—

The Effect of the Age of Sire
and Dam on Offspring
in Dairy Cows

C. L. ALLEN

Reprinted without change of paging, from the
Journal of Heredity (Organ of the American
Genelic Association), Vol. XIII, No. 4; Wash-
ington, D. C., April. 1922,

feb Eee ChOF THE-AGE OF SIRE
AND DAM ON THE QUALITY OF
OFFSPRING IN DAIRY COWS

A THESIS

PRESENTED TO THE FACULTY OF THE GRADUATE SCHOOL
OF CORNELL UNIVERSITY IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF

DOCTOR OF PHILOSOPHY

BY
CHARLES LORING ALLEN

hl
|

1920

Reprinted from THE JoURNAL OF HEREDITY (Organ of the American Genetic
Association), Vol. XIII, No. 4; Washington, D. C., April, 1922.

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Reprinted, without change of paging, from the Journal of Heredity (Organ of the American
Genetic Association), Vol. XIII, No. A; Washington, D. C., April, 1922

THE EFFECT OF THE AGE OF
SIRE AND DAM ON THE
QUALITY OF OFFSPRING

IN DAIRY COWS

C.-L. ALLEN

Cornel) University, Ithaca, N. Y.

A FAMOUS HOLSTEIN SIRE
FiGurE 10. Ormsby Korndyke Lad (102469) one of the great sires of the Holstein Friesian
Breed. His daughters are noted for their high production records for both 7 day and yearly work.
He has 18 daughters with records of over 30 pounds of butter (80% fat) in 7 days. He also has
14 daughters with records of over 1000 pounds of butter (80% fat) in one year. The sire of Ormsby
Korndyke Lad was only 23 months of age when he was born and his dam was just a little over 4
years of age (51 months). Photograph from Holstein Friesian World.

HE effect of the age of parents on

the quality of the offspring is ina

large measure concerned with the
idea of cumulative inheritance, par-
ticularly if we do not consider the
matter of the proven sire or dam.
If an animal is a more valuable
parent after it has attained maturity,
it is more valuable for one of two rea-
sons. Either the mature animal must
be able, merely because of its full
physical development better to im-

press its characters on its offspring, or
the mature animal must in the process
of attaining maturity, have become
endowed with something, due to train-
ing or environment, which it can trans-
mit to its progeny. After a century of
study, this matter is far from settled
and the question as to the possible
effect of environment on the transmis-
sion of a tendency to increase or de-
crease certain quantitative functions
is still important.

167

168

The Journal of Heredity

JOHANNA DE KOL CONCORDIA

At three and a half years of age her record was 19037 pounds of milk and 671
Her sire, Sir Clothilde Concordia, was two years nine months of age when
she was born, while her dam, Cold Spring Johanna De Kol 2nd, was three years and a half old.
The great number of cases where the parents of high producing cows are as young, or younger
than these, leaves no doubt that the off-spring of immature parents are just as good producers or

FIGuRE 11.
pounds of butterfat.

transmitters of production as those born when the same parents are mature.

Department of Agriculture. (See text, p. 173.)

In practical breeding, it would be
very advantageous to know definitely
whether the young born of immature
parents are as valuable for production,
and for reproducing their kind, as
those born of more mature parents.
It is the aim of this paper to show
whether the parentage of a group of
high producing or superior cows aver-
ages older than the parentage of a group
of comparatively low producing or
inferior cows. The paper also attempts
to show the percentage distribution of
offspring for the various ages of both
sire and dam; the age when cows
actually make their best records; and
whether the offspring of very young or
very old animals are inferior.

Photo by U. S.

METHOD

The data reported in this paper were
taken from Volume 27 of the Ad-
vanced Registry Year book and the
Herd Books of the Holstein Friesian
Association of America.

The superior class of animals chosen
include those that up to April 30th,
1916, had made records of 24 pounds
or more of butterfat in seven days.
This included all of the so-called
thirty pound cows since 24 pounds of
butterfat is equal to 30 pounds of
eighty percent butter. For purposes
of more careful study, this class was
divided into three groups as follows:

Group I—AIl cows producing over
27.3 pounds of butterfat in 7 days.

