and 13th rib and still
maintain excellent eating quality if the cattle
are merchandised at a young age of 18 months or
less. A comparison of the ideal carcass for
1968 versus the year 2000 (tables 3 and
indicates that the major differences is
associated with the reduction of the three fat
components of the beef carcasses.

Table 3. The Ideal Beef Carcass (1968)

Trait

Statistic

Carcass weight, pounds

600-650

Maturity

15 months

% Round, loin, rib.

chuck

53 (Yield Grade 1 )

% Edible portion

67

Loin eye area

14 square inches

Conformation score

Choicei- to Prime-

Fat thickness, 12th

rib

0.3 inches

% Kidney fat

2.5

Marbling degree

Small to modest

From: D. M. Allen, 1968 Proc. Reciprocal Meat
Conference,

Table h. Desirable Beef Carcass (Year 2000)

Trait

Statistic

Carcass weight

700

Maturity

20 months

% Muscle

73

Loin eye area

15 square inches

Fat thickness

0,1 inches

% Kidney fat

1 .0

Marbling score

Practically devoid

It is well established that extreme muscling
deposition in beef carcasses along with a
minimum amount of fat (.1 inches or less) can
result in an abnormal condition often referred
to as "double muscling". Cattle which possess
double muscling traits have extreme reproduction
problems and possess stress susceptibility
traits that are undesirable in beef production
systems. Fortunately, the beef cattle industry
has a genetic base which can produce muscular
and trim carcasses and prevent the development
of double muscling characteristics. To
guarantee that the introduction of the genes
associated with double muscling are not
increased, it will be necessary for the
seedstock producers to develop a sound selection
program which includes performance testing of
economic traits associated with efficient
production of quality, but low fat beef.

The existing production systems for beef cattle
in the United States are extremely costly and
require an intensive energy utilization for both
production and processing. One method to reduce
production cost for the beef industry is to
reduce the fat content of the carcass and
incorporate production systems which require
less grain and more forage. Fortunately,
production systems exist in the United States
where maximum forage utilization can be used to
produce beef cattle to a live weight of 900 to
1000 lb. These cattle can be placed in a
feedlot and fed for sixty days on a high energy
diet and be marketed in 18 months or less.
Production systems of this type can greatly
reduce the production cost and still provide a
high quality rapidly acceptable beef product for
the American consumer (Schmidt et al. , 1985).
Even though ^sterns of this type exist today,
they are often rejected by leaders of the
industry because of the major economical
investments in the existing, but traditional
packing plants and feedlots which currently
account for over 80% of the Good and Choice beef
produced for the retail stores in this country.
Unless the beef industry makes major changes in
its production practices which will improve the
efficiency, we will have a difficult time in
competing with other muscle foods in the year
2000. Our greatest challenge in the beef
industry may not be producing an ideal carcass
with minimum fat, but produce a carcass that
can be competitive with other muscle foods. We

22

have the technology for these systems, but we do
not have an acceptable attitude of the existing
beef cattle industry to incorporate the new
technology which exist in reducing production
costs for steaks and roasts merchandised at the
retail stores. Because of the tradition and
extremely large investment to produce the
traditional steaks and roasts for the beef
industry, it will be very difficult to make
major changes in the beef industry before 1990.

I believe from 1990 to the year 2000, the
industry will be forced to make major changes in
its production practices and processing
techniques. Because existing technology already
is available to make sweeping changes in the
beef industry, it appears that strengent
economical situations will have to exist before
this technology is incorporated into our
production and processing systems. I believe
that by the year 2000, we will find a beef
cattle industry more dependent on forage
utilization and major changes will occur in the
processing of beef to provide extremely lean but
tasty beef products.

Literature Cited

Allen, D. M. 1968. Description of ideal

carcasses. Proc. Recip. Meat Conf . 21:284.

Hendrickson, R. L. 1981. Energy aspects of
prerigor meat. Proc. Recip. Meat. Conf.
34:81.

May, M. 1985. Personal Communication, USDA
Meat Grading Service. Washington, D.C.

Parrish, F. C. 1981. Relationship between

beef carcass quality indicators and pala-
tability. Proc. National Beef Grading
Conference. Iowa State University, Ames,
lA p. 46.

Schmidt, S. P., T. B. Patterson, L. A. Smith,

H. W. Grimes, J. L. Holliman. 1985.
Postweaning performance of two manage-
ment systems of calves out of Angus-
Hereford and Simmental-Heref ord cows
bred to Angus and Polled Hereford bulls.

J. Anim. Sci. 61 (Suppl. 1):426.

Yankelovich, D. , F. Skelly and A. White. 1985.
Consumer climate for read meat: Executive
Report. National Livestock and Meat
Board, Chicago, Illinois.

23

FORAGE LEGUME BREEDING IN FLORIDA

David D. Bal|ensperger, G. M. Prine, K. H.
Quesenberry

The University of Florida, Institute of Food and
Agricultural Science (IFAS) has been involved with
forage legume improvement for most of it's more
than 100 year history. Currently there are more than
3 full time equivalents (FTE's) devoted to forage
legume breeding. This includes partial research
efforts of seven scientists working on more than a
dozen genera of temperate, subtropical and tropical
legumes.

Forage legume breeders are located at the IFAS,
Agricultural Research and Education Center at Fort
Pierce, Florida and at the main campus in
Gainesville, Florida. Testing is conducted at these
locations and at seven other research centers located
throughout Florida.

TEMPERATE LEGUMES

Alfalfa (Medicago sativa) persistence and
productivity in the humid southeast have been the
primary goals of Dr. Earl Horner's program for more
than 30 years. This program led to the development
of 'FL 66', 'FL 77' and an improved population which
is currently being evaluated for potential release.
These cultivars and improved populations have
consistently been the most persistent and productive
in Florida. The current population has high levels of
resistance to several root-knot nematode species and
to the spotted alfalfa aphid.

White clover (Trifolium repens) breeding work was
initiated by Dr. Horner more than 30 years ago also.
The program has passed through the hands of several
breeders in subsequent years, but the goal of
improved persistence and productivity has stayed the
same. This resulted in the release of 'Osceola' white
clover and subsequent improved populations that are
currently under regional evaluation for release. Short
term goals of this program have shifted to improved
nematode and virus resistance along with enhanced
seed production potential.

Crimson clover (T. incarnatum) breeding work was
initiated by Dr. G. M. Prine and continued under the
direction of Dr. D. D. Baltensperger. Evaluation of
numerous collections for immediate release and
development of a broad based population for future

Assistant Professor, Professor, and Associate
Professor of Agronomy, respectively, IFAS, University
of Florida, Gainesville, FL 3261 1.

selection is now underway. Some of these
collections are currently being evaluated in regional
trials. It is anticipated that the most promising,
Fl-XPC-B, will be released in the coming year
(Table 1). Current populations of early and late
maturity are being screened for improved root-knot
nematode resistance.

Table 1. Maturity of crimson clover, April 5, 1985.

Gainesville

Germplasm

Dairy

Campus Jay

FL XPC B

100

—% flowering —
100 95

Chief

20

10

5

Dixie

40

40

60

Tibbee

60

40

80

Subterranean clover (T^. subterraneum) research has
only recently advanced from the evaluation of plant
introductions and Australian cultivars to the
evaluation of naturally reseeding ecotypes for
root-knot nematode resistance. Controlled crosses
are now being made between resistant types and
agronomically desirable types. Material from this
program will not be ready for regional evaluation
for at least three years.

Arrowleaf clover (T^. vesiculosum) has been declining
in productivity rapidly over the past five years in
Florida. This decline has been associated with
viruses, root-rots, and nematode buildup. The
primary goal of the arrowleaf clover breeding
program has been to identify and incorporate
resistance to these pests, however, little positive
variation has been identified to date. A major
commitment and a little luck will be required to
maintain the present acreage of this once popular
legume.

Red clover (T^. pratense) breeding was initiated by
Dr. G. M. Prine and Dr. K.H. Quesenberry. Seed of
three populations selected for (1) vigor, (2) early
flowering, and (3) improved root-knot nematode
tolerance are currently being increased for further
regional testing. All populations have been shown to
have higher root-knot nematode tolerance than more
temperate germplasm. We expect that a new
cultivar of this promising crop will be released
within the next three years.

SUBTROPICAL AND TROPICAL LEGUMES

Aeschynomene (Aeschynomene americana) breeding
research has been directed by Dr. K.H. Quesenberry
for the past 7 years. Improved quality and less
woody growth types, compared with the common
type, have been selected. Grazing trials are

Z4

currently being conducted on progenies that also
carry nematode resistance. Additional grazing data
will be collected prior to the release of the most
promising of these. Studies on the inheritance of
root-knot nematode resistance and photoperiod
sensitivity are currently being conducted to provide
an improved knowledge base for future breeding
research.

Hairy indigo (Indigofera hirsuta) breeding research
has been directed at improved seedling vigor and
root-knot nematode resistance. A soft-seeded type
with substantially larger seed has been identified.
Crosses with the more agronomically desirable and
disease resistant types are now being made.

Alyceclover (Alysicarpus vaginalis) utilization has
been seriously hampered by susceptibility to
root-knot nematodes and solving this problem has
been the primary goal of the breeding program.
Sources of resistance to each of three root-knot
nematode species have been identified and crosses
are currently being attempted to consolidate
resistance to all three species in one line. Variation
for seedling vigor, photoperiod sensitivity, forage
quality and other traits has also been identified,
however, no successful crosses have yet been
achieved. Crossing technique development has
subsequently become the highest priority. Lines with
resistance to at least two of the nematodes are
currently being evaluated for direct release.

Desmodium research has centered around the
heterocarpon species and the closely related species,
ovalifolium. Root-knot nematode resistance has been
the primary breeding objective and sources of
resistance have now been identified, especially high
levels in J5. ovalifolium (Table 2). The first successful
crosses of j). heterocarpon x j). ovalifolium have been
achieved and this gives encouragement to the long
term goal of transferring the nematode resistance.

Dr. A. E. Kretschmer, ]r. initiated Desmodium
research more than 20 years ago and is still actively
collecting germplasm around the world. Dr.
Quesenberry is currently doing the breeding research.

Perennial peanuts (Arachis glabrata and other spp.)
have been introduced and evaluated in Florida by
Dr. A. E. Kretschmer, 3r. and G. M. Prine. This has
led to the recent release of the nematode resistant
cultivars 'Florigraze' and 'Arbrook'. Essentially no
seeds are produced by these two cultivars. However,
in the spring of 1986 several plants arising from
seed were identified in a field that had been dug
for rhizomes in the previous winter. These seedlings
are now being evaluated for genetic variation and
their potential to produce other seed.

Stylosanthes spp. breeding research has been
directed by Dr. 3.B. Brolmann for the past 15 years.
Emphasis on cold hardiness, disease resistance,
forage quality and most importantly, persistence,
have led to the development of several lines which
are currently being evaluated for cultivar release.

Dr. A. E. Kretschmer, 3r., C. G. Chambliss, and W.

H. Pitman are currently evaluating collections of
numerous other subtropical and tropical legumes for
persistence and forage quality. Included in this work
are the genera Vigna, Centrosema, Arachis,
Desmanthus, Teramnus, Zornia, and others. Dr. G.M.
Prine is doing similar work with subtropical and
temperate species including Lotus, Vicia, Lespedeza,
Cajanus, and others.

The continuation of these research efforts through
the year 2,000 should lead to the development of a
forage system with improved seasonal distribution of
high quality forage for livestock production. Major
advances can and must be made in the consistency
of production of each of these forage legumes if
they are going to play a part in fulfilling this
long-term goal of all forage legume breeders.

Table 2. Gall scores of Desmodium spp. in response
to infestation with Meloidogyne spp.

Meloidogyne Species

Desmodium

Species

arenaria

incognita

javanica

heterocarpon

Fl-20

3.6

4.5

5.0

Fl-143

3.9

4.4

5.0

FI- 149

3.6

4.9

5.0

ovalifolium

Fl-28

2.4

0.2

3.1

Fl-146

2.4

0.1

2.5

Fl-147

2.4

0.0

3.3

25

GERMPLASM IMPROVEMENT IN THE MISSISSIPPI CLOVER
BREEDING PROGRAM

W. E. Knight, M. M. Ellsbury, M. R. McLaughlin,

G. A. Pederson, R. G. Pratt, and G. L. Windham!/

The major emphasis of the Mississippi clover
breeding program is on host-plant resistance to
provide perennial and annual clover germplasm
and/or cultivars with improved reliability and
productivity through increased resistance to
insects and diseases and to environmental stress.
The major species in the program are arrowleaf
clover. Trifolium vesiculosum Savi., berseem
clover, T. alexandri num L., crimson clover,
incarnatum L.; subclover, T. subterraneum L. and
white clover, T. repens L. This report will
review recent releases from the program and the
status of other germplasm under development.

RELEASED GERMPLASM
Bigbee Berseem Clover

'Bigbee', a winter-hardy berseem clover, was
developed cooperatively by the USDA-ARS and the
Mississippi Agricultural and Forestry Experiment
Station (4,5). Bigbee is a selection for winter
hardiness from the Italian cultivar Sacromonte.
Selection was made during the growing seasons of
1970 to 1971 and 1971 to 1972. In January 1972,
stands of Sacromonte were subjected to -15°C and
-18°C within the same week. Seed was increased
from surviving plants and evaluated in the
Regional Annual Clover Variety Test from 1977 to
1983. Bigbee is the first cultivar of berseem
clover to survive north of the Gulf Coast and
Peninsular Florida. The level of winter hardiness
in Bigbee gives it the same approximate range of
adaptation as arrowleaf clover and crimson clover.
Bigbee is susceptible to crown rot (caused by
Sclerotinia trifoliorum Eriks.) root diseases,
nematodes and bean yellow mosaic virus disease
common to other forage legume species (1). To
date, stands have not been lost from disease
epiphytotics such as the virus-root rot complex
which has destroyed stands of arrowleaf clover.

Bigbee was named and released in March 1984 by
USDA-ARS and the Mississippi Agricultural and
Forestry Experiment Station. Generations of seed
increase are one generation each of breeder,
foundation and certified. Breeder seed shall be
maintained by the USDA-ARS at Mississippi State,
MS. foundation seed will be produced by

1/ USDA-AR'S

Crop Science Research Laboratory
Forage Research Unit

Mississippi State, Mississippi 39762-5367

Foundation Seed Stocks, Mississippi Agric. and
For. Exp. Stn., Mississippi State, MS 39762.

An exclusive release for market development and
distribution was negotiated with Funk Seeds
International. Adequate amounts of certified seed
should be available in 1986 to meet the demand for
this cultivar.

CHI -1 Crimson Clover

CHI-1 crimson clover germplasm was released by the
Texas Agricultural Experiment Station, the
Mississippi Agricultural and Forestry Experiment
Station and USDA-ARS in December 1985 (17). CHI-1
is a simply inherited, non-strain specific, inef-
fective nodulation characteristic in crimson
clover. A single plant of crimson clover with
ineffective nodulation was selected under nil-N
conditions from a 1000-plant population of 'Chief
(16). Ineffective nodulation is controlled by a
single recessive gene pair (rt^, rt^) with
possible modifiers. Plants with this trait should
be useful as non-N2 fixing controls in 15^j isotope
dilution experiments and to study individual steps
in N2 fixation. Seed may be requested from
G. R. Smith, Clover Breeding Program, Texas
Agricultural Research and Extension Center,
Overton, TX 75684.

GERMPLASM PENDING RELEASE
Virus Resistant White Clover

A white clover germplasm with resistance to peanut
stunt virus (PSV) was developed cooperatively by
the Sojth Carolina, Mississippi, North Carolina
and Georgia Agricultural Experiment Stations and
USDA-ARS. This germplasm was developed from 95
elite white clover clones from the white clover
breeding programs at Clemson, North Carolina State
and at VPI&SU, Blacksburg, VA. Of the 95 elite
clones, 44 were identified as resistant to PSV
after field testing in South Carolina,

North Carolina, Mississippi and Georgia. A seed
increase was made of the 44 clones in Washington.
Six kg of seed was produced and will be available
when the release is approved. Requests for seed
should be directed to G. A. Pederson, Mississippi
State, MS.

Drought Tolerant Whij^ Clover

Evaluation of drought-tolerant white clover clones
has been completed (6,7). Synthetics made from
polycross progenies of 22 clones selected for
drought tolerance were evaluated for four years in
white clover variety trials. Forage yield and
persistence of the synthetics exceeded the 'Regal'

26

and 'Tillman' checks in the second, third, and
fourth years of testing. Drought-tolerant synthe-
tics had significantly less peanut stunt virus
disease (PSV) than Regal and Tillman. Selection
for PSV resistance apparently occurred con-
currently with selection for drought tolerance.
Preliminary results indicate tolerance to selected
populations of the southern root-knot nematode is
also present in this germplasm. A seed increase
from the 22 clones has been made in preparation
for a germplasm release. Seed will be available
from G. A. Pederson, Mississippi State, MS when
the release is approved.

Elite Crimson Cl_over Inbred l^i_nes_

Ten elite crimson clover inbred lines have been
developed through recurrent selection. Criteria
for selection were maintenance of vigor following
inbreeding; adequate seed and forage production;
and absence of disease symptoms. These elite
lines were identified as superior following
polycross testing in the field. Recently, these
lines contributed to identification of root-knot
nematode tolerance in the Florida clover breeding
program (15). A seed increase is in progress prior
to a germplasm release in 1935.

GERMPLASM UNDER DEVELOPMENT
Res i s tance to Fungal Di_seases

The principal objectives of host-plant resistance
research on fungal diseases are 1) identification
of diseases that infect forage legume species;

2) determination of how these diseases limit pro-
ductivity, stand longevity and survival; 3) eva-
luation of environmental conditions and their
relationship to disease epi phytotics ; and 4) deve-
lopment of disease resistant germplasm.

Four previously unidentified diseases of forage
legumes have been identified and documented for
the first time in the Southeast. These include
Phytophthora root rots of arrowleaf and crimson
clovers (11), a Fusari urn wilt of crimson clover

(12) , a Cercospora leaf and stem disease of sub-
terranean clover, and a noninfectious disease
(internal crown breakdown) of arrowleaf clover.
Phytophthora diseases of arrowleaf clover were
shown to be more severe when plants were also
infected by a common virus (3, 14). The life
cycle of the Sclerotinia pathogen of crimson and
other annual clovers has been clearly documented

(13) .

Research is in progress to evaluate effects of the
Cercospora disease on seed production and seed
quality of subterranean clover, and to evaluate
management practices for control of the
Sclerotini a disease of crimson clover.

Inbred lines of crimson clover with high levels of
resistance to Fusari urn wilt and moderate
resistance to Phytophthora root rot have been
developed (12). These will be combined in the
future to provide new disease-resistant germplasm
or cultivars. Screening for resistance to
Phytophthora root rot of arrowleaf clover will be
continued.

Resistance To The Clover Head Weevil i^n ^ri_^son
Clover

Resistance to the clover head weevil, Hypera meles
Fab. has been identified in crimson clover inbred
lines. Successful screening of clover for insect
resistance is dependent on the capability for pro-
ducing selection pressure through uniform infesta-
tion of candidate plant material. A reliable
technique for ensuring a seasonal source of head
weevils has ')een developed (2). The technique
involves use of a motorcycle mounted collection
net that collects weevils with efficiency about 10
times greater than hand held sweep nets. The
system is capable of collecting overwintered adult
weevils, later instar larval stage, and spring
generation adults. The impact of the apparatus is
significant since it allows collection of suf-
ficient insects for host plant resistance studies
during the very short (4 week) seasonal period
during which these insects are available for
study. The system has also proved valuable for
collection of other clover pests and beneficial
insects for scientific study.

Aphid Resistance i_^n £rjmson Clover

Selections have been made for aphid resistance in
crimson clover. Open-pollinated populations were
screened for resistance to Acyrthosiphon PTSum
Harris and Aphis craccivora Koch. Inbred lines
with apparent resistance have been identified and
increased. These lines will be retested to con-
firm resistance prior to a germplasm release.

Resistance to Root-Knot Ne^matodes

Studies have been initiated to determine the popu-
lation dynamics and damage potential of root knot
nematodes on annual and perennial clovers under
field conditions. Screening of elite clover
germplasms for resistance is in progress and will

27

be expanded to include both annual and perennial
species. The pathogenic variation of root-knot
nematodes on several white clover genotypes is
being determined.

GERMPLASM ENHANCEMENT TECHNIQUES
Tissue Culture

Utilization of tissue culture techniques for crop
improvement ultimately depends on successful plant
regeneration. Many different culture conditions
and media have been used to achieve plant rege-
neration in Tri fol ium species making efficient
utilization of these procedures by other
researchers difficult. Evaluation of four culture
media for callus initiation and production of
crimson, arrowleaf, white, and kura clovers, and
development of procedures for plant regeneration
via somatic embryo-genesis for the four Trifol ium
species has been completed (10).

For the first time, crimson clover plants have
been regenerated from tissue culture via somatic
embryogenesis . All regenerated plants to date are
fertile with the normal chromosome number.
Plantlets of arrowleaf clover have also been rege-
nerated via somatic embryogenesis though none have
survived to maturity. White clover and kura
clover have formed proembryos although no ger-
mination has occurred. This study is the first
step toward utilization of tissue culture tech-
nology in improvement of these clover species.

Screening for Resistance to Fescue
Allelopathic Effects

A new technique was developed to test the allelo-
pathic effects of tall fescue leaf extracts on
white clover (9). White clover genotypes have
been identified which show no reduction in ger-
mination or root growth and plants within species
differ in their response to allelopathic com-
pounds. This provides the basis for selecting
white clover that can tolerate tall fescue allelo-
pathy during initial stand establishment.

