-Issued January 18, 1913.

US) DEPARTMENT: OF “AGRICULTURE,
BUREAU OF ANIMAL INDUSTRY.—BULLETIN 156.

A. D, MELVIN, Cuter of Bureau.

THE INFLUENCE OF BREED AND INDIVIDUALITY ON
THE COMPOSITION AND PROPERTIES OF MILK.

BY

UC. HBO R EES,

Protessor of Dairy Husbandry, University of Missourt,
AND

ROSCOE. H. SHAW,
Chemist, Dairy Division, Bureau of Animal Industry.

LS =

Wikis

WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1913.

_ Monograph

dass OF 25 |

ms
Book_-E. 2

Issued January 18, 1913.

U. S. DEPARTMENT OF AGRICULTURE,
‘ BUREAU OF ANIMAL INDUSTRY.—BULLETIN 156.

A. D. MELVIN, Cuter or Bureau.

THE INFLUENCE OF BREED AND INDIVIDUALITY ON
THE COMPOSITION AND PROPERTIES OF MILK.

BY
C. H. ECKLES,
Protessor of Dairy Husbandry, University of Missourt,
AND 3
“ROSCOE H. SHAW,

Chemist, Dairy Division, Bureau of Animal Industry.

WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1913.

BUREAU OF ANIMAL INDUSTRY.

Chief: A. D. Metvin.

Assistant Chief: A. M. Farrinaton.

Chief Clerk: CHARLES C. CARROLL.

Animal Husbandry Division: GEorGE M. RomMet, chief.
Biochemic Division: M. Dorset, chief.

Dairy Division: B. H. Rawt, chief.

Field Inspection Division: R. A. Ramsay, chief.

Meat Inspection Division: Rice P. Sreppom, chief.
Pathological Division: Joun R. MouuEr, chief.
Quarantine Division: RicHarp W. Hickman, chief.
Zoological Division: B. H. Ransom, chief.

Experiment Station: E. C. ScHroepER, superintendent.
Editor: James M. Pickens.

DAIRY DIVISION.

B. H. Raw, Chief.
HELMER RaBILD, in charge of Dairy Farming Investigations.

S. C. THompson, in charge of Dairy Manufacturing Investigations.

L. A. Rocers, in charge of Research Laboratories.

Ernest Ketty, in charge of Market Milk Investigations.

Rosert McApam, in charge of Renovated Butter Inspection.
9

“

DOF D:
IAN 22 1918

LETTER OF TRANSMITTAL.

U. S. DEPARTMENT OF AGRICULTURE,
BuREAU OF ANIMAL JNDUSTRY,
Washington, D. C., July 11, 1912.

Str: I have the honor to transmit, and to recommend for publi-
cation in the bulletin series of this bureau, the accompanying manu-
script entitled ‘‘The Influence of Breed and Individuality on the
Composition and Properties of Milk,” by Messrs. C. H. Eckles, pro-
fessor of dairy husbandry, University of Missouri, and Roscoe H.
Shaw, chemist in the Dairy Division of this bureau.

The experimental work reported herein forms part of a series of
cooperative investigations inaugurated in 1906 between the Dairy
Division and the Missouri Agricultural Experiment Station, with the
object of studying in detail the factors influencing the composition
and properties of milk as produced under normal dairy conditions.
The first results of the work have been forwarded for publication as
Bulletin 155, entitled ‘‘The Influence of the Stage of Lactation upon
the Composition and Properties of Milk.”

Respectfully,
A. D. MEtvin,
Chief of Bureau.
Hon. JAMES WILSON,
Secretary of Agriculture.