Allen: Effect of Parents’ Age on Quality of Dairy Cows

Group II—AIl cows producing be-
tween 25.6 and 27.3 pounds of butter-
fat in 7 days.

Group IIi—AIll cows producing be-
tween 24.0 and 25.6 pounds of butter-
fat in 7 days.

The comparatively inferior class of
animals chosen includes all of the so-
called mature cows, that is, cows five
years of age or over, that produced
less than fourteen pounds of butter-
fat in seven days and were entered in
the 27th Volume of the Holstein Frie-
sian Advanced Registry Year Book as
entries or re-entries. This class was
divided into three groups that were
fairly comparable in numbers to the
groups of the superior class, as follows:

Group I—AIl cows producing be-
tween 12 and 12.5 pounds of butter-
fat in 7 days.

Group II—AIll
between 12.5 and
butterfat in 7 days.

Group III—AIl cows producing be-
tween 13.0 and 14.0 pounds of butter-
fat in 7 days.

The groups were arranged so that
the very highest producers were in
group 1 of the Superior Class and
the very lowest producers were in
group 1 of the Inferior Class. Then,
if there was any difference in age,
it was thought that the first groups
should be further apart than the second
and third groups.

The 7 day record was chosen as the
basis for this study because a larger

cows producing
13.0 pounds of

169

number of records were available and
the 7 day record is generally recog-
nized as a valuable method of deter-
mining the productive ability of dairy
cows.

Three generation pedigrees were
compiled for all the cows of both the
Superior and Inferior Classes. These
pedigrees included the date of birth
for all animals in every pedigree. This
makes it possible to compute the dif-
ference in age between any animal and
its parents and tells us the age of the
parents at the time the animal in
question was born. This also provides
data for determining the average differ-
ence in age between generations, and
allows the calculation of the percentage
distribution of offspring according to
the age of parents, making it possible
to observe whether more good cows
or poor cows are born from very young
or very old dams. The difference in
age between parent and offspring was
computed in months to the nearest
month.

In order to determine at what age
the superior cows made their records,
it was necessary to take this data
directly from the Advanced Registry
Year book and record it on the pedi-
gree.

RESULTS—THE DIFFERENCE IN AGE
COMPARED
Table I gives the average age of the

ancestry of the Superior and the Infer-
ior Classes by groups and for the classes

TABLE I. Average Age, in Months, of Ancestry of Superior and of Inferior Classes of Cows

Inferior Cows

Superior Cows
Ancestor Group 1|Group 2|Group 3
SiLereecsemsc a 44.3 Sil 7 46.3
| DE eva gyetinge, oa cages etd Ih CSc) 4) Wily
Paternal grand sire.|. 48.6 49.6 49.6
Paternal grand dam.| 64.9 65.2 67.6
Maternal grand sire.| 42.3 41.4 42.3 |42
Maternal grand dam| 65.2 63.0 59.6
Great grand sire!...| 44.3 44.8 48.1
Great grand dam!..| 61.3 59.0 63.8
Number of pedigrees
in each group and
Glass yaad: 86 121 404

1 Great grand sire refers to sire of paternal grand sire.

the maternal grand dam.

Class Group 1/Group 2|Group 3 Class

14.647] 45.7 | 44.6 | 41.6 [43.14 .529
.9+.890] 60.0 | 62.2 6457 63-0 2944
.5+.717] 45.4 | 46.4 | 46.7 |46.6+ .646
.7+.929] 66.5 | 69.4 | 65.8 |66.7+1.034
14.507] 44.8 | 43.0 | 43.4 143.6+ .508
SOEE Shop Oo 0 | 6954. 16278) O47 OS
.9+.640] 45.4 | 47.9 | 43.8 |45.1+ .602
poe WOOO) Olen UPA GAN 64.7 |65.7+1.006
611 111 114 285 510

Great grand dam refers to the dam of

170

as a whole. This table allows us to
make comparisons and determine any
significant difference between the aver-
age age of the superior cows and the
(comparatively) inferior cows.