Hybr idoma Biotechnology and_ Forage
Legume Vijius Identif icati on

Hybridoma biotechnology is being used in coopera-
tive forage legume virus research involving the
Forage Research Unit of the Agricultural Research
Service, U. S. Department of Agriculture, the
Department of Plant Pathology and Weed Science,

and the College of Veterinary Medicine,

Mississippi State University. Over 2300 hybrido-
mas have been produced and tested in search of
hybridoma cell lines which produce monoclonal
antibodies useful in detection and identification
of bean yellow mosaic virus (3YMV) and clover
yellow vein virus (CYVV) (8). These viruses cause
important diseases of clovers and other Forage and
food legume crops. The hybridomas were formed by
fusion of mouse tumor cells, called tnyelomas, with
antibody-producing spleen cells from mice immu-
nized with purified virus. The hybrid cells
carried the ability to grow and divide in culture
(from the myeloma) and the ability to produce spe-
cific antibodies (from the spleen cell). The
hybridomas were tested to identify those which
secreted antibodies specific for BYMV and CYVV.
Selected hybridomas v/ere cloned to produce
cultures derived from single cells. Antibodies
secreted by single-cell clones are called monoclo-
nal antibodies. Thirty-eight hybridoma clones
were selected for monoclonal antibody production.
Some of the monoclonal antibodies produced so far
are specific to BYMV or CYVV while others react to
varying degrees with both viruses. This suggests
that while these viruses contain some antigenic
determinants (epitopes) which are virus strain
specific, they also share several common epitopes.

This technology offers several advantages over
conventional antibody production methods which use
serum obtained from the blood of iinmunized ani-
mals. Unlike antibodies obtained from immune
serum, monoclonal antibodies from a single cell
line are identical in reactivity and specificity,
may be produced in laboratory tissue cultures
rather than in live animals, and the hybridomas
may be stored in liquid nitrogen for indefinite
periods. Therefore, these hybridomas provide vir-
tually inexhaustible and consistently uniform
sources of antibodies for Future research. By
studying the reactions of BYMV and CYVV with a
panel of several monoclonal antibodies, each with
slightly different specificity and reactivity, the
relationship between these viruses can be more
precisely defined, providing basic information on
virus structure and taxonomy, and improving
disease detection and diagnosis capabilities.

SUMMARY

In the U. S., forage legumes have been criticized
for being undependable and unreliable. Much of
this is due to the minimal research effort devoted
to the development of forage legume cultivars with
resistance to major insect pests and diseases.

28

Congress (In press).

Maintaining a legume component in grazing sy-
stems may mean the difference in economic re-
turn to the producer. The margin of profit
may result from a higher quality forage, stimu-
lation of milk flow, higher calf weaning
weights, and higher conception rates. In addi-
tion to these less obvious benefits, a well
nodulated legume adds significant amounts of
nitrogen for the grass component. Considerable
progress has been made in the improvement of
forage legume species in the past two decades.
However, in order to provide forage legumes
that are dependable and reliable, it is imper-
ative that the germplasm development effort
be accelerated to avoid excessive losses from
an inevitable buildup of insect and disease
pests.

Literature Cited

1. Bal tensperger, D. D., K. H. Quesenberry,

R. A. Dunn, and M. M. Abd-Elgawad. 1985.
Root-knot interaction with berseem clover
and other temperature forage legumes.

Crop Sci. 25:848-851.

2. Ellsbury, M. M. and F. M. Davis. 1982.
Front-mounted motorcycle net for mass
collection of clover insects. J. Econ.
Entomol. 75:251-253.

3. Ellsbury, M. M., R. G. Pratt, and W. E.
Knight. 1985. Effects of single and
combined infection of arrowleaf clover
with bean yellow mosaic virus and a
Phytophthora sp. on reproduction and
colonization by pea aphids (Homoptera:
aphidae). Environ. Ent. 14:356-359.

4. Kimbrough, E. L. and W. E. Knight. 1985.
'Bigbee' berseem clover MCES Info. Sheet.

2 pp.

5. Knight, W. E. 1985. Registration of
Bigbee berseem clover. Crop Sci. 25:
571-572.

6. Knight, W. E. and M. R. McLaughlin. 1985.
Apparent resistance to peanut stunt virus
disease in white clover germplasm select-
ed for drought tolerance. Agron. Ab-
stracts, p. 60.

7. Knight, W. E., C. M. Rincker, M. R.
McLaughlin, and N. C. Edwards. 1985.
Evaluation of drought tolerant white
clover germplasm. Proc. So. Branch
ASA, Vol. 12: p. 2.

8. McLaughlin, M. R., S. W. Scott, and A. J.
Ainsworth. 1986. Monoclonal antibodies
to clover yellow vein and bean yellow
mosaic viruses. Phytopathology (Abstracts
in press).

9. Pederson, G. A. 1985. Allelopathic ef-
fects of tall fescue on germination and
seedling growth of white clover geno-
types. Proc. XV Int. Grassland

10. Pederson, G. A. 1986. In vitro culture
and somatic embrogenesis of four Trifol ium
species. Plant Sci. (In press) .

11. Pratt, R. F. 1981. Morphology, pathogeni-
city, and host range on Phytophthora mega-
sperma , £. erythroseptica, and £. parasi -
tica from arrowleaf clover. Phytopathology
71:276-282.

12. Pratt, R. G. and W. E. Knight. 1986.
Resistance to Fusarium wilt in selected
inbred lines of crimson clover. Crop
Sci. 26.

13. Pratt, R. G. and W. E. Knight. 1982.
Formation of apothecia by sclerotia of
Sclerotinia trifol iorum and infection of
crimson clover in the field. Plant Di-
sease 66: No. 11, pp. 1021-1023.

14. Pratt, R. G., M. M. Ellsbury, 0. W. Barnett,
and W. E. Knight. 1982. Interactions of
bean yellow mosaic virus and an aphid
vector with Phytophthora root diseases in
arrowleaf clover. Phytopathology 72:
1189-1192.

15. Quesenberry, K. H., D. D. Bal tensperger ,
and R. A. Dunn. 1986. Screening Trifol ium
spp. for response to Meloidogyne spp. Crop
Sci. 26:61-64.

16. Smith, G. R. and W. E. Knight. 1984.
Inheritance of ineffective nodulation in
crimson clover. Crop Sti. 24:601-604.

17. Smith, G. R. and W. E. Knight. 1986.
Registration of CHI-1 crimson clover germ-
plasm. Crop Sci . 26.

29

BREEDING OF SERICEA LESPEDEZA (Lespedeza cuneata
(DUMONT) G. DON.) IN ALABAMA. A HISTORICAL
OUTLOOK.

Jorge A. Mosjidis^

PALATABILITY AND TANNIN

Sericea lespedeza, a non-bloating legume, is
one of the few summer perennial legumes well
adapted to the large areas of marginal land
found in the Southeast. It is used as a
forage crop and in soil conservation.

Early work on this plant indicated it had
low palatability and digestabil ity (Clarke,

Frey, and Hyland 1939). It was generally
thought that the high content of tannins of
sericea lespedeza was the cause of this problem.
Not until 1953 did Wilkins, Bates, and Henson
demonstrate that tannins had a definite effect on
its palatability. In 1950, the Alabama
Agricultural Experiment Station (AAES), Auburn
University, initiated a breeding program to
improve palatability and nutritive value of this
crop. A free-choice grazing study with steers
(Donnelly 1954) indicated that the most palatable
sericea lines were those that had fine stems and
a content of tannins less than 4%. Forty percent
of the fine-stemmed and low-tannin plants were
heavily grazed. Futhermore, 24 to 28% of the
plants with fine stems and a content of tannins
of 4.0 to 7.5% were heavily grazed. The stem
effect is probably due to the fact that the
xylem of the fine-stemmed plants is less
lignified than that of plants with medium and
coarse stems (Donnelly and Ferry 1957). Later, a
feeding trial with rabbits confirmed that
fine-stemmed sericea plants were more palatable
than coarse-stemmed ones. It was also found that
both types of stems had desirable and undesirable
nutritive characteristics. (Donnelly and Hawkins
1959). Thus, the palatability problems of
sericea plants were ascribed to stem finess and
tannins.

In 1962 the cultivar Serala was released
(Donnelly 1965) by the AAES. A synthetic made up
of six lines, has finer, more pliable stems,
more stems per plant and does not become as
coarse or woody as commonly grown strains of
sericea. It has a high content of tannins. The
yield of Serala was as good or better than the
cultivars commonly used at the time (Donnelly
1963).

A mutation breeding program in cooperation
with the University of Tennessee - Atomic Energy
Commission Agricultural Research Program at Oak
Ridge, Tenn., was started in 1957. A mutant was
selected and released as a cultivar that could be
used as a forage crop as well as on highway
rights-of-way and in soil conservation areas. It

Department of Agronomy and Soils, Auburn
University, Alabama Agricultural Experiment
Station, Auburn AL 36849

was named Interstate. The cultivar is short
growing, uniform in height, profusely branched,
fine stemmed, and with a high content of tannins.
It also has good seedling vigor and produces more
early herbage than Serala (Donnelly et al . 1970;
Donnelly 1971).

Sources Of Variation of The Content of Tannins

Early work on the factors that affect the content
of tannins of sericea plants had indicated that
tannins did not remain constant as the season
advanced (Clarke, Frey, and Hyland 1939; Stitt
and Clarke 1941). Stitt (1943) found genetic
differences in the content of tannins of sericea.
But, he also suggested that the content of
tannins was related to plant height, number of
shoots, and yield. Later, Stitt, Hyland, and
McKee (1946) found that height and seasonal
weather conditions were not associated with
changes in the content of tannins in the sericea
plant. They also found that the amount of
tannins was influenced by soil type and cuttings
made on different dates on the same soil.
Donnelly (1959) demonstrated that the content of
tannins increased as the season advanced. He
suggested that this increment was related to day
temperature and rainfall because day temperature
increased and precipitation decreased during the
season. He also found that tannins did not
decrease later in the season as reported by
Clarke, Frey, and Hyland (1939) and Stitt and
Clarke (1941). Donnelly's data also indicated
that older tissue contains more tannins than
younger tissue. Burns (1966) reported that a
reduction in light intensity by shading plants
lowered the content of tannins. But, shading the
plants confounds temperature and light intensity
effects, so Burn's results were inconclusive.
Recently, Fales (1984) demonstrated that high
temperature increases the content of tannins in
sericea plants. Wilson (1955) reported that
fertilizers and lime had no effect on the levels
of tannins in sericea.

In short, from Still's (1943) and Donnelly's work
(1954, 1959) it was clear that the main source of
variation in the content of tannins of the
sericea plant is the genotype. Temperature was
found to have a secondary effect (Fales, 1984).

Effect of Tannins On The Forage Quality Of

Sericea Lespedeza

Several studies were carried out to determine the
relationship between tannins and various aspects
of the forage quality of sericea lines with high
or low tannins. It was found that sericea
lespedeza leaves have more tannins than stems
(Donnelly and Hawkins, 1959). Leaves of plants
high in tannins have taeen found to have a
digestable dry matter (DDM) only slightly higher
than the stems of plants high in tannins. The
DDM of stems low in tannins was as high as that
of leaves high in tannins (Donnelly and Anthony
1973). It was also found that, on the average,

lines with low content of tannins have more DDM,
crude protein (CP), and digestable protein (DP)
(Donnelly and Anthony, 1969, 1970; Donnelly,

30

Anthony, and Langford, 1971). Thus, it was
concluded that lines low in tannins have a higher
nutritive value than lines high in tannins.
Recently, Donnelly and Anthony (1983) reported
results that indicate that tannins as well as
other factors may affect digestible dry matter.

There are a few reports concerning the reasons for
the poor quality of sericea forage induced by the
presence of tannins. Smart et al . (1961) found
that a water-soluble extract from sericea
inhibited rumen cellulase. This result was
confirmed by Lyford, Smart and Bell (1967). They
also indicated that the inhibitory material
extracted from sericea forage is responsible in
part for the reduced digestibility of this forage
crop. In 1963, Mandels and Reese suggested that
plants use inhibitors of cellulase to protect
themselves from invasion by fungi. Thus, it was
reported that leucoanthocyanins (a kind of
tannin) may inhibit fungal growth (Robinson
1975). These statements were prophetic with
regard to the results of breeding aimed at
reducing all types of tannins in sericea.
Furthermore, Sarkar, Howarth, and Goplen (1976)
reported that procyanidin (Rf 0.26 to 0.28) may
be the type of tannin that is likely to be the
cause of reduced digestibility and low
palatability of sericea forage.

In short, tannins probably reduce the forage
quality of sericea due to an inhibition of rumen
cellulase. However, not all tannins are
undesirable. Some tannins may provide the plants
with protection to fungal disease. Hence, it
would be more judicious to select more palatable
plants by reducing or eliminating the undesirable
tannins that seem to be associated with
antinutritive properties, while retaining those
with anti bloating properties and those that
protect plants from fungi attacks. We also need
more information on the types of tannins present
in sericea and their association with anti-
nutritive properties. Furthermore, simple and
inexpensive tests to identify the undesirable
tannins would be needed in such a breeding
program.

BREEDING EOR A SERICEA LOW IN TANNINS

In 1955, the sericea breeding program of the
Alabama Agricultural Experiment Station, Auburn
University, received the line low in tannins
Beltsville 23-864, developed by AR-SEA-USDA.

This line is also low in vigor, stemmy, light
green in color, and generally undesirable
(Donnelly and Anthony, 1980). The first crosses
involving this line and lines high in tannins
were made in 1959. Large nurseries of sericea
lines low in tannins were planted. In 1969, a
severe attack of Rhizoctonia sp. damaged the
plants. From about 6,000 lines, 82 disease-free
plants were selected. These plants were also low
in tannins (Donnelly, 1983b). However, it was
found that reaction of the lines to the disease
is strongly influenced by the environment. Thus,
rating of the plants for tolerance to Rhi zoctonia
in two consecutive years had a correlation
coefficient of only 0.74. Also a high lines x

locations interaction has been reported (Donnelly
1983a, b). Thus, the breeding program for low
tannins had an additional objective, namely,
tolerance to Rhizoctonia. Out of this selection
work came the sericea cultivar AU Lotan released
in 1980 by AAES, Auburn University. AU Lotan
contains an average of 50% less tannins than a
normal sericea plant. At hay stage, digestible
dry matter is 27% higher and crude protein is 7%
higher than a cultivar high in tannins (Donnelly,
1981). However, the yield is lower than Serala.
AU Lotan has had a yield that ranges between 58%
and 98% of Serala with an average of 75% in seven
environments (two years in two locations and
three years in one location). It has a good
resistance to Rhizoctonia sp. and to the root
knot nematode Mel oidogyne incognita acrita.

NEMATODE RESISTANCE

A second problem observed in sericea plants was
that the stand of some lines thinned out or died
out. It was found to be related to sensitivity
to root knot nematodes (Donnelly and Minton
1968). Several lines of sericea were found to be
highly resistant to Meloidoqyne incognita
incognita, M. incognita acrita, and ^ hapla
(Minton, Donnelly, and Shepherd, 1966).

Resistance to hapla seems to be conferred by 1
or 2 dominant genes (Adamson et al . 1974).

In 1978, two cultivars, Serala 76 and Interstate
76, were released by the AAES, Auburn University
the Georgia Agricultural Experiment Station and
the AR-SEA-USDA. Serala 76 is a synthetic
cultivar made up of 10 lines resistant to
Meloidogyne incognita incognita and RL incognita
acrita. Four of the 10 lines are also resistant
to hapl a . Serala 76 is a fine-stemmed,
tall-growing cultivar similar to Serala in stem
type and height (Donnelly and Minton, 1979).

Interstate 76 is made up of two lines. It is
resistant to all three of the above mentioned
species of root knot nematodes. Interstate 76 is
a fine-stemmed, leafy, dense cultivar. It is
intermediate between Serala and Interstate in
height and has a more open growth habit than
Interstate. It produces more early herbage than
Serala or Serala 76 which makes it especially
good for soil conservation. It is also a good
forage producer. Both Serala 76 and Interstate
76 are high in tannins (Donnelly and Minton,
1979).

SEEDLING VIGOR

A third problem recognized in this crop was its
slow germination and poor seedling establishment
because the seedlings are weak and compete poorly
with weeds. Logan, Hoveland, and Donnelly (1969)
found an inhibitor of seed germination in the
seed coat of sericea seeds. The germination
experiments were carried out in petri dishes. No
further work was done to relate the presence of
this inhibitor to seed germination and seedling
establishment under conditions where the
inhibitor could be washed away. This line of
work was not further pursued.

31

FUTURE PLANS

The problem of poor seedling vigor in sericea did
not receive much attention in the past. Poor
seedling vigor has a two-fold effect: (1) stand
failure, and (2) poor growth during the year or
establishment. As a consequence of the latter,
plants are not usually cut or grazed during the
first year to allow good establishment. Although
the phenomenon of poor establishment in forage
crops is well documented, few solutions to the
problem have been proposed. Because of the many
factors that can lead to poor establishment, more
research is needed to understand the growth and
development of sericea in order to carry out a
successful breeding program on this matter.
Nevertheless, the few examples available of
breeding programs that have succeeded in
improving plant establishment (Townsend 1985),
give enough guidelines to initiate a breeding
program for seedling vigor in sericea that can be
modified according to the results obtained on the
experiments designed to understand this plant's
growth.

Our first priority will be the screening and
selection of sericea for greater dry matter
production and faster early growth rates.

Evidence that such a possibility exists comes
from the report by Clements and Latter (1973).
They succeeded in selecting Phalaris tuberosa for
heavy seedlings.

Literature Cited

Adamson, W.C., E.D. Donnelly, N.A. Minton and
J.D. Miller. 1974. Inheritance of resistance
to Meloidogyne hapla in Lespedeza cuneata.
The Journal of Heredity 65:365-368.

Burns, R.E. 1966. Tannin in sericea lespedeza.
Ga. Agric. Exp. Stn. Bull. N.S. 164.

Clarke, I.D., R.W. Frey, and M.C. Hyland.

1939. Seasonal variation in tannin content of
lespedeza sericea. J. Agric Res. 58:131-139.

Clements, R.J. and B. Latter. 1973. Responses
to selection for seed weight and seedling
vigor in Phalaris. Aust. J. Agric. Res.
25:33-44.

Donnelly, E.D. 1954 Some factors that affect
palatability in sericea lespedeza, L. cuneata.
Agr. J. 46:96-97.

Donnelly, E.D. 1959. The effect of season,
plant maturity, and height on the tannin
content of sericea lespedeza, L. cuneata. Agr.
J. 51:71-73.

Donnelly, E.D. 1963. Serala- A new sericea

variety. Auburn Univ., Agr. Exp. Stn. leaflet
70 p. 1-4.

Donnelly, E.D. 1965. Serala sericea. Crop Sci.
5:605.

Donnelly, E.D. 1971. Registration of Interstate
sericea lespedeza. Crop Sci. 11:601-602.

Donnelly, E.D. 1981. Registration of AU Lotan
sericea lespedeza. Crop Sci. 21:474

Donnelly, E.D. 1983a. Breeding low-tannin
sericea. I. Selecting for resistance to
Rhizoctonia sp. Crop. Sci. 23:14-16.

Donnelly, E.D. 1983b. Breeding low-tannin

sericea. II. Effects of Rhizoctonia foliar
blight on vigor and seed yields. Crop. Sci.
23:17-19.

Donnelly, E.D. and W.B. Anthony. 1969.
Relationship of tannin, dry matter
digestibility and crude protein in sericea
lespedeza. Crop Sci. 9:361-362.

Donnelly, E.D. and W.B. Anthony. 1970 Effect of
genotype and tannin on dry matter
digestibility in sericea lespedezea. Crop
Sci. 10:200-202.

Donnelly, E.D. and W.B. Anthony. 1973.

Relationship of sericea lespedeza leaf and
stem tannin to forage quality. Agr. J.
65:993-994.

Donnelly, E.D. and W.B. Anthony. 1980. New
Auburn sericea variety 'AU Lotan', low tannin,
nutritious forage. Auburn Univ., Agric. Exp.
Stn. Highlights of Agric. Res. Vol . 27, No 2,
Summer 1980.

Donnelly, E.D. and W.B. Anthony. 1983. Breeding
low-tannin sericea. III. Variation in forage
quality factors among lines. Crop, Sci,
23:982-984.

Donnelly, E.D., W.B. Anthony, and J.W. Langford.
1971. Relationships in low- and high-tannin
sericea lespedeza under grazing. Agr. J.
63:749-751.

Donnelly, E.D., R. Dickens, D.G. Sturkie, and
J.D. Miller. 1970, Interstate sericea
lespedeza. New variety for a special use.
Auburn Univ., Agric. Exp. Stn. Highlights of
Agric. Res. Vol. 17, No 2, Summer 1970.

Donnelly, E.D. and J.F. Ferry. 1957. An

analysis of the anatomy of three stem types of
sericea lespedeza, ^ cuneata. Proc. Assoc.
Sou. Agri . Workers p. 59.

Donnelly, E.D. and G.E. Hawkins. 1959. The

effects of stem type on some feeding qualities
of sericea lespedeza, cuneata, as indicated
in a digestion trial with rabbits. Agr. J.
51:293-294.

Donnelly, E.D. and N.A, Minton. 1968.

Nematode-resistant sericea, now possible.
Auburn Univ., Agric. Exp. Stn. Highlights of
Agric. Res. Vol 15, No 2, Summer 1968.

Donnelly, E.D. and N.A. Minton, 1979.

Registration of Serala 76 and Interstate 76
sericea lespedeza. Crop Sci. 19:929.

Fales, S.L. 1984. Influence of temperature on

32

chemical composition and jji vitro dry matter
disappearance of normal- and low-tannin
sericea lespedeza. Can. J. Plant Sci.
64:637-642.

Logan, R.H., C.S. Hoveland, and E.D. Donnelly.
1969. A germination inhibitor in the seed
coat of sericea (Lespedeza cuneata (Durmont)

G. Don). Agr. J. 61:256:266.

Lyford, S.J., W.W. G. Smart, amd T.A. Bell. 1967.
Inhibition of rumen cellulose digestion by
extracts of sericea lespedeza. J. of Animal
Sci. 26:632-637.

Mandels, M. and E.T. Reese. 1963. Inhibition of
cellulases and beta-glucosidases. Iji Reese,
E.T. (ed). Advances in enzymic hydrolisis of
cellulose and related materials, p. 115-157.
Pergamon Press Inc., New York.

Minton, N. A. E.D. Donnelly and R.L. Shepherd.
1966. Reaction of varieties and breeding
lines of sericea lespedeza to five root knot
nematode species. Phytopathology 56:180-182.

Robinson, T. 1975. The organic constituents of
higher plants. 3rd ed. Cordus Press. Mass.
347 p.

Sarkar, S.K., R.E. Howarth, and B.P. Goplen.

1976. Condensed tannins in herbaceous
legumes. Crop. Sci. 16:543-546.

Smart, W.W.G., T.A. Bell, N.W. Stanley, and W.A.
Cope. 1961. Inhibition of rumen cellulase by
an extract from sericea forage. J. of Dairy
Sci. 44:1945-1946.

Stitt, R.E. 1943. Variation in tannin content
of clonal and open-pollinated lines of
perennial lespedeza. J. Am. Soc. Agr.
35:944-954.

Stitt, R.E. and I.D. Clarke. 1941. The relation
of tannin content of sericea lespedeza to
season. J. Am. Soc. Agr. 33:739-742.

Stitt, R.E., H.L. Hyland, and R. Mckee. 1946.
Tannin and growth variation of a sericea
lespedeza clone in relation to soil type. J.
Amer. Soc. Agr. 38:1003-1009.

Townsend, C.E. 1985. Recurrent selection for
improved seed germination, seedling
elongation, and seedling emergence in cicer
milkvetch. Crop Sci. 25:425-429.

Wilkins, H.L., R.P. Bates, and P.R. Henson.

1953. Tannins and palatability in sericea
lespedeza, L. cuneata. Agr. J. 45:335-336.

Wilson, C. 1955. The effect of soil treatments
on tannin content of lespedeza sericea. Agr.
J. 47:83-86.

33

TREFOILS FOR THE SOUTHEAST

1 2
J. F. Pedersen and C. S. Hoveland

Birds foot trefoil (Lotus corniculatus
L.)> a native of Europe and parts dl
Asia, has been commonly grown in the
central and northern United States for
many years (Grant and Martin, 1985).

It has not been regarded as being
adapted in the Southeast. However,
the recent releases of 'AU Dewey',

GA-1 , and 'Fergus' have extended the
adaptation range into the upper
portions of the Southeast.

The first southern trefoil cultivar,
Fergus, was released in 1980 by the
Kentucky Agricultural Experiment
Station (Taylor and Templeton, 1985).
Fergus was selected from a mixture of
'Empire' and a French introduction
after 15 years of natural selection
under grazing in Woodford County,
Kentucky. It is the only one of the
three cultivars with seed currently
available commercially.

Both AU Dewey and GA-1 were released
in 1985. AU Dewey was released by the
Alabama Agricultural Experiment
Station (Pedersen et al., 1986). It
was developed from open pollinated
seed of 13 plants selected from two
Yugoslavian plant introductions.
Selection criteria were rhizomatous
nature, prostrate growth habit, and
general vigor and adaptation in
central Alabama.

GA-1 was released by the Georgia
Agricultural Experiment Station as a
germplasm (Fales et al. 1986).

Although GA-1 was not released as a
named cultivar per se, seed is already
being increased in the northern
United States. It was developed from
crosses between a Brazilian
introduction and 'Kimey', 'Granger',
and 'Empire'. It arises from 15
clones selected from approximately
2000, after 7 years of natural
selection at Experiment, Georgia.

The advantages and disadvantages of
trefoil in the South were outlined by
Hoveland et al. (1982). "Trefoil has
several advantages: (1) tolerant of
soil acidity, (2) drought tolerance,

(3) not damaged by alfalfa weevil, (4)
reseeds well from hard seed, (5) h i^
quality forage, and (6) does not cause

Agronomy and Soils Department, Auburn
University, AL 36849. ^Agronomy
Department, University of Georgia,
Athens, GA 30602.

bloat in cattle. Disadvantages are :

(1 ) indeterminate flowering and seed
shattering, generally resulting in low
seed yields, and (2) susceptibility to
crown and root-rotting diseases in the
southern United States. In addition,
northern trefoil varieties generally
have poor seedling vigor and are slow
to establish."

A forage species posessing all the
above advantages is certainly needed
in the South, especially if the above
disadvantages can be rectified. Seed
production problems in the South have
been addressed by moving production
northward to traditional
trefoil-growing areas. Other problems
with the species appear to have been
overcome, at least in part, by the
selection programs described.

Results of seed germination tests of
several trefoil cultivars under stress
conditions are shown (tables 1 and 2).

Table 1. Seed germination at two
temperatures after 16 days.

Seed germination

Variety 68 F 86 F

AU Dewey

1

90 a*

1

79 a

Fergus

92 a

73 ab

Viking

81 ab

63 be

Dawn

79 ab

56 c

Empire

74 b

40 d

*Means within a column marked with
the same letter are not significantly
different at the .05 level of
probability .

Table 2. Seed germination after 12
days as affected by simulated drought
using a polyethylene glycol solution
at 68°F.

Seed

germination

Variety

0 bars
7

-3 bars
7

Fergus

98°a*

98 a

AU Dewey

95 ab

85 ab

Viking

82 be

75 be

Dawn

82 be

70 c

Empire

76 c

45 d

*Means within a column marked with the
same letter are not significantly
different at the .05 level of
probabil ity .

The improved germination of AU Dewey
and GA-1 at high temperatures and
under drought conditions common to the
South is apparent, and should
contribute to better stands and more
effective reseeding.

34

Yield of these trefoils in monocultures
and in grass mixtures has been very
good without the use of nitrogen
fertilizers (Hoveland and Pales, 1985).
Trefoil yields and total yields of the
mixtures are shown for a three year
study conducted in northern Georgia
(table 3 ) .

Table 3. Yields of birdsfoot trefoil
cultivars in monoculture and in
association with grasses in the
Piedmont area of Georgia, 3-year
average .

Trefoil

Grass

Dry matter yield

Tretoii

Mixture

lb.

/A

AU Dewey

-

7607 a*

7607 a

GA-1

-

6143 b

6143 b

Fergus

-

5750 c

5750 c

Dawn

5268 d

5268 d

AU Dewey

TF^

3786 cd

6714 ab

GA-1

TF

3295 de

6393 b

Fergus

TF

2991 e

5527 c

Dawn

TF

2071 f

5589 c

AU Dewey

OG

4232 c

6527 ab

GA-1

OG

4179 c

6063 b

Fergus

OG

2839 e

5036 d

Dawn

OG

3089 d

5036 d

*Means within a column marked with the

same letter are not significantly
different at the .05 level of
probability .

TF = 'Kentucky 31' tall fescue and
OG = 'Hallmark' orchardgrass

In this test, AU Dewey and GA-1 clearly
outperformed Fergus and °Dawn', the
northern check variety. High trefoil
yields in grass mixtures show that this
reseeding perennial legume may have a
place in tall fescue (Festuca
a rund in ac e a S ch r eb . ) and orchardgrass
(Dactylis g, lomerata L. ) pasture
renovation.

As would be expected from the above,
and frcm other grazing trials, cattle
performance on southern trefoil /grass
pastures is very good (table 4).
Althou^ total gain per acre was not as
high as with n itrogen- fer til ized tall
fescue because of reduced grazing days,
high average daily gains (ADG) with AU
Dewey mixtures compensated for reduced
pasture days (Hoveland et al. 1985).

Steer production on pure stands of GA-1
birdsfoot trefoil nearly equalled that
on 'Apollo' alfalfa (Medicago sativa
L.) in a three year study in central
Georgia (Table 5). Although stocking
rate was higher on the alfalfa, the
longer grazing season (28 days) on the

Table 4. Steer performance on grass +
nitrogen and grass + AU Dewey birdsfoot
trefoil in North Alabama, 2-year
average .

Pasture

Grazing
days/ acre

Gain/

acre

ADG

TF^ + 150 lb.

no.

lb.

lb.

N 322 a

681 a

2.1

TF + AU Dewey

228 b

550 b

2.4

OG + AU Dewey

164 c

450 c

2.7

’''Means within a column marked with the
same letter are not significantly
different at the .05 level of
probab il ity .

TF = Kentucky 31 tall fescue and
OG = Hallmark orchardgrass

trefoil pastures compensated for fewer
animals. The ADG ' s were high with both
species. It should be pointed out that
thinning of trefoil stands occurred at
this location although natural
reseeding was good. There is some
question whether trefoils are adapted
this far south when competition from
warm season perennial growth can be
severe.

Table 5. Steer performance on Apollo
alfalfa and GA-1 birdsfoot trefoil in
central Georgia, 3 year average.

Alfalfa

Trefoil

Days grazing

105

133

Steers/ acre

1.5

1.1

ADG, lb.

1.9

1.8

Gain/acre, lb.

283

243

During the first year of a grazing
study in north Georgia comparing AU
Triumph tall fescue + nitrogen
fertilizer to AU Triumph + Fergus
birdsfoot trefoil, results were similar
to the Alabama study (Table 6). This
study, however, also included an
economic analysis of the treatments.

The net return to land, labor, and
management of the fescue + trefoil was
double that of the fescue + nitrogen
fertil izer .

After forage researchers complete their
task of developing and testing new
cultivars, one major question still
remains. Will they work on the farm ?
Results of early demonstrations are
encouraging. This response from an
Alabama cattleman with demonstration
plots of Fergus and AU Dewey supports
our optimism. "If seed of trefoil was
available, I would buy and plant more

of it There are many different

situations on different cattle farms
and I believe that trefoil has a place
on at least some of them."

35

Table 6. Steer performance and
economic returns on AU Triumph + 120
lb. N/acre and AU Triumph + Fergus
birds foot trefoil in north Georgia,
1985.

AU Triumph
+N +Trefoil

Dates grazed

-- 3/12-

8/1 --

Steer days/acre

266

197

ADG, lb.

1.7

2.1

Gain/acre, lb.

457

435

Cost/acre, $

58

33

Cost/lb. gain, $

0.2

0.2

Net return, $

44

89

Literature Cited

Fales. S. L., D. G. Cummins, and R. E.
Burns. 1986 Registration of Georgia
1 birds foot trefoil germplasm. Crop
Sci. 26:205.

Grant, W. F. and G. C. Martin. 1985.
Birdsfoot Trefoil, p 98-117. In M.
E. Heath, R. F. Barnes, and D. S.
Metcalfe, eds. Forages-the Science
of Grassland Agriculture 4th ed .

Iowa State Univ. Press. Ames.

Hoveland, C. S. and S. L. Fales. 1985.
Mediterranean-gerraplasm trefoils in
the southeastern USA Piedmont. Proc.
XV International Grass. Congr.

Kyoto, Japan.

Hoveland, S. C., R. L. Haaland, R. R.
Harris, and J. A. McGuire. 1982.
Birdsfoot trefoil in Alabama. Ala.
Agric. Exp. Stn. Bui. 537.

Hoveland, C. S., R. R. Harris, R. L.
Haaland, J. A. McGuire, W. B.
Webster, and V. H. Calvert. 1985.
Birdsfoot trefoil-grass pasture for
steers in the Tennessee Valley. Ala.
Agric. Exp. Stn. Bui. 567.

Pedersen, J. F., R. L. Haaland, and C.
S. Hoveland. 1986. Registration of
AU Dewey birdsfoot trefoil. Crop
Sci. 26: (in press)

Taylor, T. H. and W. C. Templeton.

1985. Registration of Fergus
birdsfoot treefoil. Crop Sci.

25:712.

36

A NEW LOOK AT ROSE CLOVER
G. R. Smith^

INTRODUCTION

Rose clover (Trifolium hirtum All.) is a winter
annual forage legume that produces a high
percentage of persistent hard seed and is
adapted to a broad soil pH range. Other
attributes of rose clover include drought
tolerance and very few pest problems identified
to date. Limitations of current varieties of
rose clover are: intolerance of poorly drained,
wet soils; early maturity; and low productivity
in the U.S. Southern Region. 'Kondinin' and
'Hykon', both developed in Western Australia,
are the only certified rose clover varieties
currently available. R. M. Love (1) has
reviewed rose clover with emphasis on adaptation
and production in California.

Reliable reseeding of annual clover is dependent
on the interaction of climate, management, hard
seed percentage and hard seed persistence (rate
of softening) (2). Williams and Elliot (5)
investigated the decline in hard seed percent of
rose, subterranean (Trifolium subterraneum L.),
and crimson (Trifolium incarnatum L.) clover
under several environments in California.

Averaged across five sites, four months after
seed maturity, the hard seed percentage of 'Mt.
Barker' sub, 'Common' crimson and 'Wilton' rose
clover dropped to 8.4, 5.8 and 97.6%,
respectively (5) . The persistence of rose clover
hard seed helps insure seed survival over
seasons and years, thus increasing the
reliability of this annual clover.

Objectives of the rose clover breeding program
at Overton are: 1) identification of highly
productive, full season (late maturing + good
early growth) rose clover germplasm adapted to
Texas; 2) maintenance of persistent hard seed
and pest resistance traits in new germplasm.

MATERIALS AND METHODS

Initial Selection and Evaluation

Three hundred and eighty seedlings of rose
clover were transplanted to a spaced-plant field
nursery on November 15, 1982. 'Wilton' rose
clover and plant introductions 287973, 311483,
287975 and 311485 were the germplasm base for
this nursery. Soil pH was 6.8 (0-6 inches).

Soil test ratings of phosphorus and potassium
were low and very low, respectively. Prior to
transplanting, 450 Ibs/acre of 0-20-20 were
applied to the Sawtown fine sandy loam soil. In
early January 1983, plants showing winter freeze
injury (23% of the nursery) were removed. In
March and April, the remaining plants were rated
for maturity and forage potential. Based on

]_/Assistant professor, Texas Agricultural

Experiment Station, Overton.

these ratings, 19 rose clover lines were
identified for further evaluation.

These 19 selections and their parental lines
were planted at Overton in 3 ft rows on October
26, 1983. Seeding rate was 0.5 g/row of
inoculated (Nitragin type WR with Pelgel) seed.
Experimental design was a randomized complete
block with two replications. Two evaluators
rated these rose clover lines for stand,
maturity and forage potential in March and April
1984. Ten superior lines were identified. At
maturity, seed were harvested and a subsample
was hand-cleaned for hard seed determination.
Percent hard seed was measured by placing 200
seed from each line on moist germination paper
in petri dishes (50 seed/dish, 4 dishes). The
germination paper was checked daily and kept
moist with deionized water. After ten days
unimbibed seed were counted as hard seed.

Multi-Location Evaluations

Observation plots of the ten experimental rose
clover lines and two check varieties, Kondinin
and Hykon, were established in late October or
early November 1984 at 8 Texas locations,
including Overton, Dallas, Temple, College
Station, Yoakum, Angleton, Beeville, and
Weslaco. Nitragin inoculant (type WR) and six
grams of seed per entry were provided which was
sufficient to plant three replications of 12 ft
rows at 15 lb seed/ac. Notes were taken at each
location for winter damage, maturity, and forage
potential. Seasonal forage production was
measured at Overton.

RESULTS AND DISCUSSION

Initial Selection and Evaluation

Five hundred and twenty three annual clover
plant introductions were evaluated at Overton in
1976-77 for stand establishment, seedling vigor
and growth rate (4) . From these original plant
introductions rose clover was identified as one
of several clovers with potential for
improvement and use in Texas (3) . This specie
is primarily self-pollinated but the percentage
of outcrossing is enough (5%) for variation to
occur within and among lines.

The final ten selections made from the 1984
seeded rows consisted of 3 lines from P.I.
287973, 4 lines from 311485, 2 lines from 311483
and one line from Wilton. In general, these 10
selections were rated better than the commercial
varieties for vigor or forage potential and were
later in maturity than Hykon or Kondinin (Table
1) . The selections ranged from slightly earlier
to slightly later than the variety Wilton. Hard
seed percentage ranged from 81 to 54 percent for
the selections and 88 to 82 percent for the
commercial varieties. Further testing is in
progress to determine the relative persistence
of hard seed produced by the rose clover
selections and commercial varieties.

37

Multi-Location Evaluations

Relative maturity and forage potential ratings
for each location are shown in Tables 2 and 3.
The frequency and date of notes varied between
locations. To compare across locations, we have
presented the notes taken around mid-April,
where available. Forage potential of the
experimental rose clover lines was rated higher
at most locations than the commercial varieties,
Hykon and Kondinin, which served as checks. The
ratings were reversed at Beeville on notes taken
March 27. This note was one to two weeks
earlier than at other locations and many of the
experimental lines were still in a vegetative
growth stage.

All the experimental lines were later in
maturity than Kondinin and Hykon. At Weslaco,
many experimental lines were earlier than at the
more northern locations. This was probably due
to photoperiod response and higher temperatures.
Late maturity in these experimental lines has
resulted in a late April to mid-May bloom period
at Overton. These lines are later in maturity
than crimson clover, but earlier than arrowleaf
(Trifolium vesiculosum Savi) clover. This trait
should allow a good expression of yield
potential but minimum competition with warm
season perennial grasses.

Severe winter damage at Dallas resulted in
complete stand loss of Kondinin and Hykon and
95% stand loss of line RR-12. Winter kill at
Dallas of the remaining experimental lines
ranged from 30 to 50%. Yoakum reported stand
losses due to cold damage of 15, 13, and 7% for
Hykon, RR-12, and Wilton, respectively. Rose
clover line RR-12 appeared to be the least
winter-hardy of the experimentals evaluated.

At Overton, rose clover production ranged from
2617 to 647 lbs DM/ acre for M-13 and Hykon,
respectively (Table 4) . The highest yielding
experimental rose clover (RM-13) produced 80 and
130% more forage than the checks Wilton and
Kondinin, respectively. Genotype x environment
interaction effects on forage production will be
investigated in more detail next year.

With seed increases from the 1984-85 season,
replicated forage production trials with these
experimental rose clovers were established at
Overton, Dallas, College Station, Angleton,
Beeville, and Yoakum in the fall of 1985. Data
from these experiments will provide more
information concerning the future of rose clover
in Texas.

3. Shipe, E. R., and F. M. Rouquette, Jr. 1980

Evaluation of 52 Trifolium plant intro-
ductions previously selected as having
agronomic potential for East Texas.

TAES, Dept, of Soil and Crop Sci., Dept.
Tech. Rep. 80-6. p. 83-85.

4. Shipe, E. R., and F. M. Rouquette, Jr. 1980

Evaluation of 523 plant introductions of
Trifolium spp. TAES, Dept, of Soil and
Crop Sci., Dept. Tech. Rep. 80-6.
p. 86-91.

5. Williams, W. A., and J. R. Elliot. 1960.

Ecological significance of seed coat
impermeability to moisture in crimson,
subterranean and rose clovers in a
mediterranean-type climate. Ecology
41:733-742.

Literature Cited

1. Love, R. M. 1985. Rose clover. ^ N. L.

Taylor (ed.) Clover Science and
Technology, Agronomy 25:536-545.

2. Salisbury, P. A., and G. M. Holloran. 1983.

Inheritance of rate of breakdown of
seed coat impermeability in subterran-
ean clover. Euphytica 32:807-819.

38

TABLE 1. ROSE CLOVER SELECTIONS, PARENTAL LINES AND CHECKS FROM 1983-84 SEEDED ROWS

1983-84 1982-83 April 26, 1984

Entry Nursery

No .

ID

Origin

Vigor^

Stand"^

w • ^

Maturity

Height^

Hard Seed'

inches

%

17

RH7

311483

4.1

99

2.7

8.5

81.0

18

RJ3

287973

4.4

98

3.0

10.5

59.5

21

RF20

287973

4.1

91

3.0

9.0

70.5

22

R015

287973

4.8

96

3.0

11.5

76.7

23

RD3

311485

4.6

92

2.5

10.0

66.7

24

RD17

311485

4.3

97

3.0

9.5

68.7

26

RM13

311485

5.0

99

3.0

12.0

66.0

27

RM16

311485

4.4

96

2.7

10.5

66.0

13

RR12

Wilton

3.8

92

1.7

5.5

75.2

14

RH18

311483

3.7

81

2.0

7.5

54.5

1

-

Wilton

2.3

45

2.2

4.0

82.7

2

-

Hykon

1.1

56

5.0+

4.5

88.0

3

-

Kondinin

1.4

67

5.0+

6.0

88.2

4

-

287973

4.0

96

2.7

9.0

75.0

5

-

311485

4.3

83

3.0

11.0

75.7

6

-

287975

3.7

89

3.7

8.0

76.5

7

“

311483

3.5

74

3.0

9.0

77.5

5 = vigorous.

leafy plant; 1 = stemy.

low vigor plant (mean of two evaluators and two reps)

Mean of two evaluators and two reps
^1 = vegetative, 5 = full bloom (mean of two reps)

4

Mean of two reps
^Mean of 4 reps

TABLE 2. MATURITY RATING OF EXPERIMENTAL LINES AND COMMERCIAL VARIETIES OF ROSE CLOVER GROWN AT

EIGHT TEXAS

LOCATIONS IN

1984-

85

Line

Overton

College

Station

Beeville

Dallas

Yoakum

Temple

Angleton

Weslaco

RM-16

3.5I

2.0

1.0

2.0

3.0

4.0

3.0

5.0

RR-12

3.0

2.6

4.0

1.0

3.0

2

3.0

5.0

RH-18

3.0

2.0

4.0

2.0

3.0

2

3.0

2.0

RH-7

4.0

2.6

1.0

2.0

4.0

3.0

3.0

5.0

RJ-3

3.5

2.6

4.0

2.0

4.0

3.0

3.0

4.0

RF-20

4.0

2.3

1.0

2.0

4.0

4.0

4.0

2.0

RD-15

3.5

2.3

1.0

2.0

4.0

4.0

3.0

2.0

RD-3

3.0

2.0

1.0

2.0

3.0

3.0

3.0

5.0

RD-17

3.5

2.6

1.0

5.0

4.0

4.0

3.0

5.0

RM-13

4.0

2.3

1.0

5.0

4.0

2

3.0

4.0

Kondinin

5.0

4.3

4.5

3

5.0

5.0

5.0

5.0

Hykon

5.0

4.0

4.5

3

5.0

5.0

5.0

5.0

Note Date

4-18

4-18

3-27

4-25

4-18

4-22

4-19

4-26

^Maturity: :

1 = vegetative

, 2 =

bud,

3 = late bud.