It will be noted in table I that
the greatest difference in age is four
months and that this occurs in the
case of the sires. This difference
might seem to be somewhat significant
in the light of the probable error as a
measure of its probable significance.
The difference is more than three
times the probable error but the prob-
able error in this case is small. We
must remember, however, that four
months is not a very marked difference
and this difference loses a large part of
its significance when we study the
group averages. There is more differ-
ence between the groups within the
classes even here than there is between
the classes themselves. This is still
more noticeable in other places in the
table where the class difference is not
so great. Take for example, the case
of the dams, the great granddams, or
the maternal grand sire. In each of
these cases, the difference is probably
insignificant in the light of the prob-
able error, and in each case, the differ-
ence between the groups within the
class is greater than the difference
between the classes.

The real difference in age between
the various parents and generations is
more clearly shown by means of a
pedigree. Such a pedigree is given in
Figure 12.

It is evident that there can be no
increased hereditary value due to the
age of the dams, for in every case ex-
cept one, the dams of the Inferior Class
average older, though not significantly
so, than the dams of the Superior Class.
In the one case, that of the paternal
granddam, they average exactly alike.

From a study of Table I and the
pedigree, Figure 12, it is apparent
that there is no significant difference
between the ages of parents of the
Inferior and of the Superior Classes.
In only one case is the difference out-
side the limits defined by three times
the probable error. In this case, the

The Journal of Heredity

small difference between the class
averages can hardly be considered sig-
nificant when there is so great a differ-
ence between the group averages within
the class. °

BULLS ARE NO MORE VALUABLE
PARENTS AS THEY GROW OLD

Turning our attention again to the
pedigree, Figure 12, we note that in
every case the Superior sires on the top
line of the pedigree are older than the
corresponding inferior sires. The dif-
ference is probably not significant
even in the case of the sires, but the
tendency persists.

This led to a study to determine
whether a _ bull produced superior
offspring as he grew older. From a
study of four bulls having a total of
five hundred and six daughters, it
seems that bulls may or may not have
better daughters as they grow older,
depending on the quality of animals to
which they are bred. Asa bull proves
his superior worth, he is very likely to
be bred to better cows and produce
better offspring. This probably ac-
counts for the difference shown in the
pedigree. This whole matter will be
fully discussed in a later paper. Thus
the difference in age of sires can be
very readily assigned to the use of the
sires and there is no indication that
the sires are any better when they are
old than when young and immature.
In fact the frequency distribution,
Figures 13 and 14, tends to show that
the young parent of either sex is just as
valuable as a parent when immature
as it is in later life. The frequency
curves include only the sires and dams
of the first generation.

FREQUENCY DISTRIBUTION ACCORD-
ING TO AGE OF SIRE

In the frequency curves, Figures
13 and 14, it will be observed that
the curves run very nearly parallel
throughout. The curves start high,
indicating that a large percentage
of cows in both the Superior and
Inferior Classes are sired by very
young bulls. In this connection, it
will be remembered from Table I that

Allen: Effect of Parents’ Age on Quality of Dairy Cows

49.5
46.0

GrandiSines3-nes0.8e

Grands Damen eee

66.7
60.7

42.1
43.6

iy A
46.9

45.1
Great Grand Sire

GrandsSire= eee

Grands Damen:

61.0
64.7

| Great Grand Dam
62.5
65.7

AN AGE-PEDIGREE OF THE TWO CLASSES OF COWS
FiGurE 12. This shows the average age of the ancestors of the superior cows (Bold-face type),

and of the inferior cows (Italics).
of the forebears of the two classes.

the sires of the Superior Class average
less than four years of age, 46.4 months
to be exact, and that the sires of the
Inferior Class average somewhat
younger. The largest number of off-
spring were born when their sires were
from two and one-half to three years
of age. This means that these bulls
sired a larger percentage of their off-
spring between twenty-two and twenty-
seven months of age than at any
other time.

Table II shows very clearly just
how our purebred sires are used. It
indicates that improvement has been
based on the selection of young sires
rather than on the use of tried sires.