4 = first

color, 5

= full bloom

2

Not included at this location

3

Winter-killed

39

TABLE 3. FORAGE POTENTIAL RATING OF EXPERIMENTAL LINES AND COMMERCIAL VARIETIES OF ROSE CLOVER
GROWN AT SEVEN TEXAS LOCATIONS IN 1984-85

Line

Overton

College

Station

Beeville

Dallas

Yoakum

Temple

Angleton

RM-16

4.9I

4.0

2.0

3.0

4.3

3.8

4.0

RR-12

3.7

3.3

3.5

1.0

2.9

2

4.0

RH-18

4.9

4.0

2.5

3.0

3.7

2

4.0

RH-7

4.4

4.3

2.5

4.0

4.5

3.8

4.0

RJ-3

4.7

3.0

2.5

3.0

3.8

4.0

4.0

RF-20

4.9

4.0

2.5

3.0

4.3

3.3

5.0

RD-15

4.7

3.3

2.5

4.0

3.9

3.3

4.0

RD-3

4.8

4.3

2.0

4.0

4.5

3.5

4.0

RD-17

5.0

4.3

2.5

4.0

4.2

3.3

5.0

RM-13

4.7

3.3

2.5

5.0

4.0

2

5.0

Kondinin

2.9

1.3

4.0

3

3.1

2.5

2.0

Hykon

2.0

1.3

4.0

3

2.5

1.5

2.0

Note Date

4-18

4-18

3-27

4-25

4-18

4-2

4-19

^Forage potential; 1 = poor, 5 = best

2

Not included at this location
^Winter-killed

TABLE 4. FORAGE PRODUCTION OF ROSE CLOVER AT

OVERTON,

TEXAS, 1984

-85

Variety^

Harvest Date

3-26 4-16 5-14

Total

RM-13

824

lbs

1546

DM/ acre

247

2617

RF-20

704

1668

187

2559

a

RD-17

801

1383

214

2398

ab

RM-16

629

1510

163

2302

ab

RR-12

501

1388

309

2198

ab

RJ-3

534

1511

118

2163

ab

RO-15

531

1310

207

2048

abc

RH-18

495

1300

188

1983

abc

RH-7

398

1345

238

1981

abc

RD-3

465

1275

136

1876

abc

Wilton

292

953

215

1460

bed

Kondinin

401

637

87

1125

cd

Hykon

299

315

33

647

d

C.V. = 19.6%

^Yields

followed by

the same

letter

are not

significantly different at the 0.01 level using
the Student Newman-Keuls Multiple Range Test.

2

Entries identified by letter-number combinations
are experimental rose clover lines from the
Overton clover breeding program.

40

THE BENEFITS OP FESCUE PASTURE RENEVVAL
1

James E. Standaert

Tall Fescue is used extensively as pasture in
beef cow-calf production in most Southeastern
States. The discovery of a link between the ex-
istence of a fungus (Acremonium Coenophialum) in
the tall fescue plant and poor animal performance
by animals who consume the plant has led many
producers to consider renewal programs for their
fescue pastures. Such considerations require
knowledge about 1) tested levels of fungus infes-
tation in fescue pastures, 2) the costs of var-
ious renewal programs and 3) the stream of bene-
fits forthcaning from various renewal options.

Fescue pasture renewal may involve merely seeding
a legume into an infested stand, or it may in-
volve totally destroying the stand and reseeding
with fungus free seed with or without legumes.

The establishment costs associated with the in-
troduction of clover or total reseeding are well
known and Include charges for alternative feed
sources for animals during renewal. Cost esti-
mates for various pasture renewal options under
North Carolina conditions are given elsewhere
(Standaert, 1986). The remainder of this report
will be taken up with estimating the benefits to
be gained from renewal of fungus infested fescue
pastures in a cow-calf production setting.

THE BENEFITS OF PASTURE RENEWAL

The benefit of pasture renewal is an avoidance of
the animal symptoms associated with fescue fun-
gus. With renewal cows will presumably yield
more milk, calves will gain faster and breeding
performance may be Improved. For pastures with
low levels of fungus infestation the benefits to
renewal will be small and for those with high
levels the benefits will be large. In this sec-
tion, we attempt to attach specific monetary
values to renewal of pastures with differing
fungus infestation levels.

Since the discovery of the fungus has been so
recent much about how it affects animals is still
unknown. Scientists are now in the middle of
experiments which examine how different levels of
fungus affect level of milk production, level of
calf gain, and level of breeding performance.

Another area in which information is lacking is
the effects of different levels of fescue fungus
infestation on animal consumption of the grass.

Do animals experience poorer performance on grass
with high levels of infestation because they eat
less than they would grass with low levels of
infestation? Or is the poorer performance due to
poorer conversion of that which is consumed? Or
both? These are Important questions because
their answers will help cow-calf operators

1

Department of Economics and Business, N.C. State
University, Raleigh. 27695-8109

plan how their management (i.e. stocking rate,
fertilizer amounts, hay storage) will change
should they decide to renew their pastures. If
most of the problem is a result of poor conver-
sion of feed into beef gain (or milk) then
lowering the fungus level by renewal will mean
little change will be required in stocking rates
if fertilizer amounts remain the same. If how-
ever, most of the problem is a result of an ani-
mals "going off feed", then animals consuming
a renewed pasture will consume more at a faster
pace than if the pasture remains in its infested
state. It is likely that on renewed pastures
stocking rates will be lower, or the grazing
season will be shorter, or supplaments to pas-
ture will need to be supplied, or higher rates
of fertilizer will need to be applied. In any
case the the benefits to renewal must be adjus-
ted by the costs these changes in management
will Impose.

In spite of the large amount we do not know
about how the fungus affects feed consumption
and performance by animals, cow-calf operators
need to make informed choices about pasture re-
newal on what little evidence does exist. What
follows is based on ad hoc guesses on the effect
of fescue fungus on animal performance and con-
sumption.

Effects of Fescue Fungus Renewal on Animal Per-
formance :

Rule 1) Fbr every 10 percent decline in in-
festation level, calf daily gains (ADG) increase
by .1 Ib/hd/day for the spring and suirmer gra-
zing season.

Rule 2) For every 10 percent addition of clo-
ver to a grass sod, calf ADG increases by .1
Ib/hd/day over the same season. The maximum
clover in a clover-grass mix is 30 percent.

Effects Fescue Fungus Renewal on Animal Consump-
tion:

Rule 3) Animals consuming fescue infested
with fungus experience poor performance because
they consume less.

Rule 4) For every .1 Ib/hd/day increase in
calf ADG, stocking rate (cow-calf units /acre)
declines by 3 percent.

There have been numerous articles which contain
calculations purporting to show the effect of
Rule 1) on net returns to cow-calf production.

A typical example is as follows: Renewing a
pasture with 60 percent infestation to one with
no infestation will lead to 120 more pounds of
calf sold per acre if one cow-calf unit grazes
one acre for 200 days. This additional output
may be valued at current beef prices, say
$.60/lb, to yield an additional $72 in net in-
come per acre.

The problems with these calculations are two-
fold. First, such calculations completely
Ignore the effect renewal will have on consump-
tion of grass and hence soil nutrients. Net

41

Income per acre must be adjusted downward by the
value of the additional soil nutrients it takes
to get an additional 120 pounds per acre. Se-
cond, the renewed pasture will produce a much
heavier calf than will the unrenev;ed pasture.

The heavier calf will cotmiand a lower per pound
price than will the lighter calf. The $.60 price
used above needs to be adjusted by the weight
discount experienced by the heavier calf.

In order to overcome these shortccmings in calcu-
lating benefits to fescue pasture renewal, the
above rules were Incorporated in model of a cow-
calf enterprise grazing fescue over a 216 day
season. Per acre gross revenues and "fungus
savings" were calculated for two reestablishment
options, one with clover and one without, and a
renovation option, for alternative levels of ini-
tial fungus infestation. "Fungus savings" are
essentially increases in net return per acre due
to renewal. Given Initial Investment costs for
each renewal option, a rate of return was calcu-
lated at each infestation level. For those
treatments with clover (assumed to live three
years), yearly credits for nitrogen savings and
triennial debits for clover renovation were added
to the cash flow generated by fungus savings.
Table 1 gives yearly and triennial maintenance
cost comparisons for a clover-fescue stand versus
straight fescue stand.

The basic model is that given in the NRG,

Nutrient Requirements for Beef Cattle. Addl
tional assumptions are:

1. The dry matter available for consumption per
acre per grazing season is constant across all
Infestation levels and forage species.

2. Total consumption per acre per grazing sea-
son by the herd is consteint across all infesta-
tion levels and forage species.

These obviously false assumptions imply that it
is possible to infinitely vary stocking rate.

The purpose behind their use is to attanpt to
control for differences in management between a
situation in which an Infested acre is fully
stocked (l.e. all available dry matter is con-
sumed) and one in which a fungus free acre is
fully stocked. The bias against renewal these
assumptions may engender is readily admitted.

While feed demand can be fairly easily character-
ized , pasture feed supply available to satisfy
such demand cannot. Here we make the Initial
assumption that there are 5000 pounds of dry
matter (at NRG values for NQn and NEg) available
for consumption and that all of it is consumed.
This value is varied in the sensitivity analysis
below. The supply of forage available under dif-
ferent fungus infestation levels and forage spe-
cie types has always offered a great problem in
measurement. Without more research to tell us
how availability will vary in these situations,
we let the above assumption suffice.

RESULTS

Table 2 gives gross revenue per acre, stocking

rates, calf sale weights, prices, fungus savings
and rate return for three renewal options given
an initial infestation level. Various assump-
tions concerning calf beginning weights, calving
percentage, grazing season length, etc. are
given in the footnotes to that table. See
Standaert, 1986 for a more detailed version of
model input assumptions.

In Table 2, note that gross income generated by
each acre is similar regardless of Infestation
level. This is because as infestation levels
decrease. Increases in calf sale weight per cow
are offset by reductions in the number of cow-
calf units each acre will carry, as well as re-
ductions in the value of each pound of calf
produced. As Infestation levels decrease the
proportion of gross revenues generated by the
offspring of the cow increases while the propor-
tion generated by the cow decreases. Now each
cow-calf unit an acre is not required to carry
represents a savings in per head costs (vet &
med, labor & mgmt. Interest and other). There-
fore, net returns per acre Increase as fungus
infestation levels decrease.

Table 2 presents these Increases in net returns,
labelled there as fungus savings, for each re-
newal option. In the body of the table these
savings are given as the upper number under each
option. The lower number is an internal rate of
return computation. The internal rate of return
is computed assuming an initial Investment in
year 1 ( as given in the first line of Table 2),
and a stream of cash inflows and outflows in 21
subsequent years of grass stand life. For the
grass reestablishment treatment, only fungus
savings make up subsequent year cash inflows.

For the two clover treatments, maintenance and
triennial cost differences are added to fungus
savings in each year.

Negative infestation levels correspond to addi-
tion of clover to low fungus or zero fungus
pastures.

The rate of return in Table 2 is a real rate.
That is, all cash flows are after inflation has
been accounted for. A minimum real rate of re-
turn would probably be in the 3 to 4 percent
range for investments of the length of term we
are considering here. If we use 3 percent as a
minimum. Table 2 shows that renovation of a pure
grass stand by seeding clover into it will al-
ways meet that criterion regardless of infesta-
tion level. This does not mean that this option
will always dominate the other two options.

Table 2 shows that if sample infestation levels
exceed 40 percent, total reestablishment with a
clover grass stand will dominate. It also shows
that reestablishment with a clean straight fes-
cue stand will never dominate, but will come
close to the clover-grass reestablishment option
at high rates of infestation.

Of course, if required minimum real rates of
return are higher, investing elsewhere may be
wiser than pasture renewal if infestation levels
are low.

42

Table 1. Maintenance year costs for fescue and fescue clover pastures

Fescue

Fescue/Clover

Category Units

Price

Quantity

$/ac

Category

Units

Price

Quantity

$/ac

Operating Inputs

0-10-20, bulk cwt.

7-35

4.00

$29.40

0-10-20, bulk

cwt.

7.35

5.00

$36.75

30% Nitrogen cwt .

6.25

5.00

31.25

Tractor fuel & lube

4.00

Tractor fuel & lube

2.00

Tractor repair

1.50

Tractor repair

.75

Machinery repair

.90

Machinery repair

.45

Total yearly operating cost

67.05

Total yearly operating cost

39.95

Lime, applied every

Lime applied every

three years ton

31.00

1.00

31.00

three years

ton

31.00

2.00

62.00

Renovation every

three years

(exclusive of lime)

71.94

Total triennial maintenance cost

98.05

Total triennial

maintenance cost

133.94

Table 2. Savings from fescue pasture renewal, by fungus infestation level. Also stocking rates and
internal rates of return over 21 year life of stand.

Fungus Savings

Internal Rate of Return

Infestation

Level (a)

Ending

Grazing

Weights(c)

Price

Stocking

Rate (Cow-
Calf Units)

Gross
Returns
per Acre

Reestablishment

Clover/grass(d) Grass

Renovate

Clover/grass

%

lbs

$/cwt

CC/acre

$/acre

$/ac

$/ac

$/ac

%

%

Initial Investment

$175

$140

$143

Maintenance Year Expenses

$40

$67

$40

Triennial Year Expenses

$134

$98

$134

steer

654

63

heifer

590

55

-30 cow

1000

35

.80

257

—

—

—

repl(b)

910

53

steer

632

63

heifer

567

55

-20 cow

1000

35

.83

259

—

—

—

repl.

889

53

steer

610

63

heifer

547

55

-10 cow

1000

35

.86

260

—

—

—

repl.

867

53

steer

589

65

heifer

526

55

0 cow

1000

35

.88

266

1.64

—

1.64

repl.

824

53

1.1

3.2

steer

567

65

heifer

504

55

10 cow

1000

35

.91

267

4.21

2.57

2.52

repl.

824

53

3.6

4.2

43

Table

2. Savings from fescue pasture

renewal (continued).

steer

546

65

heifer

482

56

20

cow

1000

35

.94

268

6.37

4.74

3.20

repl.

802

53

5.5

-3.5

6.0

steer

524

65

heifer

461

56

30

cow

1000

35

.97

269

9.64

8.01

8.01

repl.

781

53

8.2

1.3

9.9

steer

502

65

heifer

439

56

40

cow

1000

35

1.00

269

13.10

11.66

9.09

repl.

759

53

11.0

5.4

10.9

steer

481

67

heifer

418

56

50

cow

1000

35

1.04

273

13.26

11.63

6.89

repl.

738

53

11.0

5.4

steer

459

67

heifer

396

57

60

cow

1000

35

1.07

273

17.11

15.48

7.47

repl.

716

53

13.9

9.1

9.3

steer

438

67

heifer

374

57

70

cow

1000

35

1.11

273

22.14

20.50

8.84

repl.

694

54

17.4

13.5

10.7

steer

416

67

heifer

331

57

80

cow

1000

35

1.14

271

27.65

26.01

14.39

repl.

673

54

21.1

17.9

15.7

steer

394

69

heifer

331

57

90

cow

1000

35

1.18

274

29.88

28.24

12.77

repl.

651

54

22.5

19.6

14.3

steer

373

69

heifer

310

57

100

cow

1000

35

1.22

272

36.56

34.92

14.42

repl.

630

54

26.9

24.6

15.7

(a) Negative infestation levels represent the addition of clover to a fescue pasture.

(b) The culling rate for replacanient heifers is 50 percent higher than for cows. All cows not producing
calf for sale are sold.

(c) For this example, calving percent is 82, per cow costs are $123. Calves are bom Decanber- January and
sold in November. Grazing season is 216 days; available dry matter per acre is 5000 pounds. Clover
stand life is three years; fescue stand life (infested or not) is 21 years. IRR is computed over a 21
year period. Initial weights and rates of gain at zero infestation are: Steers(200,1.6) , Heifers(l80,
l.A), Cows (1000, 0), Replacement heifers (500, 1.4) in pounds and pounds per day.

(d) Fungus savings for clover/grass assume a 30 percent clover-70 percent grass mixture. Fungus savings
listed do not account for difference in maintenance and triennial year costs. However, IP® does.

4A

Table 3. Sensitivity Analysis: effects of changes in model assumptions on domination range of fescue

pasture renewal options.

Reestablishment

Variable changed Clover/Grass Grass

Renovation

Clover/Grass

Invest Elsewhere
(Return 3 %)

Domination Range, Percent

Baseline solution

AO

- 100

—

0-40

—

Pasture Variables

Clover, 2 yr. life

40

- 70

70 - 100

30 - 40

0-30

Grass life, 15 years

60

- 100

—

0-60

—

Available dry matter (5000+10*1)

—

—

80 - 100

0-80

Animal Performance Variables

Calving percent, -10 %

—

—

30 - 100

0-30

Calving %, ( .82-.0005*!)

30

- 100

—

0-30

—

Gain rule, -20 %

40

- 100

—

20 - 40

0-20

Cow gain, (-.005*1)

60

- 100

—

30 - 60

0-30

Financial Variables

Price discount for weight = 0

20

- 100

—

0-20

—

Price discount for weight, db Id.

60

- 100

—

30 - 60

0-30

Zero fixed costs

—

—

80 - 100

0-80

Maint. cost difference, -20%

40

- 100

—

30 - 40

0-30

Triennial cost dlff . , +20%

40

- 100

—

20 - 40

0-20

M & T cost difference = 0

—

40 - 100

—

0-40

SENSITIVITY ANALYSIS

In this section, some of the model variables
whose values are least known will be varied to
test the sensitivity of rates of return.

Table 3 gives the results of this analysis. In
addition to the three renewal options a fourth
option is included. This is to invest elsewhere
and earn a return of at least 3 percent in real
(inflation adjusted) terms. The numbers in Table
3 give the range in which a particular option
dominates all other options when the Indicated
variable is altered. Only one variable is al-
tered at a time. The first line of the table
gives the baseline solution.

Pasture Variables

Clover life. Because of weather, slope, acidity
levels, etc., clover may not last the three years
assumed in the baseline solution. Assuming a two
year clover life substantially changes cash flows
associated with clover maintenance and renova-

tion. In the baseline solution, renewal with a
three-year clover crop paid for triennial reno-
vation costs with three years of nitrogen sa-
vings. With a two-year clover crop, renovation
costs are Incurred more frequently and only two
years of nitrogen savings are available to pay
for renovation. With a two-year clover crop it
would take infestation levels of at least 30
percent before renewal becomes preferable to
investments in other projects earning at least 3
percent. At levels of infestation greater than
70 percent, the straight grass reestablishment
option is the most preferable.

Grass Life. On the other hand suppose that fun-
gus free grass does not have the longevity of
infested grass. Suppose fescue with any posi-
tive level of infestation lasts 21 years as in
the baseline solution, but that zero infested
fescue has a life of only 15 years. This does
not affect the rate of return to the renovation
option but does affect the rate of return to
each reestablishment option. As a result the
renovation option is dominant up to the 60 per-
cent infestation level.

A5

Available Dry Matter. Allowing dry matter avail-
ability to Increase as I level increases causes
stocking rates to dramatically Increase. Gross
revenue per acre rises faster than do per cow
costs as I level Increases. Renovation is the
dominant option for I levels above 80 percent.
Investing elsewhere doninates for lower levels.

Animal Performance Variables

Calving Percent. A reduction in calving percent
raises feed requiranents per cow-calf unit be-
cause of the extra replacement heifers the unit
must carry. Lower calving percent thus means
lower stocking rates at each level of infesta-
tion. As infestation levels increase, the pounds
of calf sold per acre are nearly constant, but
the pounds of cow and replaconent heifer sold per
acre Increase. Thus gross revenue per acre in-
creases with higher I levels and Incease at a
rate similar to increases in per cow costs. The
result is that renovation is the only renewal
option which dominates, but does so only for in-
festation levels above 30 percent.

\i/hen calving percent is allowed to vary negative-
ly with infestation level, the dominating options
are very close to those in the baseline solution.

Gain Rule. The gain rule was decreased by 20
percent so that each 10 percent Improvement in
fungus infestation level was asociated with a .08
pound per day difference in calf gain. This of
course reduces some of the benefits to pasture
renewal. The result is that the "Invest else-
where" option dominates for I levels below 20
percent, the renovation option for levels between
20 and 40 percent and the clover-grass reesta-
blishment option dominates for levels above 40
percent.

Financial Variables

Price Discounts. Allowing no price discounts for
heavier weighted calves Increases the range over
which the clover-grass reestablishment option
dominates. Similarly doubling the discount for
added weight causes the Invest elsewhere option
to dominate for I levels up to 30 percent. The
renovation option dominates for I levels between
30 and 60 percent and the clover-grass reesta-
bllslment option dominates for all higher levels.

Zero Fixed Costs. Fixed costs are Interest and
depreciation on value tied up in every cow-calf
unit. If these costs are set at zero, most of
the per cow cost savings associated with lower
stocking rates are erased. It makes little sense
to engage in any renewal option under these con-
ditions unless infestation levels are very high.

Maintenance Cost Difference. Reducing the cost
difference between maintaining fescue-clover and
straight fescue by twenty percent shifts much of
the advantage that renovation enjoyed in the
baseline solution to the invest elsewhere op-
tion. This reflects the fact that at low levels
of infestation renovation is the dominant option
not because of fungus savings but rather because

of savings in maintenance costs.

Triennial Cost Difference, i^lhwn both mainten-
ance and triennial cost differences are set
equal to zero, three-year clover in any renewal
option loses its dominance at all levels of
infestation. The reestablishment of straight
fescue dominates for I levels above 40 percent.

FUTURE RESEARCH

Research needs concerning the effects of fescue
fungus on animal performance and consumption are
many. First, we must try and learn how it is
that the Ingestion of the fungus affects the
animal. Is it a toxic effect which reduces the
rate at which the animal is able to convert feed
into product or is it an appetite depressant?

How does the fungus affect ability to rebreed,
fetal growth and abortion incidence? Do dif-
ferent breeds of animal respond differently to
the prescence of the fungus in fescue material?

Second, how long will fungus-free fescue live
under different management regimes; will ferti-
lizer response be the same for fungus-free grass
as it is for infested grass; what is the longe-
veity of the plant if attacked by insects; and
finally what is gain response difference under
pasture neglect?

Third, how should management practices be al-
tered in a fungus-free situation; should ferti-
lizer amounts be Increased; what stocking rates
should be recommended?

Finally it appears that farmers are slow to a-
dopt the new fungus free varieties. Vfliy? A
large part of the savings to be gained from
replacement of the older varieties is the reduc-
tion in per head costs each renewed acre en-
joys. Beef cattle producers are notoriously
slow in responding to changes in these costs.
VIhat educational effort needs to be brought to
bear in order to speed up the process of adop-
tion of the newer more productive varieties?

Literature Cited

Green, J., J. P. Mueller, W. M. Lewis, J. E.
Standaert. "Tall Fescue Endophyte: Forage
Crop Newsletter, Memo No. 16, Feb. 1985. N. C.
Agricultural Extension Service. NCSU.

Jacobs, V. E. "The Subtle Economics of Improv-
ing Pasture Quality in Summer Grazing
FTograms." Farm Management Newsletter, May 28,
1983 Missouri Cooperative Extension Service.

National Research Council. Nutrient Requirements
for Beef Cattle. 6th revised edition, 1984.

Standaert, J. E. "The Cost and Benefits of

Fescue Pasture Renewal." Economic Information
Report, Department of Economics and Business,
NCSU Forthcoming.

46

PROGRESS OF S-167 REGIONAL PROJECT

C. P. Bagley^

The S-167 Regional Project entitled "Utilization
of Forages for Production of Slaughter Cattle
Throughout the Year" was initiated in 1981 and
scheduled for termination in September, 1986.

The project has as its objectives to 1) develop
and evaluate forage and cattle management
systems to enhance efficiency of resource
utilization for uniform distribution of
slaughter cattle production throughout the year,
and 2) estimate the economic feasibility of
year-round production of slaughter cattle under
different physiographic conditions.

Under the main objectives were five study areas
which included a) calf production, b) growing-
finishing production systems, c) legume-grasses,

d) forage production and utilization, and

e) economic analysis of production systems.

State experiment stations which were cooperators
in this study included Arkansas, Georgia,
Kentucky, Louisiana, Mississippi, North
Carolina, Puerto Rico, South Carolina, Texas
and Virginia, along with the USDA-ARS location
in Oklahoma. The participants have met on an
annual basis to discuss research results and
discuss further directions. The S-167 group
has maintained close contact with the S-156
(Southern Region Project "Simulation of Forage
and Beef Production in the Southern Region")
group and have had joint annual meetings on

two occasions.

One of the more important aspects of the S-167
group has been its recommendations on data
collection procedures for forage-beef grazing
studies. The list of data to be taken was
derived from scientists' input from several
disciplines. While the committee responsible
for the recommended procedures does recognize
that these can not be followed in all studies,
these procedures will yield more in-depth
details which would be useful in adapting
these studies to the modeling efforts currently
underway.

A large volume of data has been published in
numerous publications. This regional project
has provided for enhanced communication
between scientists between states and has led
to a more concentrated effort in several
research areas. Presently, a final report on
the project is being developed with the project
to be terminated September, 1986. Currently,
a regional project is being proposed which
will not be a continuation of S-167, but it
will use data and knowledge generated from both
S-156 and S-167 to glean the strongest points
of both studies along with some more recently
recognized high-priority research areas.

Rosepine Research Station, La . Agr . Exp.
Sta., LSU Agricultural Center, P. 0. Box 26,
Rosepine LA 70659

47

YIELD AND QUALITY DIFFERENCES AMONG CULTIVARS
OF ENDOPHYTE-FREE TALL FESCUE

Joe Bouton^

Of the many tall fescue (Festuca arundinacea
Schreb.) cultivars available, the following are
reported by forage extension specialists to be
currently used or recommended in the Southeast-
ern United States (J. H. Bouton, unpublished
survey): Forager, Johnstone, Kenhy, Kentucky

31, Missouri 96, and AU Triumph. However, when
year of release of each cultivar is examined
(Buckner, et al., 1985; Balauch, et al., 1980),
then it is noticed that Kentucky 31 was released
in 1943 and the other cultivars were released
between 1977 and 1982. Why is there a 34 year
gap between Kentucky 31 and the others? I
think the answer lies simply with the endophyte
fungus (Acremonium coenophialum Morgan-Jones
and Gams) which infects tall fescue. By not
knowing the level of fungal infestation (or
even for that matter that the fungus even
existed), testing cultivars against Kentucky 31
during this 34 year period would and did give
contradictory results. It wasn't until recently
when endophyte-free versions of cultivars were
available could agronomic or animal performance
differences be assessed.

Differences in total seasonal yield are a very
traditional means of assessing cultivar perform-
ance. The data presented in table 1 show
results from recent cultivar trials. Three
important points can be made from these data.
First, there is a great deal of variation from
state for state for cultivar performance. This
indicates each cultivar' s adaptation and per-
formance needs to be assessed before recommenda-
tion. Each state should not rely too strongly
on results from neighboring states. Second,
total yield can be misleading if one needs a
certain seasonal distribution of the yield. An
example is the cultivar AU Triumph whose super-
iority in autumn and winter production was
shown at all the testing locations in table 1.
Production during this period would have great
potential for certain grazing systems. Third,
there was no indication from any of the trials
about the fungal endophyte level for each
cultivar. This could be important if future
experiments prove endophyte infestation leads
to more (or less) yield and persistence. To
avoid this problem, future yield trials should
be conducted with fungus free swards of each
cultivar since that is how the farmer will use
them.

Of utmost importance to many would be the
differences among tall fescue cultivars in
terms of animal performance. Because the
fungus problem has so recently been demonstrat-
ed, there are few data on cultivar differences
for animal gains. The data summarized in table
2 show the new cultivars Johnstone and AU

Triumph to give superior animal performance
when tested against Kentucky 31 comparably
infected with a low level of fungus. Therefore,
it appears from these limited data that at
least when grown in their areas of adaptation,
the newer cultivars give better animal perform-
ance when compared to the old standard Kentucky
31.

In summary, the fungus problem greatly limited
past assessment of animal performance differ-
ences among tall fescue cultivars. Recent data
on the newly released cultivars have shown
their superiority to Kentucky 31 when tested in
fungus-free swards. However, future assessments
of new cultivars against standards such as
Kentucky 31, will need to be conducted at low
fungus infestation levels and determined on a
state by state basis before true differences
can be demonstrated among cultivars.

Table 1. Relative annual yield of tall fescue
cultivars at different locations in the South-
eastern United States.

, , North „

Cultivar Alabama Georgiaf Carolina^ Tennessee
(0^)

Kentucky

31

100

100

100

100

Forager

—

96

109

94

Kenhy

Missouri

89

100

94

97

96

80

104

83

103

AU Triumph

111

113

97

100

■From Pedersen, et al. , 1982.
iFrom Wilkinson, et al., 1984.

^From Daniel, et al., 1983 and Daniel, et al.

^1985.

From Reynolds, 1984.

Table 2. Relative animal performance in terms^
of average daily gain (ADG) and total gain ha
of 3 tall fescue cultivars containing low fungal
endophyte levels when tested in three states.

t 1 ^

Alabama Georgia! Kentucky

Cultivar ADG Gain ha ^ ADG Gain ha ^ ADG
-■■■ — ^0

Kentucky

31 100 100 100 100 100

Johnstone 121 110 127

AU Triumph 123 117 127 149

t

1

§

Grazing period Oct. - Dec., 1980-83; f
Pedersen, et al., 1986.

Grazing period April - Nov., 1984-85;
John Stuedemann, unpublished data.
Grazing period 112 days, Spring-Summer
from Buckner, et al., 1985.

rom
from
, 1983;

-^Agronomy Department, University of Georgia,
Athens, GA 30602.

48

Literature Cited

Balauch, S. J. , S. C. Stratton, and R. J.

Buker. 1980. Registration of Forager
tall fescue. Crop Sci. 20:670.

Buckner, R. C. 1985. The fescues, p. 233-240.
In M. E. Heath, R. F. Barnes, and D. S.
Metcalfe (ed.) Forages - The science of
grassland agriculture (4th edition). Iowa
State University Press, Ames, lA.

Buckner, R. C., J. A. Boling, P. B. Burrus, Jr.,
L. P. Bush, R. W. Hemken, and M. R.

Siegel. 1985. Johnstone tall fescue.

Univ. Kentucky Coll. Agric. Spec. Rpt.

1-85.

Daniel, D. W. , J. P. Mueller, and J. T. Green.
1983. Forage crops testing 1982. North
Carolina Agric. Ext. Ser. Crop Sci. Rept.
No. 91.

Daniel, D. W. , J. P. Mueller, and J. T. Green.
1985. Forage crops testing 1984. North
Carolina Agric. Ext. Ser. Crop Sci. Rept.
No. 99.

Pedersen, J. F., C. S. Hoveland, and R. L.
Haaland. 1982. Performance of tall
fescue varieties in Alabama. Alabama
Agric. Exp. Stn. Circ. 262.

Pedersen, J. F., J. A. McGuire, S. P. Schmidt,
C. C. King, Jr., C. S. Hoveland, and
L. A. Smith. 1986. New Zealand J. Exp.
Agric. (In Press).

Reynolds, J. H. 1984. Yield of tall fescue
varieties. Univ. Tennessee Res. Rept.
84-04.

Wilkinson, S. R. , J. H. Bouton, D. P. Belesky,
J. W. Dobson, Jr., and R. N. Dawson.

1984. Yield of tall fescue cultivars and
experimental lines in North Georgia.

Univ. Georgia Agric. Exp. Stn. Res.

Bull. 319.

49

EXPLORING THE PLANT-ANIMAL INTERFACE - DIET
SELECTION, CANOPY STRUCTURE AND INTAKE
MEASUREMENT PROBLEMS AND SOLUTIONS

J. R. Forwood ^

In attempting to develop improved systems of
producing beef or milk, it is not enough to show
a difference between two systems or treatments.
Our goal is to discover the "whys" and as com-
pletely as possible to understand and explain
the forage-livestock responses.

Defining how livestock select species or plant
parts in the pasture should aid in understanding
why they perform the way they do. To date,
esophageal fistulation is accepted as the most
accurate method of assessing animal selection
but is not utilized by many scientists because
of the labor and cost of maintaining research
animals. Another major concern is poor animal
health and death loss due to the combined surgi-
cal and cannulation procedures. Many cannulas
with metal sleeves cause esophageal "depression"
or "pocketing" with pressure on the interior of
the esophagus by the edges and ends of the
cannula sleeves. The pressure causes irrita-
tion, pressure necrosis, restricted blood
supply, mucosal surface erosion and accumulation
of granulated and fibrous tissue which results
in loss of peristaltic action and eventual star-
vation. Advances have been made with light-
weight materials such as polyethylene (Denny,
1981) and flexible silicone (Ellis et al.,

1984). We have developed a one-piece cannula
(modified ileal plastisol cannula-MPl) that
combines the positive attributes of many exist-
ing cannulas (Forwood et al., 1985) (Figure 1).

/40mm

I

Fig. 1. A one-piece modified plastisol
reentrant illeal cannula for use in esophageally
fistulated cattle.

Its greatest advantages are (1) reduced esopha-
geal irritation and associated health problems;
(2) elimination of accidental swallowing; (3)
simple construction; 4) rapid insertion; and (5)

^ USDA-ARS, Research Agronomist and Assistant
Professor, U. of MO, Columbia, MO 65211

greatly reduced cost. The cost of these can-
nulas is less than $1.00 compared to $35-75.00
for other cannula types. Our studies at
Columbia and experience at other institutions
has also shown health advantages in coating
sleeve-type cannulas with plastisol (Forwood et
al., 1985). Hopefully, until an improved method
of estimating diet selection is found, these and
other advances in the use of fistulated animals
will make the technique more palatable to
researchers, thereby advancing understanding in
this area of research.

It is widely accepted that animal performance on
pasture can be improved by overseeding legumes
into the sward (Smith et al., 1975; Strieker et
al., 1979). Through diet selection of esopha-
geally fistulated animals, we hoped to define
cattle preference between red clover (RC),
birdsfoot trefoil (BFT), and alfalfa all mixed
with orchardgrass at different times of the
grazing season, to determine the quantity
selected and to relate the above to steer
performance. Although data analysis is not com-
plete, it appears the animals prefer BFT (10.9%)
over RC (6.24%) in the spring and fall and
perform at a higher level on BFT. Selection of
legumes by steers was roughly 5 to 7 percentage
points above that available in the pasture (1.67
and 3.95% available red clover and birdsfoot
trefoil, respectively). On occasion when steers
were turned into ungrazed pasture having signif-
icantly greater legume content than previous
pasture, selected legume percentage remained at
approximately the same level. Pasture and diet
quality data and other comparisons are not com-
plete, but data such as this may aid in recom-
mending the species preferred by livestock, the
one on which they perform best and at what time
they prefer it.

Aside from obvious problems in collecting field
data with fistulated animals, microhistological
analyses of masticated samples is laborious and
costly even in a tame pasture situation involv-
ing a small number of species. In our situation
where essentially one grass and one legume were
involved per treatment, we were concerned only
with identifying grass and legume percentages
consumed. We investigated the use of pinitol
( l-D-3-O-methyl-chiro-inositol) concentration in
determining legume concentration of esophageal
samples as suggested by Smith (1982) in order to
overcome the labor, training and cost of micro-
histological identification.

Found only in legumes and not subject to large
plant part and maturity variation. Smith pro-
posed that determination of pinitol concentra-
tion in esophageally collected samples of grass-
legume mixtures might estimate legume concentra-
tion. Results comparing two microhistological
methods with pinitol concentration showed the
microhistological methods in agreement but that
pinitol underestimated the legume component
(Table 1). We speculate mastication and saliva-
tion are leeching pinitol from the samples and
at this point suggest it not be used as a labor
and cost saving method in determining legume

50

selection by esophageally fistulated animals
(Forwood et al. , in review).

Table 1. Average Pasture and Hay Phase Legume
Percentages as Estimated by Methods of Sparks
and Malechek (SM), Heady and Torrell (HT) and
Pinitol Concentration

Pasture Phase

SM

HT

P

Orchardgrass + RC

5.5

7.4

1.5

Orchardgrass + BFT

8.0

10.7

3.6

Hay Phase

Orchardgrass + RC

7.0

7.3

1.9

Orchardgrass + Alf

7.1

7.1

1.1

Whether discussing ruminants or monogastrics,
quantity of food eaten is the major factor
affecting animal productivity. Feed intake by
grazers is related to time spent eating, the
number of bites per unit of time and the average
bite size (Spedding et al., 1976). Attention
has been focused on quantity and quality of feed
available; however, we may learn considerably
about pasture and animal management by studying
how sward canopy structure affects animal per-
formance and how animals defoliate the canopy.

Our studies concern (initiated spring 1986)
comparison of season-long and complementary
grazing systems. We hope to explain performance
differences, if any, and gain management insight
by measuring leaf and stem ratios, quality and
quantity of each, defoliation sequence, intake,
bolus size and grazing time. Detailed studies
like this may yield valuable information to
plant breeders like Dr. D. A. Sleper at the
University of Missouri, who has developed low
and high leaf area tall fescue types for
advanced evaluation with grazers.

While it is important to understand how intake
is affected by canopy structure and vice versa,
one must realize that we still do not have a
direct, accurate and rapid method of measuring
intake of free roaming grazers. Thus far the
best available methods include estimates of
herbage loss from the pasture or animal gain,
fecal output and herbage digestibility equa-
tions, and indicator methods using chromic oxide
or rare earths. More direct methodology has
been attempted (Horn and Miller, 1979; Stuth et
al., 1981) but nothing has reached the pasture-
use stage.

A conductivity transducing cannula (CTC) has
been developed and tested which can be placed in
the esophagus of fistulated cattle (Forwood et
al., 1985). This device signals number of boll
swallowed which is positively related to dry
matter intake of orchardgrass hay (r^=0.81) and
chopped big bluestem grass (r^=0.99) (Table 2).
Although the original objective was to measure
the exact quantity swallowed (and it may still
be achievable), intake measurement by counting

Table 2. Dry Matter Intake (kg) and Number of
Bolus Swallows (determined by the CTC device) of
Orchardgrass Hay and Chopped Big Bluestem Fed to
Confined 1-year-old Esophageally Fistulated
Steers

Steer

identification

Intake

Number of
swallows

r2

Orchardgrass

Slmmental

A

1.22

78

Simmental

A

1.86

97

Simmental

A

1.94

105

0.81

Simmental

A

1.97

111

Angus B

2.05

110

Angus B

2.07

127

Big Bluestem

Angus B

0.68

44

Ang us B

0.73

46

0.99

Angus B

1.02

57

boli numbers is the current method. This method
assumes uniform bolus weights over various herb-
age species, herbage maturities and animal
sizes. Existing studies in confinement show
bolus weight to vary among studies, cows and
feeds (Schalk and Amadon, 1928; Bailey, 1961;
and Gill et al., 1966) while Stuth and Angell
(1982) found herbage allowance, cow size and
seasons of the year had no significant effect on
bolus weight under grazing conditions. Prelimi-
nary information under grazing in Missouri
(Forwood, unpubl.) indicates a positive rela-
tionship between bolus size and animal size and
an interaction between small steers and seasons
but none between large steers and seasons.
Further data are needed, but indications are
that if bolus counting is to accurately measure
intake, calibration for animal size and forage
type may be necessary.

Additional modifications of the CTC device are
currently underway. It appears a thermistor
will detect boli numbers just as accurately as
electrodes and may lend itself to a very minor
surgical installation as opposed to the more
radical fistulation procedure. Studies on pas-
ture are being planned for the 1986 grazing
season with either animal-carried digital read-
out data storage modules or telemetry devices
interfaced with the intake device.

The studies mentioned above and their obvious
difficulty "requires that the interface itself
be Identified as the focal point for investiga-
tion, rather than simply as the common boundary
between adjacent sectors of interest" (Hodgson,
1985). A great deal of basic and applied
research will have to be done not only in
exploration of the interface but in order to
develop the methodology and instrumentation
which will allow rapid and accurate exploration
of the area.

51

Literature Cited

Bailey, C. B. 1961. Saliva secretion and its
relation to feeding in cattle. Brit. J.
Nutr. 15:433-451.

Denny, G. D. 1981. A modification of an

esophageal fistula plug that allows low
maintenance of free-ranging sheep and
goats. J. Range Manage. 34:152-153.

Ellis, W. C., E. M. Bailey, and C. A. Taylor.

1984. A silicone esophageal cannula;
its surgical installation and use in re-
search with grazing cattle, sheep or
goats. J. Anim. Sci. 59: 204-209.

Forwood, J. R. , J. L. Ortbals, G. Zinn and

J. A. Paterson. 1985. Cannula adapta-
tions for esophageally fistulated cattle.

J. Range Manage. 38(5) :474-476.

Forwood, J. R. , M. M. Hulse, and J. L. Ortbals.

1985. Electronic detection of bolus
swallowing to measure forage intake of
grazing livestock. Agron. J. 77:969-972.

Gill, J., R. C. Campling, and D. R. Westgarth.
1966. A study of chewing during eating
in the cow. Brit. J. Nutr. 20:13-23.

Hodgson, J. 1985. The significance of sward
characteristics in the management of
temperature sown pastures. XV Interna-
tional Grassland Congress; Plenary
Session, Kyoto, Japan.

Schalk, A. F., and R. S. Amadon. 1928. Phy-
siology of the ruminant stomach (Bovine) :
Study of dynamic factors. N. Dak. Agric.
Exp. Stn. Bull. 216.

Smith, A. E. 1982. Determining the legume-
fraction of a grass-legume pasture by
pinitol analysis. Agron. J. 74:157-159.

Smith, H. , V. L. Lechtenberg, D. C. Petrltz,
and K. G. Hawkins. 1975. Performance
of cows grazing orchardgrass , fescue or
fescue-legume. J. Anim. Sci. 41:339
(Abstr . ) .

Spending, C. R. W. , R. V. Large, and D. D. Kydd .
1966. The evaluation of herbage samples
by grazing animals. Proc. 10th Interna-
tional Grassland Congress, Helsinki,
pp. 474-483.

Strieker, J. A., A. G. Matches, G. B. Thompson,
V. E. Jacobs, F. A. Martz, H. N. Wheaton,

H. D. Currence, and G. F. Krause. 1979.
Cow-calf production on tall f escue-ladino
clover pastures with and without nitrogen
fertilization or creep feeding spring
calves. J. Anim. Sci. 48:13-16.

Stuth, J. W. , K. J. Kanouse, J. F. Hunter

and H. A. Pearson. 1981. Multiple elec-
trode impedance plethysmography system for
monitoring grazing dynamics. Biomed. Sci.
Instr. 17:121-124.

Stuth, J. W. and R. F. Angell. 1982. Effect
of seasonal herbage allowance on bolus
weights of cattle. J. Range Manage.
35:163-165.

52

CANOPY STRUCTURE EFFECTS ON INGESTIVE BEHAVIOR

1 2
J. E. Moore , and L. E. Sollenberger

THE PLANT-ANIMAL INTERFACE

Interactions between forage plants and animals
during consumption of forages are being described
as the "plant-animal interface." The interactions
involve (1) effects of forage characteristics upon
intake, digestibility, efficiency of nutrient
utilization, and animal performance, and (2)
effects of defoliation by grazing animals upon
regrowth, persistence, and composition of pasture
or range swards. The quantity and character of
the forage on offer determines the amount and
composition of pasture consumed by the grazing
animal, and the very act of consumption influences
the quantity and character of the residual forage
(Minson, 1983; Moore, 1983; Forbes et al., 1985).

Plant Component

The plant component of the interface may vary in
terms of (1) quantity aspects, e.g., herbage mass
(kg ha“') or herbage allowance (kg animal"'), and
(2) quality aspects, that is, characteristics of
the plant which determine quality, e.g., chemical
composition, physical characteristics (plant
anatomy and morphology), and, in grazed pastures,
canopy structure. Measures of canopy structure
include canopy height and canopy profile, i.e.,
vertical distribution of herbage in terms of bulk
density, percentage leaf, percentage green, and
percentage of each species in mixed swards.

Animal Component

The animal component includes a large number of
factors, but among the most important are those
that limit forage dry matter (DM) intake. Three
mechanisms of intake limitation have been de-
scribed: (1) metabolic, (2) distention, and (3)
behavioral (Hodgson, 1985).