THE PROVEN SIRE

A bull cannot be called a proven sire
until his first crop of heifers come in
milk and can. hardly be so called
until these heifers have milked at
least one year. Thus a bull can hardly

It is evident that there are no significant differences in the age
(See text, p. 169.)

be called a proven sire until he is five
years of age. In general practice, the
percentage of cows sired by unproven
bulls is probably much higher than the
percentage shown for the animals in-
cluded in this study. This means that
even the breeders who are making
records use a tried sire for only a
small percentage of their cows. That
the tried sire is more valuable is indi-
cated by the fact that 21.1 percent of
the Superior cows are daughters of
tried sires, whereas only 15.9 percent
of the Inferior cows are daughters of
bulls of an equal age. This may seem
to conflict with the idea that the bull
when old is not more valuable, but
the paper referred to above shows that
he is not more valuable as a parent. -

FREQUENCY DISTRIBUTION ACCORD-
ING TO AGE OF DAM
The frequency curve for the dams,

Figure 13, is very much more irregular
than the curve for the sires but on the

PERCENTAGE OF YOUNG BORN

172 The Journal of Heredity

_

a
BSL Obeemer ec

meee
- SSS
24 30 36 42 48 54 60 66 72 78 84 390 96 102 108 114 '20 126 132 138 144 150 156 162 168 174 180 186 192 198 204
AGE OF DAMS IN MONTHS

FREQUENCY CURVE FOR DAMS

FiGuRE 13. The percentage of young born by dams of various ages is shown in this chart.
The age of the dams is computed for six-months periods, and the upper age limit of these groups
is shown. That is, all the dams 24 months and under are considered 24 months old, those between
24 and thirty months of age, as 30 months old, etc. It is evident that much the greater number
of oe are born by very young cows, the quality of whose offspring cannot be known. (See text,
p. 1

Allen: Effect of Parents’ Age on Quality of Dairy Cows 173

whole, even here, the
curves run nearly
parallel. There is,
however, a distinctly
larger percentage of
high producers born
of very young dams
than there is of low
producers. Itis hard
to account for this
unless the Superior
Class have received
better care and are
bred younger on the
average than the In-
ferior Class.

It will be noted in
connection with Table
DM that a. slightly.
larger percentage of
the Superior Class
were born from dams
under five years of
age than there were
of the Inferior Class.
In later life, the two
classes are very near-
ly alike and almost
exactly as many of
the Superior Class
were born from dams
over eight years of
age as were born in
the Inferior Class
brome, Gams: of. a
like age. The per-
centage having dams
over twelve years is
exactly alike for both
classes.

VALUE OF OFFSPRING
OF VERY YOUNG
AND VERY OLD

PARENTS

From a study of
the frequency curves
and Tables II and
III, it is evident that
the young born from
very young parents or
from very old parents
are as valuable as
any for productive

SUPERIOR CLASS) =
INFERIOR CLASS

0.0
24 30 36 42 48 54 60 66 72 at 84 90 96 102 108 114 120 126 132 138 144

AGE OF Backes IN MONTHS

FREQUENCY CURVE FOR SIRES

FiGurE 14. The co-ordinates are the same as in the preceding
chart. The same conclusions apply even more strikingly in this
case, as the sires are not used for breeding purposes as long as the
dams. A sire cannot be considered a proven sire until his first
crop of daughters have been in milk at least a year, which means
that he must be five years of age. These figures are for a selected
class of sires and show that even the breeders who are making
records use tried sires for only a small percentage of their cows.
(See text, p. 170.)

174 The Journal of Heredity

WATSON SEGIS PONTIAC HOMESTEAD

FiGurRE 15. She was born when her dam, Watson Segis Pontiac, was just 2 years, 2 days old,
when her sire, Piebe Laura Allie Homestead King, was a senior two-year-old. Her record is
25,360 pounds of milk and 928 pounds of fat. Her mother has a record of 844 pounds of fat, and
she is the daughter of King Segis Pontiac Count, a great breeding sire, who was only a little over
two years old when she was born. Photo by U.S. Department of Agriculture.

The Percentage of Daughters Born on or before a Given Age of Sire, and the Age
of the Sire at the Time the Dams of the Daughters were Bred

TABLE II.