In the metabolic control mechanism,

DM Intake = (DE Intake)/(DE Concentration)

and DE intake has an upper limit such that
increases in DE concentration result in decreases
in DM intake. This mechanism may apply to very
high-quality forages (Waldo, 1986). In addition,
lack of nutrients such as protein or certain
minerals may depress intake through some metabolic
limitation.

In the distention control mechanism,

DM Intake = (Fill)/(Retention Time)

and fill has an upper limit such that decreases

^Animal Science Department
'^Agronomy Department

University of Florida, Gainesville, 32611

in retention time (or increases in rates of diges-
tion, degradation and passage) result in increases
in DM intake. This mechanism is presumed to
account for much of the variation among barn-fed
forages where increases in forage maturity are
associated with decreases in voluntary intake
(Waldo, 1986).

Under grazing, ingestive behavior of animals may
override either of the other two intake control
mechanisms. In the behavioral control mechanism
(Hodgson, 1982),

DM Intake = (Bites per day)*(Bite weight)

where: Bites per day = (Grazing time)* (Bite rate)
Grazing time = min per day
Bite rate = bites per minute

In many cases, bites per day has an upper limit
set by either grazing time or bite rate. Compen-
satory increases in grazing time and bite rate may
occur when bite weight declines, but bite weight
has a major effect upon DM intake. Rate of total
grazing jaw movements varies little, and varia-
tions in bite rate occur due to variations in the
proportion of jaw movements which are bites
(Penning et al., 1984). Black and Kenney (1984)
reported that "prehending" bites ranged from 20 to
80? of total jaw movements in sheep. Chambers et
al. (1981) observed ratios of 1.1 to 1.7 jaw
movements per bite with sheep and cattle, which
are comparable to 47 to 37 bites per 100 jaw
movements. If there is variation in bites per 100
jaw movements, estimates of bites per minute and
bite weight based only on records of total jaw
movements may not be accurate.

No doubt there are shifts from one intake control
mechanism to another in grazed pastures due to the
effects of the animal upon the plant. As higher-
quality forage is removed, distention may replace
metabolic factors as an intake limit. When bite
weight is not limiting, then intake may be deter-
mined by the chemical and physical characteristics
of the ingested forages (Chacon et al., 1978). If
the rate of herbage consumption exceeds the rate
of regrowth, a lack of available forage may make
it impossible for the animal to consume enough to
meet the limit set by distention. When bite
weight is limited by lack of available or acces-
sible forage, then intake and animal performance
may be depressed (Ludlow et al., 1982).

CANOPY STRUCTURE, INGESTIVE BEHAVIOR, AND DIET
COMPOSITION

In some cases the structure of the canopy may
override distention or metabolic limits, and
intake is depressed due to behavioral limitation
(Ludlow et al., 1982). Although it may be
misleading to generalize about the relationships
between canopy structure and ingestive behavior,
Hodgson (1985) suggested that for temperate
pastures, bite weight is positively related to
herbage mass, canopy height, and bulk density.
There may be negative relationships, however,
among those same measures of canopy structure.

53

Tropical grass pastures are characterized by low
canopy densities and low leaf area densities
(Ludlow et al., 1982). The low leaf area density
tends to result in decreased bite weight and
decreased intake. Animal performance on such
pastures is not easily predicted from canopy
characteristics, but important considerations are
those that influence bite weight and nutritive
value of the diet selected (Chacon et al., 1978).
There may be a negative relation between bite
weight and nutritive value, however, suggesting
that selection and intake may be influenced by
different characteristics of the canopy.

Legume-Grass Pastures

Although there has been little work on grazing
behavior and diet quality of tropical legume-grass
pastures, it may be presumed that the presence of
legume in grazed horizons would Increase animal
performance (Reed, 1981) by increasing intake,
perhaps by increasing bite weight, or by increas-
ing nutritive value of the diet selected. Animals
on pasture graze selectively and generally consume
forage of higher nutritive value (protein and
digestibility) than that of the total forage on
offer (Arnold, 1980). In some cases, sheep
grazing a white clover-ryegrass sward selected a
diet higher in clover than was in either the total
canopy or the portion of the canopy being grazed
(Milne et al., 1982). On red clover-ryegrass
pastures, sheep selected clover leaf especially
when the canopy was grazed down quickly (Laidlaw,
1983). In a tropical savanna, cattle selected
legumes to a greater extent during the dry season
when green grass leaves were unavailable, than
they did during the rainy season (Bohnert et al.,
1985).

The effect of legume must be tested for specific
associations because it has not been demonstrated
that animals express nutritional wisdom when given
a choice of dietary components (Arnold, 1980), and
unpalatable constituents in certain legumes may
cause animals to select grass rather than legumes
(Marten, 1981). Examination of canopy profiles
and botanical composition of herbage consumed by
grazing animals will provide very useful informa-
tion for interpretation of the plant-animal
interface.

Florida Research

We conducted a grazing study to determine the
effects of variations in canopy characteristics of
Hgmarthria altissima ( limoograss ) -Aeschvnomene
americana- (jointvetch) pastures upon ingestive
behavior and diet botanical composition of
esophageal-fistulated steers (Moore et al., 1985),
and upon the botanical composition of herbage
consumed during an entire grazing period. The
study was superimposed upon a larger management
study (Sollenberger et al., 1985) in which 0.05-ha
pastures were grazed rotationally with five weeks
rest and two days grazing.

Two pastures varying in herbage mass and canopy
structure were selected on each of 12 weeks,
giving a total of 24 observations. Prior to

grazing, canopy structure was characterized by
clipping five, 0.5 m^ sites per pasture in 10-cm
layers, and separating herbage into legume, grass,
and weed components. Calculations were made of
botanical composition of whole canopy and two
canopy fractions: upper layer, which was the top
20 cm (or 10 cm in short pastures but never the
bottom 10 cm), and grazed horizon, which was the
herbage above 10 cm for pastures less than 60 cm
tall but that above 30 cm for pastures from 80 to
100 cm tall.

Ingestive behavior was measured with four esopha-
geal-fistulated steers during 20-min collections
after the animals were first placed on pastures at
the start of grazing periods. Extrusa were col-
lected in screen-bottom bags. Total jaw movements
were measured electronically, and actual bites
(forage being severed) were recorded by hand when
a jaw movement was associated with the sound of
forage being severed. Additional steers were
added for the remainder of the grazing period.

Following grazing, samples of residual forage were
separated into legume, grass, and weeds. The
percentage legume in consumed herbage was calcu-
lated as follows:

(Pregraze-Postgraze Legume Herbage Mass) • 100

(Pregraze-Postgraze Total Herbage Mass)

Canopy Character

Bulk density of the legume was fairly constant
throughout the canopy but density of grass
increased from top to bottom of the canopy. In
the whole canopy, percentage legume was always
less (0.7 to 38.3) than that of grass (46.4 to
93-5). Legume as a percentage of the total of
legume plus grass averaged 19.6, but ranged from
1.0 to 44.8. Legume percentages in upper layer
and grazed horizon were correlated with that in
whole canopy, but that in the upper layer was
about twice that in the canopy as a whole.

Ingestive Behavior

Total grazing jaw movements varied from 50.1 to

76.8 per minute and there were no differences
among pastures or animals. For 19 of the 24
pastures, means were between 62 and 72 per minute,
which are similar to, or slightly higher than,
values reported by Chacon and Stobbs (1976) for
"rate of biting." The number of bites per minute
(forage being severed) varied from 19.7 to 37.5.
The correlation between bites per minute and total
jaw movements per minute was low (r=.29, n=76,
P<.05). Bites per 100 jaw movements varied from

27.9 to 59.0 with lower values indicating a
greater proportion of total jaw movements associ-
ated with either mastication or manipulation of
forage prior to biting and (or) swallowing. Our
observations in the field support the conclusion
that the major non-biting activity was associated
with gathering herbage prior to biting, rather
than with mastication during grazing or manipula-
tion of severed forage in the mouth prior to
swallowing. Legume percentage in extrusa was

54

higher when ingestive behavior involved an in-
crease in manipulative activity.

In general, our data suggested that intake per
minute was more closely related to bite weight
than to bites per minute, or to the proportion of
jaw movements which were bites. Similar results
were found by Chacon and Stobbs (1976) and Black
and Kenney (198^1). On the other hand, there was a
close relationship between legume percentage in
the diet and the proportion of jaw movements which
were bites. At the beginning of a grazing cycle,
therefore, intake rate and legume content of the
diet may be independent of each other and affected
by different characteristics of the canopy.

Canopy Character vs. Ingestive Behavior

Neither legume bulk density nor percentage in the
upper layer affected bite weight. The major
factor affecting bite weight was the percentage of
green herbage in the upper layer (r=.75). Intake
per minute was positively related to both the
percentage of green herbage in the upper layer
(r=.62) and to legume leaf as percentage of total
legume in the upper layer (r=.6l). Chacon et al.
(1978) and Jamieson and Hodgson (1979) found a
positive relationship between green herbage mass
and bite weight in grass pastures, and Hendricksen
and Minson (1980) found a similar relationship
with Lab lab puroureus. Ebersohn et al. (1985)
found a negative relationship between non-green
herbage and liveweight gain.

Total jaw movements per minute were not related to
any characteristic of the canopy. However, bites
per minute tended to increase as a result of
decreasing legume percentage, increasing weed
percentage, and increasing total leaf percentage
in the upper layer (multiple R'^=67.9). There was
a negative relationship between total herbage mass
and bites per minute (r=-.5^). There was a
negative relationship between percentage legume in
the upper layer and bites per 100 jaw movements
(r=-.68), indicating an increase in manipulative
activity when legume percentage was high. These
data suggest that at least part of the mechanism
of selection for legume (l.e., when legume in the
diet is a higher percentage than that in the upper
layer) may involve an increased gathering activity
prior to biting (severing) herbage.

Canopy Character vs. Diet Composition

In the extrusa, legume ranged from 1.3 to 93.4? of
DM and was positively related to legume percentage
in the upper layer (r=.85). In all but five
pastures, legume in the extrusa was equal to or
higher than that in the upper layer. Those five
pastures were sampled at the end of the season and
had high bulk density of weeds. When the five
most weedy pastures were eliminated, there was a
quadratic relationship between legume percentage
in the extrusa and in the upper layer (R^=.88).
When legume in upper layer was 40? or more, legume
in extrusa was 70? or more.

Legume percentage in extrusa was higher than that
in grazed horizon, but that in the herbage consum-

ed (as calculated by the difference method) was
almost identical to that in grazed horizon. The
following are correlations (R*^) among percent
legume in various fractions:

Consumed vs. Whole canopy .93

Grazed horizon .91

Upper layer .86

Esophageal vs. Whole canopy .49

Grazed horizon .55

Upper layer (Q) .67

Consumed .44

Laidlaw (1983) found that sheep continued to
select legume throughout the grazing period. In
our study, however, there was no evidence for
selection within the grazed horizon when the
entire grazing period was considered. Generaliza-
tions from results on one legume-grass association
to another might be misleading.

Cone lusions

In our study, there appeared to be at least two
separate phenomena at the plant-animal interface
when cattle first grazed the association; one
related to bite weight, the other related to
legume percentage of the diet selected.

Bite weight was lower when pastures were shorter
and more dense, and when there was a high propor-
tion of dead matter in the upper layer. These
conditions occurred primarily late in the season
when pastures had been grazed several times.

There was no effect, however, of legume percentage
in the upper layer upon bite weight, and bites per
100 jaw movements were not closely related to bite
weight .

Esophageal-fistulated animals consumed a diet with
a higher legume percentage than that found in the
upper layer of clipped sites in all but the most
weedy pastures. Our data and observations suggest
that steers responded to increased legume percen-
tage in the upper layer by increasing manipulative
activity prior to biting, i.e., decreasing bites
per 100 jaw movements and rate of biting. The
manipulation served to increase the percentage of
legume in each bite over that in the upper layer
of the canopy.

Legume percentage of consumed herbage, determined
by the difference method, showed evidence for
selection, in that legume percentage of consumed
herbage was higher than that of the whole canopy
prior to grazing. There was excellent agreement,
however, between the legume percentage of the
grazed horizon and that of consumed herbage. It
may be that, with this legume-grass association
under rotational management, cattle removed legume
leaf from the canopy first, then began to consume
whatever grass and legume remained in the graze-
able horizons. These data are evidence of a
dynamic plant-animal Interface in that canopy
characteristics influenced the diet quantity and
character, the act of consumption changed the
canopy, and animals responded by altering their
degree of selection. These observations may be

55

valid, however, for only this association studied
in this particular manner.

In comparing pasture sampling by using esopha-
geal-fistulated steers with use of the agronomic
or difference method, it appears that esophageal
samples are useful for "strategic" examination of
diets at particular times during rotational or
continuous grazing, whereas the difference method
is useful for obtaining an "integrated" sample of
herbage consumed during rotational grazing.

RECOMMENDATIONS

For those who consider conducting studies of the
plant-animal interface in grazed pastures, the
following recommendations should be considered:

1. Establish a strong justification for conducting
the study. Such studies are demanding, and
should not be undertaken without sufficient
reason.

2. Develop clear objectives for each particular
study, and design the trial to meet just those
objectives. Each study should try to answer a
specific question rather than synthesize broad
generalities .

3. Make an extra effort to measure important
response variables. Measure herbage mass, and
characterize the canopy profile thoroughly in
terms of botanical composition and bulk
density. Observe animal behavior carefully,
and make accurate counts of actual bites. It
is not always necessary to use esophageal-
fistulated steers for such measurements, and
observation of intact animals at frequent
intervals may be more meaningful than those
obtained during short collections. Use
esophageal-fistulated steers strategically to
measure diet composition and bite weight at
particular times during the grazing cycle. Use
large fistulas so that samples are representa-
tive of the diet consumed and so that bite
weight is not underestimated.

Literature Cited

Arnold, G. W. 1980. Grazing behavior. Iji (F. H.
W. Morley, Ed.) Grazing Animals. Elsevier,
Amsterdam, pp. 79-10^1.

Black, J. L., and P. A. Kenney. 1984. Factors
affecting diet selection by sheep. II. Height
and density of pasture. Aust. J. Agric. Res.
35:565-578.

Bohnert, E., C. Lascano, and J. H. Weniger. 1985.
Botanical and chemical composition of the diet
selected by fistulated steers under grazing on
improved grass-legume pastures in the tropical
savannas of Colombia. I. Botanical composition
of forage available and selected. Z.
Tierzuchtg. Zuchtgsbiol. 102:385-394.

Chacon, E. A., and T. H. Stobbs. 1976. Influence
of progressive defoliation of a grass sward on
the eating behaviour of cattle. Aust. J.

Agric. Res. 27:709-727.

Chacon, E. A., T. H. Stobbs, and M. B. Dale.

1978. Influence of sward characteristics on
grazing behavior and growth of Hereford steers
grazing tropical grass pastures. Aust. J.
Agric. Res. 29:89-102.

Chambers, A. R. M., J. Hodgson, and J. A. Milne.
1981. The development and use of equipment for
the automatic recording of ingestive behaviour
in sheep and cattle. Grass Forage Sci.
36:97-105.

Ebersohn, J. P., K. W. Moir, and F. Duncalfe.

1985. Inter-relationships between pasture
growth and senescence and their effects on
live-weight gain of grazing beef cattle. J.
Agric. Sci., Camb. 104:299-301.

Forbes, T. D. A., E. M. Smith, R. B. Razor, C. T.
Dougherty, V. G. Allen, L. L. Erlinger, J. E.
Moore, and F. M. Rouquette, Jr. 1985. The
plant-animal interface. Iq, (V . H. Watson and
C. M. Wells, Eds.) Simulation of Forage & Beef
Production in the Southern Region. Southern
Cooperative Series Bull. 308. pp. 95-116.

Hendricksen, R., and D. J. Minson. 1980. The
feed intake and grazing behaviour of cattle
grazing a crop of Lab lab puroureus cv. Rongai.
J. Agric. Sci., Camb. 95: 547-554.

Hodgson, J. 1982. Ingestive behavior. In (J. D.
Leaver, Ed.) Herbage Intake Handbook. Brit.
Grassl. Soc., England. Chapter 6, pp. 113-138.

Hodgson, J. 1985. The control of herbage intake
in the grazing ruminant. Proc. Nutr. Soc.
44:339-346.

Jamieson, W. S., and J. Hodgson. 1979. The
effects of variation in sward characteristics
upon the ingestive behavior and herbage intake
of calves and lambs under a continuous stocking
management. Grass Forage Sci. 34:273-282.

La id law, A. S. 1983. Grazing by sheep and the
distribution of species through the canopy of a
red clover-perennial ryegrass sward. Grass
Forage Sci. 38:317-321.

Ludlow, M. M., T. H. Stobbs, R. Davis, and D. A.
Charles-Edwards. 1982. Effect of sward
structure of two tropical grasses with con-
trasting canopies on light distribution, net
photosynthesis and size of bite harvested by
grazing cattle. Aust. J. Agric. Res.

33: 187-201.

Marten, G. C. 1981. Effect of deleterious

compounds on animal preference for forage and
on animal performance. In (J. L. Wheeler and
R. D. Mochrie, Eds.) Forage Evaluation:

Concepts and Techniques. American Forage and
Grassland Council, Lexington, KY. pp. 225-235.

56

Milne, J. A., J. Hodgson, R. Thompson,

W. G. Souter, and G. T. Barthram. 1982.

The diet ingested by sheep grazing swards
differing in white clover and perennial
ryegrass content. Grass Forage Sci.
37:209-218.

Minson, D. J. 1983. Forage quality: Assessing
the plant-animal complex. Proc. XIV
International Grassland Congress, Lexington,
KY. pp. 23-27.

Moore, J. E. 1983. Remarks of discussion
leader (see Minson, 1983). Proc. XIV
International Grassland Congress, Lexington,
KY. pp. 27-28.

Moore, J. E. , L. E. Sollenberger , G. A.

Morantes, and P. T. Beede. 1985. Canopy
structure of Aeschynomene americana -
Hemarthria altissima pastures and ingestive
behavior of cattle. Proc. XV International
Grassland Congress, Kyoto, Japan. (In press)

Penning, P. D., G. L. Steel, and R. H. Johnson.
1984. Further development and use of an
automatic recording system in sheep grazing
studies. Grass Forage Sci. 39:345-351.

Reed, K. F. M. 1981. A review of legume-based
vs nitrogen-fertilized pasture systems for
sheep and beef cattle. In (J. L. Wheeler
and R. D. Mochrie, Eds.) Forage Evaluation.
Concepts and Techniques. American Forage
and Grassland Council, Lexington, KY.
pp. 401-417.

Sollenberger, L. E., K. H. Quesenberry, G. 0.
Mott, and J. E. Moore. 1985. Effects of
grazing management on production and forage
quality of a limpograss-jointvetch
association. Proc. Forage and Grassland
Conf . , American Forage and Grassland Council
Hershey, PA. pp. 79-83.

Waldo, D. R. 1986. Effect of forage quality
on intake and forage-concentrate inter-
actions. J. Dairy Sci. 69:617-631.

SUMMARY OF REGIONAL PROJECT S-156, SIMULATION
OF FORAGE AND BEEF PRODUCTION IN THE SOUTHERN
REGION

L. M. Tharel\ M. A. Brown\ and E. M. Smith^

Approximately 25.0 million hectares of
pastureland and native pasture, and about 50%
of the nation's beef cattle are located in the
South. The value of production for beef cattle
in recent years exceeds 7 billion dollars
annually. Pasturelands are most often
associated with beef production systems and
most beef animals begin and spend the majority
of their time on pastures. Forage crops are
basic elements of pastures and constitute the
primary feed source for beef cattle. (Little,
1985) .

The management of these pastures and the beef
animals which utilize the feed produced by
these pastures is an important issue in
planning and executing beef cattle production
systems. Research should provide the
fundamental knowledge which can be used as a
basis for developing management stratgegies
which have the highest probability of success
in particular situations. There are literally
as many production systems as there are beef
producers, and for each of these systems there
are many management strategies which need to be
evaluated in order that producers in each
situation can effectively utilize resources to
produce feed for animals and produce a
marketable product. The use of traditional
field experiments to evaluate a large number of
management strategies (Smith and Williams,

1973) simultaneously for many different
production situations (Tseng and Mears , 1975)
is impractical, because such experiments would
require an enormous commitment of money, land,
and scientific man-years (Smith, et. al.,

1985) .

Research has contributed significantly to the
development of forage-beef production systems
and much research continues to be directed
toward current problems and potentials. With
the importance of forage-beef production,
attention continues to be directed to
evaluating past research, identifying and
prioritizing new research and increasing the
flow of results toward application. Excellent
results from much good research are available.
Systems research in agriculture has advanced
less than have industrial and commercial
applications. Possibly because of the size and
diversity of the agricultural sector and the
predominance of small owner-operated farms
(Dent and Blackie, 1979). Scientists and
producers have consistently identified an

Agricultural Research Service, U.S. Department
of Agriculture, South Central Family Farm
^Research Center, Booneville, Arkansas.
Agricultural Engineering Department,

University of Kentucky, Lexington, Kentucky.

increasing need for putting the pieces together
so as to understand better the entire
forage-beef production system. Climatic, soil,
and economic conditions in the Southern Region,
although varied, present great opportunities
for forage production throughout most of the
year. These conditions, problems and
opportunities presented a special situation for
interaction between scientists from several
disciplines to work together in a coordinated
effort. In July 1978 a Southern Region
Livestock-Forage Review Committee identified
this situation and stated;

"Systems research is needed to delineate and
solve the problems associated with different
1 ivestock- forage production systems and to
determine income-producing capabilities of the
different systems. Systems research is needed
to determine the performance of
livestock- forage systems when they interact
with various resource and management
constraints. Computer technology can now allow
for the development of a simulation model of
the complicated interrelations of the many
variables within the system. A simulation
research model, properly validated by data from
specific research projects, can be used as an
artificial laboratory to study livestock-forage
production systems. The information generated
by such a model will point up the 'gaps' in the
research data that are needed to be part of any
management decision concerning the ^
livestock-forage production systems."

Southern Cooperative Regional Project S-156 was
initiated in January 1981 to speak to this
expressed need with the following general
objectives :

1. To refine mathematical-logical
relationships currently existing in a
comprehensive systems model, so that the
model can be used in the southern region.

2. To facilitate use of the comprehensive
systems model to obtain new knowledge
concerning forage-beef production within
the constraints imposed by the resources
in the Southern Region.

The S-156 project entitled "Simulation of
Forage-Beef Production in the Southern Region",
involved scientists with specialization in
Agronomy, Animal Science, Agricultural
Economics, Agricultural Engineering, Statistics
and Veterinary Entomology from 10 State
Agricultural Experiment Stations and four
USDA-ARS Laboratories. Considerable time has
been spent interacting in groups and subgroups
to conceptualize forage-beef production
systems, to assimilate the results of basic
research defining the entities and sub-entities

^Recommended Adjustments in Livestock-Forage
Research in the Southern Region - Report of
the Livestock-Forage Review Committee,

Southern Region, U.S. A. July 1978, p2l.

58

which interact, to construct mathematical
logic, incorporating this knowledge into
simulation models and to evaluate these
simulations in "real world" comparisons.
Individual participants have authored numerous
publications in the professional journals of
their disciplines. Vacuums of knowledge
critical to refining forage-beef production
systems have been and are being identified and
incorporated into specific projects by one or
more discipline groups. Approximately a dozen
states have set up the mechanics for using the
simulation models for program planning and
evaluation and for education and training
experiences (Little, 1985).

As a result of the Regional emphasis, plant and
animal sub-models were developed. As the
sub-models were developed, they were in some
instances, incorporated. Loewer and Smith
(1986) have briefly characterized the models
which are a result of S-156.

GROWIT (Version 2) - This is a model of plant
growth that utilizes maximum and minimum
temperature, rainfall, soil fertility,
harvesting and other cultural practices in
describing plant growth. It simulates grazing
rate through various harvesting options.

Version 2 of GROWIT is more basic to plant
growth physiology and incorporates cell content
and cell wall logic with plant physiological
age to define potential digestibility.

BEEF-S156 - This model is based on the concept
of physiological growth as expressed through
changes in body composition. Intake may be
altered by control mechanisms associated with
thermostatic and chemostatic limits, physical
fill, and night-time limits. The time step is
a user-defined input but is usually not greater
than 15 minutes.

GRAZE - The GRAZE model incorporates selective
grazing logic with the plant growth concepts of
GROWIT (Version 2) and the animal growth
concepts of BEEF-S156. GRAZE utilizes
selective grazing logic that allows the animal
to graze partial areas within a pasture. The
basic assumptions are that a grazing animal
will attempt to maximize its digestibility dry
matter intake rate, and that total dry matter
availability per unit area of land will, at
some point, begin to limit intake rate. The
GRAZE model has received testing using field
studies from Mississippi and Georgia, and the
model is performing well in both instances.

Companion animal models developed as graduate
theses projects in Agricultural Engineering at
the University of Kentucky include BEEFEM and
SAM.

BEEFEM is a finite element model of the
interior of a beef animal that simulates the
flow of heat as influenced by environment,
activity, and digestion. This model was
calibrated and tested using beef animals with
implanted temperature devices in environmental

chambers. Contaminated fescue was fed as one
of the test rations. The model indicates that
vasoconstriction may be the mechanism that
limits intake for animals fed this ration.

SAM - SAM is a static model that utilizes body
measurements and geometric shapes in
determining beef animal surface area. The
purpose of the model is to enhance the ability
to describe heat flows to and from the animal.
This model was superior to the most commonly
used empirical models over the age range of
animals tested.

PASTURE - PASTURE is the most recent update of
GROWIT (Version 2). It has been structured
specifically for stochastic simulation of
grazing systems. In structuring this model,
special consideration has been given to keeping
the input data file brief, yet, allow
sufficient flexibility to adequately describe
different grazing management systems. In
addition, the data output file was simplified
to enhance data management and analysis. The
model logic used in the simulation of potential
tissue production is based on ruminant protein
requirements (ARC, 1980) and digestible dry
matter and dietary nitrogen adapted from a
model by Greenhalgh (1981).

The model is structured to allow grazing
systems to be described in terms of 1) number
of fields, 2) rotation period in days, 3)
simulated grazing rate in kg/ha/da or Ib/ac/da,
and number of grazing periods per year and the
date when each period begins and ends. It
allows for hay harvesting at specified times
and moisture to be supplied thru irrigation on
a specified schedule.

Real weather data provide stochastic variables
and any number of consecutive years of weather
data can be used as input data. These
stochastic variables allow simulations to be
replicated, consequently, simulation results
may be subjected to statistical analysis.

To conduct a simulation experiment the same
thought process is used as if an actual
experiment were to be conducted. There are
specific initial parameters which must be
defined .

INPUTS FOR PASTURE MODEL TO SIMULATE ON
EXPERIMENT

- Period of Study; first and last year,
duration of study

Lattitude of Site
Fields; number, day(s) on each
Grazing Period; number, day(s) of each,
beginning and ending date(s)

Interval between Data Collections

- Cattle; weight, number per ac or ha
Harvest Efficiency

Grazing Rates

- Dry Matter Remaining after Grazing
Climatic Data; precipitation and temperature
( max . , min . )

59

- Irrigation Schedule; number, frequency,
quantity, date(s)

Soil Test Data

Fertilization; N,P,K, date(s), quantity
Hay Harvest; date(s)

MODEL APPLICATION

St. Louis et. al. (1985) stated that models can
be important aids in designing systems research
projects by simulation of several forge-beef
systems before field trials are initiated. The
economic feasibility of alternative systems can
be verified, sensitivity and variation of
production components can be determined, and
important voids in the data base can be
identified. Much former research would have
broader application if data specific to the
environment and management of the project had
been reported.

Parsch et. al (1986) conducted a simulation
experiment to analyze the impact of weather
variability on the economic performance of a
beef-forage grazing system. Three stocking
rates 2, 7 and 12 hd/ha and 10 years of
historical weather data were included as
variables. The results indicated that 12 hd/ha
produced the highest gain per ha while gain/hd
was maximized with the lowest stocking rate, 2
hd/ha; expected net returns per ha were highest
under the medium stocking rate; and, the
adverse effects of a poor weather season were
magnified at the higher stocking rate. Ranking
of the three stocking rate strategies showed
that the low stocking rate is the most
risk-efficient, whereas the medium stocking
rate maximizes expected utility of producers
who are risk neutral.

St. JjOuis et. al. ( 1985) further stated that
the plant and animal submodels, or components
can be run separately, which makes it possible
to study and better understand fundamental
relationships that would be very difficult to
study without simulation. For example, the
model can simulate physiological and
chronological age relationships as they relate
to plant and animal growth. Since cell-wall
content and cell-wall maturity are incorporated
as quality indicators in the plant submodel,
one can study the combined effects of
environment and maturity on forage yield and
digestibility. Furthermore, the effects of
environment on plant-related determinations of
forage quality can be separated from the
influences of environment on animal
determination of intake, digestibility and use.
The animal submodel is a body composition
model, thus making it possible to study the
combined effects of environment, age, fat
storage and nutritional status on animal
growth, reproduction, lactation and gestation.

As strategies for meeting management objectives
are found through simulation, scientists and
managers also will develop an improved
understanding of key variables. For example,
each management strategy of a forage-beef

production system may result in a different
seasonal distribution of feed supply (quantity
and quality), which results in seasonal
variation in beef production. This may in
turn, lead to more efficient resource
substitution, such as purchasing of feed
supplements. Regional and annual differences
in temperature, rainfall, forage production,
etc. can all be taken into consideration when
optimum management strategies are determined.
The crop growth component can simulate growth
of warm- and cool-season perennial grasses
alone or in combinations, resulting in broad
applications of management strategies across
the Southern Region. Similarly, the animal
component can consider breed differences and
influences of weather on animal performance
independent of forage quality and availability.

Fick and Onstad (1983) state that models of
complex systems are never complete, but they
can be used to satisfy specific and reasonable
objectives. Models designed for tasks can be
improved, extended, modified, updated and
simplified to achieve new and different
objectives. Because our understanding of
forage-livestock systems is limited, all models
contain elements based on extrapolation,
interpolation and algorithms. As research,
possibly directed by systems research, expands
knowledge in these areas, approximations can be
supplanted by quantitative information. We can
expect forage- 1 ivestock models to expand and
then contract in size as sensitivity analysis
weeds out the non-limiting factors, spinning
off simpler models that can be used in an
interactive mode on microcomputers.

Barnes et. al. (1985) emphasized that
mathematical models cannot replace the
judgement of experienced people nor can they
analyze cause and effect relationships that
cannot be quantified. The effectiveness of
systems modeling and its application to
agriculture depends upon the accuracy,
comprehensiveness, and ease of the systems
models. We are on the threshhold of a new
frontier of science that presents a challenge
to agricultural scientists and administrators
to integrate available knowledge into
comprehensive research programs for solving
short- and long-term problems.

Literature Cited

ARC. 1980. The nutrient requirements of

ruminant livestock. Commonwealth Agricul-
tural Bureaux, Farnham Royal, Slough 2L2 ,
3BN, England.

Barnes, R. F. , C. 0. Little, and M. A. Brown.
1985. Influence of systems modeling on
agricultural policy. ^ V. H. Watson, and
C. M. Wells (Ed.), Simulation of Forage and
Beef Production in the Southern Region. So.
Cooper. Series, Bull. 308. Miss. St. Univ.,
Miss. St. MS. pp. 133-134.

60

Dent, J. B. and M. J. Blackie. 1979. Systems
simulation in agriculture. Applied Science
Publ. LTD. London.

Pick, G. W. , and D. Onstad. 1983. Simulation
models for forage-management applications.

In J. A. Smith and V. W. Hays (Ed.), Proceed
ings of the XIV International Grassland
Congress, Westview Press, Boulder, CO,
pp. 483-485.

Greenhalgh, J. F. D. 1981. A forward look at
technical possibilities for grassland.
Grassland in the British Economy. CAS Paper
10. Reading: Center for Agricultural
Strategy, pp. 51-63.

Little, C. 0. 1985. Introduction. Iri V. H.
Watson, and C. M. Wells (Ed.), Simulation of
Forage and Beef Production in the Southern
Region. So. Cooper. Series, Bull. 308. Miss
St. Univ., Miss. St. MS. pp 1-2.

Loewer, 0. J. and E. M. Smith. 1986.

Biological description of the Kentucky beef-
forage model. ^ D. Laughlin and T. Spreen
(Ed.), Simulation of Beef Cattle Production
Systems and its Role in Economic Analysis.
Westview Press, Boulder, CO. (In press).

Parsch, L. D., 0. J. Loewer, and D. H. Laughlin
1986. Risk efficiency of beef-forage stockr
ing rates under weather uncertainty. Jji
D. Laughlin and T. Spreen (Ed.), Simulation
of Beef Cattle Production Systems and its
Role in Economic Analysis. Westview Press,
Boulder, CO. (In press).

Smith, E. M. , L. M. Tharel, M. A. Brown, C. T.
Dougherty, and K. Limbach. 1985. A
simulation model for managing perennial
grass pastures. Part I - Structure of the
model. Agri. Systems. 17, pp 155-180.

Smith, R. and W. A. Williams. 1973. Model
development for a deferred grazing system.

J. Range Mgmt . 26, pp. 454-460.

St. Louis, D. G. , B. W. Spaulding, 0. J.

Loewer, and V. H. Watson. 1985. Applica-
tions and limitations of modeling forage
and beef. Jut W. H. Watson, and C. M.

Wells (Ed.), Simulation of Forage and Beef
Production in the Southern Region. So.
Cooper. Series, Bull. 308. Miss. St. Univ.,
Miss. St. MS. pp 131-132.

Tseng, W. and D. R. Meats. 1975. Modeling
systems for forage production. Trans.

ASAE, 18, pp. 206-212.

APPROPRIATE MARKERS AND METHODOLOGY FOR GRAZING
STUDIES

K. R. Pond^, J. C. Burns^, D. S. Fisher^ and R.
A. Quiroz^

Evaluation of the grazing animal's diet,
requires measurement of both the voluntary
intake of forage and its nutritive value.
Appropriate markers (indicators) have been used
to provide information on forage utilization by
the animal. Markers have been used to
determine forage digestibility, output of feces
by the animal, rate of passage (liquids and
solids) through the gastrointestinal tract,
fill of undigested dry matter and rate of
particle size breakdown. The purpose of this
paper is to briefly review many of the
available markers and recommend procedures for
their use in grazing studies. The literature
cited should be reviewed for more detailed
information.

TYPES OF MARKERS

Markers may be catagorized as internal or
external. Internal markers are natural
constituents of the plant that are neither
digested nor absorbed by the animal. Examples
include silica, lignin, fecal nitrogen
(indigestible nitrogen), chromogens,
indigestible neutral detergent fiber and acid
insoluble ash.

External markers are not natural constituents
of the forage but must also not be digested or
absorbed. These markers are fed or
otherwise administered to the animal. Examples
include chromic oxide, ferric oxide, silver
sulfide polyethylene glycol and preparations of
chromium, cobalt, hafnium and several rare
earth metals.

Internal markers

Internal markers are most commonly used to
estimate digestibility. The marker
concentration is determined in both the
consumed forage and feces. The dry matter
digestibility (DDM) is then calculated from the
ratio of the marker in the forage ^.^Qg) and
feces (Mfeces^ (Schneider and Flatt, 19/5):

^Department of Animal Science, N.C. State
University, Raleigh, NC 27695-7621

^Agricultural Research Service, U. S.
Department of Agriculture, Plant Science
Research Unit and Department of Crop Science,

N. C. State University, Box 7620, Raleigh, NC
27695-7620.

^ forage

DDM, % = 100 - (100 X 1-)

% M

feces

(1)

The digestion coefficient (DC) of any nutrient
can also be estimated by determining the ratio
of the nutrient to that marker in the forage
(N

forage^ feces (N^rg^^gg).

DC, % = 100 - (100 X-

^'forage ^ ^ ^feces

■) (2)

*^feces ^ ^ '^forage

Several internal markers have been researched
and are described below.

Silica - Naturally occurring silica in
forage is indigestible and recovered in the
feces. Silica concentration in the forage has
been variable and inconsistent especially in
areas where significant soil contamination of
the forage is a problem. In addition, poor
recovery of silica in the feces has limited its
use as an internal marker (Gallup et al.,

1945). Silica from soil contamination must be
estimated and removed from calculations of DDM
and DC.

Lignin - The naturally occurring
indigestible portion of the cell wall and
middle lamella of forage has been used as an
internal marker with reliable results for some
species of plants. Ellis et al. (1946) was the
first to propose its use as a marker and its
gravimetric analysis after 72% H2S0^
extraction. Diurnal variation in lignin
concentration in the feces can be high, so many
samples need to be collected. Reducing the
variability in the analysis of this
heterogeneous polymer may require analysis of
the individual components rather than the
present gravimetric procedures for total
1 i gni n .

Fecal nitrogen - Holter and Reid (1959)
studied the relationship between protein in the
feces and digestibility with 79 forages. They
concluded that the true digestibility of
protein is relatively constant regardless of
the concentration of crude protein in forages.
Sneider and Flatt (1975) then developed an
equation to determine the digestibility of dry
matter utilizing crude protein in forage and
feces. This equation has not been evaluated
for many forage species.

Chromogens - Plant pigments, "chromogenic
substances", are soluble in 80% acetone.
Concentrations are determined spectrophotomet-
rically and are completely recovered in the
feces. This method is described by Reid et al.
(1950 and 1952). Chromogens, as markers, seem
to be best fitted to lush growing forage and
least effective for drought or temperature
stressed poorly pigmented plant tissues.

Indigestible neutral detergent fiber (INDF)

The neutral detergent fiber residue after in
vitro fermentation for 144 to 196 h has been

62

used as an internal digestibility marker
(Lippke et al., 1986). Variable recovery of
INDF and a "recovery x particle size"
interaction are potential problems with the
technique. However, several investigators have
utilized INDF as a marker in grazing studies.

Acid insoluble ash (AIA) - The insoluble
ash after acid hydrolysis (Thoney et al. 1985)
has been used as an internal marker in feedlot
diets and with animals consuming Coastal
bermudagrass. The concentration of AIA in most
forages is low. Therefore, the sample of
forage and feces required for the analysis is
larger than with other markers (10-25g
required) .

An infallible and dependable internal marker is
not available at this time. Of these markers,
lignin has been the most widely used. In our
lab, components of lignin resistant to strong
alkali hydrolysis are being evaluated as
possible internal markers. A reliable incernal
marker would be a significant contribution to
the understanding of plant-animal dynamics in
graz i ng research.

External markers

External markers have been most frequently used
to estimate output of feces. With knowledge of
the dry matter digestibility (DDH) of the
forage, the voluntary intake (VI) of the animal
can be calculated:

Yj - dry matter output of feces, g/d (3)

1 -(DDM/lOO)

Although the total output of feces can be
collected with a fecal bag and collection
harness, it is laborious and unsatisfactory for
most grazing studies (especially during the
spring or when forage quality is high).
Alternatively, fecal output can be computed
without total collection by using indigestible
markers. There are two methods: daily marker
administration to generate a steady state or
single (pulse) dose administration.

In the first method, daily administration of a
known quantity of a marker is followed by
periodic sampling of feces. The marker
concentration in the feces is then determined.
Equilibrium (steady state conditions) of the
the marker, requires administration for at
least five days prior to sampling. Grab
samples of feces should be collected over 3- to
7-days to obtain a mean marker concentration.
Diurnal variation has been reported for several
markers so multiple sampling times are
required. Fecal output (FO) is then calculated
as follows:

PQ _ marker administered, pg/d (4)

marker concentration in feces, pg/g

This procedure has the disadvantages of a daily
labor requirement for marker administration.

the possible injury to animals during
administration and problems in maintaining
daily marker intake.

In the second method, output of feces is
estimated from the change over time in marker
concentration following a single administration
of the marker (figure 1). There is a time delay
between administration and first appearance in
the feces and then the concentration increases
to a peak followed by a decrease to below
detectable limits.

Time after dose

Figure 1. Concentration of marker in the feces
after oral administration.

A major disadvantage of this method is the
required frequency of fecal collection to
obtain the curve in figure 1. Several 1- and
2- compartment models have been developed to
describe the marker appearance curve (Pond et
al., 1984). In most grazing studies the one
compartment model with time delay and gamma two
age dependency has given the best fit. The
model is:

y = (kg X X3 (t-td) X e”^^l ^ 59635

where y = concentration of marker,
kg = concentration of marker if
instantaneously mixed in the compartment,
A, = age dependent rate paramerter,
to = time delay,

t = time after marker administration.
Output of feces (FO) is then computed as:

FO, g/d = Marker dosed, g/d x x 24 x 0.59635
•^0

In addition to fecal output the mean retention
time (MRT) of the marker and fill of undigested
dry matter in the digestive tract (fill) can be
determi ned:

MRT, h = 2/Xp + td
fill g = niarker administered

ko’ pg/g

This additional information cannot be
calculated when marker is administered daily.
Several indigestible external markers have been
utilized and are described below.

63

Chromic oxide {Cr^03) - The oldest and most
commonly used marker is chromic oxide powder.
Chromic oxide is water insoluble and is
associated with neither the solid (particle)
nor liquid components of digesta. This lack of
association can result in sedimentation in the
rumen and sporadic transfer through the
gastrointestinal tract (Ellis et al., 1982).
Part of this problem has been reduced with the
incorporation of Cr203 into paper or cellulose.
The shreaded paper is then administered to the
animal. The movement of Cr203 incorporated on
paper is more representative of digesta
particles than Cr203 powder. However,
availability of this paper product is low.

Diurnal variation in the excretion of Cr203 is
a normal phenomenon in ruminants and can
increase variation in chromium concentration in
the feces (Hardison and Reid, 1953).

Therefore, samples must be taken that represent
several time periods.

Ferric oxide - As with chromic oxide,
ferric oxide may accumulate in the rumen and
may not remain completely mixed with digesta.
Variable and poor recovery has reduced its
popularity as a marker in ruminants (Pond et
al., 1985).

Silver sulfide (Ag2S) - The sulfides of
several heavy metals have been evaluated as
markers. Silver sulfide is insoluble in the
digestive tract, recoverable in the feces and
analytically determined with great accuracy.
However, expense has limited its use as a fecal
output marker (Schneider and Flatt, 1975).

Chelated minerals - Chelation products of
Chromium, colbalt and several rare earths with
ethylenediaminotetraacetic acid (EUTA) or
diethylenetri ni tri lopentaacetic acid (DTPA)
have been used as indigestible markers (Ellis
et al., 1982). These chelation products are
water soluble and presumably follow the flow of
solubles through the gastrointestinal tract.
Some binding of Cr-EDTA to particles in the
rumen has been reported.

Polethylene glycol (PEG) - This material is
extremely water soluble and nearly completely
recovered in che feces. Analytical procedures
are poor and problems have been noted with
feeds high in tannins (PEG precipitates) (Ellis
et al., 1982). This has reduced its popularity
as a marker of liquids.

Chromium mordated fiber - To measure the
flow of fiber through the gastrointestinal
tract requires that the marker remain
associated with the fiber. The chromium
mordant procedure was developed (Uden et al.,
1980) to attach chromium to the forage fiber
with it remaining bound throughout the ruminant
digestion process. The procedure calls for
adding chromium equal to 12-14% of the weight
of the fiber. At this high level, the density

of the fiber is increased and passage of the
marked fiber may be different than that of the
unmarked fiber (Ehle et al., 1984). To
minimize this problem, this procedure has been
altered in our laboratory so that chromium is
added at a rate of 6-8% of the fiber weight.

At present, this is the most widely used fiber
marker.

Rare Earth labeled fiber - The rare earths
including lanthanum, cerium, europium,
samarium, neodymium, dysprosium, erbium,
terbium and lutetium and the elements hafnium
and scandium, have been used to mark fiber.

The procedure for labeling the fiber has
evolved from sprinkling of a water soluble
marker solution on the fiber to soaking the
marker solution and washing the fiber to
binding the marker at different pHs with EDTA.
The rare earths are not as tenaciously bound in
the soaking procedure to the fiber as occurs in
the mordanting process. This procedure has
been criticized because of possible marker
transfer to unlabeled fiber and possibly to the
liquids (Ellis et al., 1982).