Percentage of Daughters

Age of Sire when Daughters} Age of Sire when the Dams of

were born Daughters were Bred Superior Inferior
30 Months and Under 21 Months and Under PXf as 28.0
36 Months and Under 27 Months and Under 45.3 45.3
60 Months and Under 51 Months and Under 78.9 84.1
Over 60 Months Over 51 Months Mil Ah 15.9

TABLE III. Showing the Percentage of Young Born Before and After a Given Age of Dam

Age of Dam when Daughters Percentage of Superior Percentage of Inferior
were born Daughters Daughters
30sMonthsjandsUndersese.. sess. ti 2 IDS
JOeMonthsrand (Winders oneness ae ZR 2 21.6
60 Months and Under............. Si. 54.9
OversSuvearsen caer aee aie athe tke on 14.8 15.0
Ver eVieanss «Scere ass 2.8 2.8

Allen: Effect of Parents’ Age on Quality of Dairy Cows

TS

A SIRE OF RECORD-MAKING DAUGHTERS

FicureE 16. King Hengeveld Aaggie Fayne (56635) has shown remarkable ability to transmit
production. He was slaughtered when only three years of age and asa result has only 31 A. R. O.

daughters.

Eleven of these daughters have records in excess of 30 pounds of butter (80% fat)

in 7 days. Four of his daughters have yearly records. Three of these records made by two and
three year old heifers average 21,762.2 pounds of milk and 978.93 pounds of butterfat. The other
yearly record was made by a mature daughter and is 15,486.1 pounds of milk and 530.89 pounds

of butterfat.

King Hengeveld Aaggie Fayne was born when his parents were quite young. His sire was
22 months of age and his dam 28 months of age when he was born. Photo by the Holstein-Fresian

World.

purposes. An unusually large percent-
age of the Superior Class were born
before their dams were two and one-
half years of age and must have been
first calves. The sires of a large per-
centage of the Superior Class were also
under two and one-half years when the
dams were bred. On the other hand,
just as large a percentage of the
Superior Class as of the Inferior Class
is from very old parents.

AGE WHEN THE BEST RECORDS ARE
MADE

Table IV was arranged for the Supe-
rior Class only. The best record was
used in every case. If any of the cows
herein considered have made a better
record since the collection of this
data this fact introduces an error.
It is recognized that only a very few
cows have ever made more than one

TABLE IV. The Average Age of All the Superior Cows at the Time Their
Records Were Made

| Group I Group II Group III Superior Class
Number of Cows........ 86 121 404 611
Average Age in Months.. 69.7 Hj Al Teer! UPd!

176

record above thirty pounds of butter
in a week and most of those that
have done so are here considered. This
error, then, is in all probability very
small.

The group averages and the class
average all show that the best records
of the animals herein considered were
made at an average age of about six
years. Of course many were much
older than this and many were younger,
but it is well known that animals vary
greatly in rapidity of development.
It would seem that the numbers con-
sidered are large enough to make the
average significant even though it is
recognized that most cows do not have
a chance to make a record every year.
The cow is most likely to be tested at
the time she shows greatest promise.
Since these high producers made their
best records at six years of age, it
seems only fair to assume that they
were at the height of their productive
capacity at this time. It would also
indicate that cows generally reach the

1 PEARL RAyMonpD, The Change of Milk Flow with Age.

Station Bulletin, No. 262.
2 GOWAN,
Bulletin, No. 293.

1917.

1920.

J. W., Studies in Milk Secretion VIII.

The Journal of Heredity

limit of their possibilities for high
production at about this age. This
contention is supported from other
sources,! although one investigator,”
who attacked the problem”™ in an
entirely different manner, maintains
that the highest production is not
reached until much later in life.

SUMMARY

The parentage of superior or high
producing dairy cows is no older than
the parentage of comparatively inferior
or low producing cows and thus the old
animal is no more valuable as a parent
than the young animal.

As far as the age of either parent is
concerned, the young born at one time
in life seem to be just as valuable as
the young born at any other time.

A very large percentage of our cows
are born of immature parents but the
proven animal at any age is much more
valuable for breeding purposes.

On the average, cows make their
best records at about six years of age.

Maine Agricultural Experiment

Maine Agricultural Expiriment Station

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