MARKER APPLICATIOKS IN GRAZING STUDIES

To predict intake on pasture using markers
requires that the quality of the forage
consumed by the animal be estimated. This
requires additional sampling regardless of the
marker or marker procedure used. Simply using
forage yield samples or cuttings will not
likely account for the selection exhibited by
the animal. To obtain a representative sample
of the selected forage the use of a rumen or
esophageal cannulated animal is recommended.
Forage selected by grazing animals can be
readily obtained by using an animal fitted with
an esophageal cannula. Hand plucked samples
are an alternative where surgically modified
animals are not available.

Digestibility of forage representing the
animal's diet can then be estimated either by
an in vitro (Burns and Cope, 1974) analysis or
by using an internal marker. Best results from
markers have been obtained with INDF or lignin
usi ng equati on (2).

Estimates of fecal output are more difficult to
obtain. If the trial involves supplementation
with grain, a marker can be administered to the
animal as part of the grain portion. Chelates
of erbium, chromium, cobalt and dysprosium have
been added in liquid form to the supplement,
allowed to dry and individual allowances
weighed out to be fed once or twice daily.
Animals must be individually fed and all of the
marker must be consumed. Fecal output is then
estimated from the mean of representative
samples using equation (4).

Most grazing studies do not involve grain
supplementation and do not utilize individual
feeding stalls. Therefore, the marker must be
administered daily to the animal by dosing.

64

Dried marked fiber (sometimes using rice hulls
as a carrier) is usually dosed with a balling
gun. Liquid marker can be administered orally
with a syringe. Ellis (1978) developed a pump
to deliver a set amount of marker at prescribed
times. The device fits inside the lid of a
rumen cannula and has been used successfully.

If the daily administration technique is used
and the pasture area is small, care must be
exercised to avoid contaminating the pasture
with the marker. Such contamination will
markedly reduce the measured output of feces.
This has happened after using chromic oxide as
the daily dose marker on the same pasture for
several years.

The technique we have found most workable and
reliable is the single marker administration
and fecal sampling to obtain the saturation-
desaturation curve presented in figure 1.
Generally, both a liquid marker (cobal t-EDTA)
and a particle marker (chromium mordated fiber)
are dosed. From this curve, the output of
feces along with the rate of passage, mean
retention time and gastrointestinal tract fill
are estimated. Animals are dosed at 600-700 h
and sampled at 5, 9, 13, 17, 24, 28, 31, 35,

38, 41, 48, 55, 61, 72, 79, 85, 97 and 109 h
postdosing. Two sampling periods (h 17 and 41)
occur at 2300 h (after dark). Samples are
obtained by following animals until they
defecate and spooning the feces into prelabeled
plastic bags or by moving animals to a squeeze
chute for rectal grab sampling. Night time
sampling is facilitated by miners head lamps.

The cobalt and chromium in the feces are
extracted with acid (Quiroz, 1984) and assayed
by atomic absorption spectrophotometry. Other
potential markers to be assayed by atomic
absorption (in decreasing sensitivity) are
ytterbium, erbium and dysprosium. The use of
neutron activation analysis greatly increases
analytic sensitivity and the number of
potential markers (Pond et al., 1985).

Literature Cited

Burns, J. C., and Cope, W. A. 1974. Nutritive
value of crownvetch forage as influenced
by structural constituents and phenolic and
tannin compounds. Agron. J. 66:195-200.

Ehle, F. R., Bas, F., Barno, B., Martin, R.,
and Leone, F. 1984. Particulate rumen
turnover rate measurement as influenced by
density of passage marker. J. Dairy Sci.
67:2910-2913.

Ellis, G. H., Matrone, G., and Maynard, L. A.
1946. A 72 percent H^SO^ method for the
determination of ligmn and its use in
animal nutrition studies. J. Anim. Sci.
5:285-297.

Ellis, W. C. 1978. An improved portable rumen
infusion pump for grazing research. J.
Anim. Sci. (Suppl 1):47:292.

Ellis, W. C., Lascano, C. E., Teeter, R., and
Owens, F. N. 1982. Solute and particulate
flow markers, pp. 37-56. In Protein
requirements for cattle: Symposium. MP-109
Oklahoma State University.

Gallup, W. D., Hobbs, C. S., and Briggs, H. M.
1945. The use of silica as a reference
substance in digestion trials with
ruminants. J. Anim. Sci. 4:68-71.

Hardison, W. A., and Reid, J. T. 1953. Use of
indicators in the measurement of the dry
matter intake of grazing animals. J. Nutr.
51:35-52.

Holter, J. A., and Reid, J. J. 1959.

Relationship between the concentrtion of
crude protein and apparently digestible
protein in forages. J. Anim. Sci. 18:1339-
1349.

Lippke, H., Ellis, W. C., and Jacobs, B. F.
1986. Recovery of indigestible fiber from
feces of sheep and cattle on forage diets.
J. Dairy Sci. 69:403-412.

Pond, K. R., Ellis, W. C., and Matis, J. H.
1984. Development and application of
compartmental models for estimating various
parameters of digesta flow in animals.

Texas A a M University, Department of
Animal Science Technical Report 84-2.

Pond, K. R., Ellis, W. C., James, W. D., and
Deswysen, A. G. 1985. Analysis of
multiple markers in nutrition research. J.
Dairy Sci. 68:745-750.

Quiroz, R. A. 1984. Particle size of forage
masticate and its effect on digestion, rate
of passage, and intake by goats. MS
Thesis. N. C. State University.

Reid, J. T., Woolfolk, P. G., Richards, C. R.,
Kaufmann, R. W., Loosli, J. K., Turk, K.

L., Miller, J. I., and Blazer, R. E. 1950.
A new indicator method for the
determination of digestibility and
consumption of forages by ruminants. J.

Dai ry Sci . 33 :6U-71 .

Reid, J. T., Woolfolk, P. G., Hardison, W. A.,
Martin, C. M., Brundage, A. L., and
Kaufmann, R. W. 1952. A procedure for
measuring the digestibility of pasture
forage under grazing conditions. J. Nutr.
46:255-269.

Schneider, B. H., and Flatt, W. P. 1975. The
evaluation of feeds through digestibility
experiments. The University of Georgia
Press, Athens, Georgia.

65

Thoney, M. L., Palhof, B. A., DeCarlo, M. R.,
Ross, D. A., Firth, N. L., Quass, R. L.,
Perosio, D. J., Duhaime, D. J., Rollins, S.
R., and Nour, A. Y. M. 1985. Sources of
variation of dry matter digestibility
measured by the acid insoluble ash marker.
J. Dairy Sci . 68:661-668.

Uden, P., Colucci, P. E., and Van Soest, P. J.
1980. Investigation of chromium, cerium
and cobalt as markers in digesta rates of
passage studies. J. Sci. Food Agric.
31:625-631.

66

BUSINESS MEETINGS AND RELATED MATTERS Resolution I.

Forty-second Southern Pasture and Forage Crop
Improvement Conference
Athens, GA 30602
16 April 1986

Minutes of the Business Meeting

Dr. Wilfred McMurphy, Chairman, called the
meeting to order at 4:30 p.m. Because SPFCIC
met jointly with the American Forage and
Grassland Council, the usual format was not
followed. The business meeting began with a
roll-call of states.

A financial report was made by R. S.

Kalmbacher indicating that $2664.63 was in the
account in Wauchula, Florida. Motion was made
by Harlan White, seconded by Paul Mueller
to accept the treasurer's report. Passed.

A motion was made by Joe Burns to accept the
minutes of the 4Ist meeting as published in
the 4Ist Proceedings. Seconded by Don Ball.
Passed .

A report was made by nominations committee
(composed of Harold Brown (Georgia) chairman,
Harlan White (Virginia), and R. S. Kalmbacher
(Florida)). They placed the name of Warner
Essig (Mississippi) for chairman, elect-elect.
There were no nominations from the floor.

Joe Burns moved nominations be closed, seconded
by Lee Mason. Warner Essig was elected by
acclamation. Jim Green was nominated for
secretary-treasurer (three year term 1987-1989).
There were no nominations from the floor.

Billy Nelson moved that nominations be closed;
seconded by Charles Ruelke. Jim Green was
elected by acclamation.

A report was made by Billy Nelson (chairman)
of the resolutions committee. Lee Mason and
Joe D. Burns also composed this committee.

A copy of the Resolution No. 1 is attached.

A motion was made by Wade Faw to accept
Resolution No. 1 recognizing the staff and
administration of the University of Georgia,
seconded by Joe D. Burns. Passed. A second
resolution (attached) recognizing the
contributions of John Miller, Coastal Plain
Experiment Station. A motion to accept the
Resolution No. 2 was made by Roy Blazer,
seconded by Don Ball. Passed.

A letter from Glenn B. Collins, Associate
Dean for Research for the University of
Kentucky, invited the 44th SPFCIC to meet in
Kentucky in 1988. A motion to accept the
invitation was made by J. Paul Mueller,
seconded by K. Quesenberry. Passed.

The gavel was passed from Wilfred McMurphy to
Hagen Lipke. With no further business, the
meeting was adjourned.

WHEREAS, membership of the 42nd Southern
Pasture & Forage Crop Improvement Conference
has gleaned much information and great benefits
from participation in the Conference, and

WHEREAS, such information and benefits
could not have been realized without the
friendly hospitable efforts of the staff and
administration of The University of Georgia
and US DA, ARS .

BE IT RESOLVED that the 42nd Conference
express grateful appreciation to the staff,
faculty, and administration of The University
of Georgia for their gracious hospitality,
imaginative programming, well-planned and
effective tour of the forage-animal research
facilities, and review of selected research
programs .

That special recognition be extended to Dr.
William Flatt, Dean, College of Agriculture,

Dr. Clive Donoho, Director, Georgia Agriculture
Experiment Station, Dr. William Colville, Head,
Department of Agronomy, Dr. David Spruill, Head,
Department of Animal Science, and Dr. Maurice
Frere, Director, USDA Southern Piedmont
Research Center, Watkinsville.

That signal recognition be extended to Dr. Carl
Hoveland and all members of the local arrange-
ments committee,

to Conference Chairman, Wilfred McMurphy;
Immediate Past -Chairman, Billy Nelson; and
Secretary, Robert Kalmbacher (Secretary since
1980) ,

to Session Chairmen, David St. Louis, Utiliza-
tion; Wade Faw, Extension; Gary A. Pederson,
Breeding; Geoff Brink, Ecology-Physiology,

to all who presented conference papers, and

to financial contributors toward conference
expenses .

Resolution 2.

WHEREAS, membership of the Southern
Pasture & Forage Crops Improvement Conference
has greatly benefited over the years, since
1981, from the contributions of John Miller,
Research Agronomist, Coastal Plain Experiment
Station, Tifton, Georgia, contributions
which have included assembling program papers
and related records into the Annual Proceedings
of the conference.

BE IT THEREFORE RESOLVED that the 42nd
Conference express grateful appreciation to
Dr. Miller for his unselfish and effective
service.

67

CONFERENCE REGISTRANTS

AKIN, D. E. , Russell Research Center, P. 0.

Box 5677, Athens,, GA 30613

,/^ELY, L. D., Dept, of Dairy Sci., University of
Georgia, Athens, GA 30602

ALBRECHT, K. A., Agronomy Dept., 305 Newell

Hall, University of Florida, Gainesville,

FL 32611

ESSIG, H. W. , Animal Science Dept., Mississippi
State University, Mississippi State, MS
39762

/ ALLEN, V. G., Dept, of Agronomy, VPI & SU,
Blacksburg, VA 24061

EVANS, J. K. , Dept, of Agronomy, N-222K

Ag . Science Bldg.-N, University of
Kentucky, Lexington, KY 40546

BAGLEY, C. P., West La. Exp. Sta., P. 0. Box 26,
Rosepine, LA 70659

EVERS, G. W., P. 0. Box 728, TAMU Agri. Res.
Station, Angleton, TX 77515

BALL, D. M. , Extension Hall, Auburn University,

AL 36849

FAW, W. F. , 255 Knapp Hall, Louisiana State
University, Baton Rouge, LA 70803

BALLERSTADT, P. J., Graduate Student, 740

Sims Road, Georgetown, KY 40324

FONTENOT, J. P., Dept, of Animal Sci., VPI & SU
Blacksburg, VA 24061

BALTENSPERGER, D., Agronomy Dept., University
of Florida, Gainesville, FL 32611

FRERE, M.H., USDA-ARS , P. 0. Box 555, Watkins-
ville, GA 30677

BARNES, R. F. , P. 0. Box 19227, New Orleans,

LA 70179

GERKEN, J., Animal Science Dept., VPI & SU,
Blacksburg, VA 24061

BELESKY, D. P., P. 0. Box 555, Watkinsville,

GA 30677

GOODROAD, L. L. , Dept, of Agronomy, University
of Georgia, Griffin, GA 30212

BLASER, R. E., Dept, of Agronomy, Virginia
Polytechnic Institute, Blacksvurg, VA

24061

GREEN, J. T., Dept, of Crop Science, Box 7620,
N. C. State University, Raleigh, NC
27695-7620

BOUTON, J. H., 3111 Plant Sci. Bldg., Univer-
sity of Georgia, Athens, GA 30602

HAALAND, R. , Sun Rise Seed Co., P. 0. Box 2085,
Auburn, AL 36830

BROWN, R. H. , Dept, of Agronomy, University
of Georgia, Athens, GA 30602

HANKINS, B. J., P. 0. Box 391, Little Rock,

AR 72203

BURNS, J., P. 0. Box 1071, University of

Tennessee, Knoxville, TN 37901-1071

HILL, G. M. , Dept, of Animal Sciences, Coastal
Plain Experiment Station, Tifton, GA
31793-0748

BURNS, J. C., Dept, of Crop Science, Box

7620, N. C. State University, Raleigh,

NC 27695-7620

HILL, N. S., Agronomy Dept., University of
Georgia, Athens, GA 306C2

BURRIS, R. , Research & Education Center,

University of Kentucky, P. 0. Box 469,
Princeton, KY 42445

HOVELAND, C. S., Dept, of Agronomy, University
of Georgia, Athens, GA 30604

^ BURTON, G. W. , Forage & Turf Rsch. Ctr.,

Georgia Coastal Plain Expt. Sta.,

IVY, R. L. , P. 0. Box 124, Prairie Experiment

Station, P. 0. Box 124, Prarie, MS 39739

Tifton, GA 31793-0748

JOOST, R. , Southeast Research Station, P. 0.
Drawer 567, Franklinton, LA 70438

CARR, S. B., 276 Animal Sci. Bldg., VPI,

Blacksburg, VA 24061

CHAMBLISS, C., Agronomy Dept., University of

KALMBACHER, R. S., AREC, Rt . 1, Box 62,

University of Florida - Agronomy, Ona, FL,
33865

Florida, Gainesville, FL 32611

a^COLEMAN, S. W. , USDA, ARS , Route 3, El Reno,

OK 73036

KAISER, C. J., Rt. 1, Box 132, Simpson, IL

62985

COLLINS, M. , Agronomy Dept., University of

Kentucky, Lexington, KY 40546

KIMBROUGH, E. L. , Agronomy Dept., Mississippi
State University, Mississippi State, MS
39762

^CONGER, B. V., Dept, of Plant & Soil Sci.,

Box 1071, University of Tennessee,

Knoxville, TN 37901-1071

KINCHELOE, S., International Minerals and
Chemicals, Agronomic Services, 421 E.
Hawley Street, Mundelein, IL 60060

68

i/^KING, C. C. , Jr., Dept, of Agron. & Soils,

Funchess Hall, Auburn University, AL

36849

PEDERSON, J., Agronomy & Soils Dept., Funchess
Hall, Auburn University, AL 36849

KNIGHT, W. E., Crop Sci. Res. Lab, P. 0. Box

PINKERTON, B., TAMU Agri. Res. & Ext. Ctr.,

2415 E. WHy 83, Weslaco, TX 78596

272, Mississippi State, MS 39762

LACEFIELD, G. D. , Research and Education Center,
University of Kentucky, P. 0. Box 469,
Princeton, KY 42445

.^^OND, K. R. , Dept, of Animal Science, Box 7621,

N. C. State University, Raleigh, NC
27695-7621

LIPPKE, H., P. 0. Box 728, TAMU Agri. Res.

Station, Angleton, TX 77515

POWELL, J. B., Russell Research Center, 170
Creekshore Drive, Athens, GA 30606

MASON, L. F., S. E. La. Dairy & Pasture Exp.

Sta. , P. 0. Drawer 567, Franklinton, LA

PRATT, J. N. , Soil & Crop Sci., Texas A&M

University, College Station, TX 77843

70438

MATCHES, A. G., P. 0. Box 4169, Texas Tech

PRINE, G. M. , Dept, of Agronomy, University of
Florida, Gainesville, FL 32611

University, Lubbock, TX 79401

MCCORMICK, M. E., LSU Southeast Res. Sta.,

QUESENBERRY, K. H., Dept, of Agronomy, Univer-
sity of Florida, Gainesville, FL 32611

Franklinton, LA 70438

MCCLAIN, E. F. , Dept, of Agron. & Soils,

Clemson University, Clemson, SC 29631

RASNAKE, M. , Research & Education Center,

University of Kentucky, P. 0. Box 469,
Princeton, KY 42445

MCMURPHY, W. E., Dept, of Agronomy, Oklahoma

REEVES, S. A., Jr., Box 220, Overton, TX 75684

State Univ., Stillwater, OK 74078

^^^✓^ILLER, J. D. , Agronomy Dept., Coastal Plain
Experiment Station, P. 0. Box 748,

REYNOLDS, J. H., Dept, of Plant & Soil Sci.,

P. 0. Box 1071, University of Tennessee,
Knoxville, TN 37901-1071

Tifton, GA 31793-0748

MISLEVY, P., AREC , Rt . 1, Box 62, University

RICE, H., Agronomy Specialist, Robinson
Substation, Quicksand, KY 41363

of Florida - Agronomy, Ona, FL 33865

MONSON, W. G., USDA Forage & Turf Rsch. Ctr.,

RICE, J. S., 277 P & AS Bldg., Clemson Univer-
sity, Clemson, SC 29631

Georgia Coastal Plain Station, Tifton,

GA 31793

MOORE, J. E. , Dept, of Animal Science,

ROBINSON, D. L. , Agronomy Dept., Louisiana State
University, 211 Parker Agriculture Center,
Baton Rouge, LA 70803

University of Florida, Gainesville,

FL 32611

^'''^OUQUETTE , F. M. , Drawer E, TAMU Agri. Res. &
Ext. Center, Overton, TX 75684

MOOSO, G. , Rosepine Res. Sta., P. 0. Box 26,
Rosepine, LA 70659

MOSIJIDIS, J., Dept, of Agronomy & Soils,

RUELKE, 0. C. , Dept, of Agronomy, 2195 McCarty,
University of Florida, Gainesville, FL

32611

Auburn University, Auburn University,

AL 36830

ST. LOUIS, D., P. 0. Box 193, Poplarville, MS
39470

MOUTRAY, J. B., Jr., Agri-Pro, RFD 3, Ames,
lA 50010

SCHANK, S. C. , 2183 McCarty Hall, University
of Florida, Gainesville, FL 32603

MUELLER, J. P., Dept, of Crop Science, Box 7620,
N.C. State University, Raleigh, NC

27695-7620

SGHMIDT, S. P., Animal & Dairy Sci., Auburn
University, Auburn, AL 36849

NELSON, B. D. , Southeast La. Exp. Sta., 530

Cleveland Street, Franklinton, LA 70438

SCHROEDER, J. , Coastal Plain Experiment Station,
Agronomy Dept., P. 0. Box 748, Tifton, GA
31793-0748

"^OCUMPAUGH, W. R. , Star Rt . 2, Box 43C, TAMU

Agri. Res. Station, Beeville, TX 78102

^ SMITH, A. E. , Georgia Expt. Station, Dept, of
Agronomy, Griffin, GA 30212

PEDERSON, G. A., P. 0. Box 5248, Mississippi

State, MS 39762

STANDAERT, J. E. , Dept, of Economics, Box 8109,
N. G. State University, Raleigh, NC
27695-8109

69

STEPHENSON, R. , Rt . 1, Box 62, Ona, FL 33865.

STRINGER, W. C. , Dept, of Agron. & Soils,

Clemson University, Clemson, SC 29631

STUEDEMANN, J. A., Southern Piedmont Conserva-
tion, USDA, ARS, SWCRD, P. 0. Box 555,
Watkinsville, GA 30677

TAYLOR, N. L., Agronomy Dept., N-222F Ag .

Science Bldg.-N, University of Kentucky,
Lexington, KY 40546

TAYLOR, T. H., 1253 Kastle Rd . , Lexington, KY
40503

TEMPLETON, W. C., 800 Brookhill Drive,
Lexington, KY 40502

THOMPSON, W. C., North American Plant Breeders,
121 Dantzler Court, Lexington, KY 40503

THRO, A. M. , Dept, of Agronomy, Louisiana

State University, Baton Rouge, LA 70803

TOLLNER, E. W. , Agric. Eng. Dept., Griffin,

GA 30212

TOPEL, D. G. , Dept. Animal & Dairy Science,
Auburn University, Auburn, AL 36849

UNDERSANDER, D., 6500 Amarillo Blvd., TAMU
Ag. Res. & Ext. Center, Amarillo, TX
79106

WACEK, T., Kalo Agric. Chemicals, Inc.,

P. 0. Box 12567, Columbus, OH 43212

y^ELLS , H. D., Dept, of Plant Pathology,

Georgia Coastal Plain Exp. Sta., P. 0.

Box 748, Tifton, GA 31793-0748

WHITE, H. E. , Coop. Ext. Service, Virginia

Polytechnic Inst., Blacksburg, VA 24061

WILKINSON, S., USDA-ARS, Sou. Piedmont Conser-
vation Res., P. 0. Box 555, Watkinsville,
GA 30677

i/^WINDHAM, W. R. , R. B. Russell Research Ctr.,

P. 0. Box 5677, Athens, GA 30604

WITHERS, F. T. , Jr., Animal Research Center,

P. 0. Box ES , Mississippi State, MS
39762

WOLF, D. D. , Dept, of Agronomy, Virginia
Polytechnic Inst., Blacksburg, VA
24061

WOODWARD, W. T. W. , Dept, of Alfalfa Breeding,
P. 0. Box 85, Johnston, lA 50010

70

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