Lit SPU OAD RR AME ae j
: Deal} on ‘ vf ny Ska rh a!
7a 7 hk iA ti ee: yy il be Las
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hed wet bits if Avid Te itd iy, ri erie aoliinoiyga ?,

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rad he eit} (eid jd WED SEA dea ht Me nen. Leta ent writ ra

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TInt OF ts tina rs: byt vive saa! Pe apaild Ab “n wih, da able ae

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an aii hy Bolte. atthe ngitnaage wy
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CONTENTS:

Method of sampling and preparation of samples for analysis...................
PRT Ee yLMIeTaVeTALO. Or COU pec e sm: aM es aoe wee ra ER ea te cle
Poem lic stele = POLONIA eres set ote ogre Semis othe hte araja y's oa eo od hotSe
USSU NG Sap abe fa SR ME eg BE ae Ay seh EN ar A

TCE OS dC1¢31 CR ae eRe eh eS een yet ier Sys Cee” Re poy Ree ee ES Oa oe

(OR ys(orh al Sts SA RS CET th get. ORME LAURE SAP a RO a | aa

The chemical and pieyeieal constants a the tats, es eee
Relative size ohthe tat plobules: ..29. 22095. 20. Fo SS Ae ee

Wed veichert-Meisel number... ht a4.805 ae ce sa ee eee ee
(Rheaodin-a bsorphion mem Per re. oe ie 288 oe aioe age Seas ce

The saponification or Koettstorfer number. .......-..............---
Drenmeltme poimtion the dats ~ 2 .-e. to ete eee ets aks oes ois
PumInUHEy came COMEINSIOMB sco rsctees co ee eee cee. Maram Bere eee tee

ILLUSTRATION.

Fic. 1. Relative size of the fat globules in milk of dairy cattle

20

» '
|) or
: } mw y
} ve
-
7 '
aid

b \ a oe a Maadwnies orl to a af
fi ty ea ul A dn whol Quesaportiy fetid ginb iqtial, fay Tab
F i Site wer tM a gered of De
i : 4 SRS Aerie Vit Pee Oe _ eapnoenneneg es voilt Tost
yy 4 ; ~ eA ee eer Ph waa de a wea ia

ae cr) {<9 se

iy , . | Bi isl
He AG iS ; Fiua UA ‘nae eee
ie Ara oh ea esta toad

THE INFLUENCE OF BREED AND INDIVIDUALITY ON THE COM-
POSITION AND PROPERTIES OF MILK.

INTRODUCTION.

In 1906 the Dairy Division of the Bureau of Animal Industry, in
cooperation with the Missouri Agricultural Experiment Station,
began a series of investigations, the main object of which was to
study in detail the factors influencing the composition and proper-
ties of normal milk. It is a well-known fact that although the
same constituents are always present in milk, the relative amount
of each is subject to constant variations. Among the causes of
these variations are known to be the breed of the animal, the stage
of lactation, the individuality, and to some extent the feed, the
interval between the milkings, and the temperature and weather
conditions. It is also known that the first and the last milk drawn
differ in composition.

A large amount of data has been published regarding these varia-
tions, the greater part of which deals with the fat content alone.
In planning this series of investigations it was arranged to give
attention first of all to the variations occurring during the period
of lactation. The data concerning this part of the subject have
been prepared for publication as Bulletin 155 of the Bureau of Ani-
mal Industry, entitled ‘‘The Influence of the Stage of Lactation on
the Composition and Properties of Milk.”’ In carrying on this inves-
tigation the plans were so arranged that the influence of breed and
individuality of the animals could be studied concurrently with that
of the period of lactation, and a presentation of these results is the
object of the present paper.

There is no lack of data concerning the influence of the breed and
the individuality of the animal upon the composition of milk as far
as the per cent of the fat is concerned, although in practically all
investigations reported there was no uniformity in the rations fed
the animals and no data taken concerning the composition of the
fat produced. When the influence of the stage of lactation is not
taken into account, and when the ration is changed from time to
time or varies with different animals, it is clearly impossible to state

54010°—Bull. 156—13——2 7

8 INFLUENCE OF BREED AND INDIVIDUALITY ON MILK.

to what extent any variation found may be due to the ration fed
and to what extent to the stage of lactation, breed, or individuality
of the animal. It is especially important to keep the ration uni-
form, since it has been demonstrated that the nature of the food
has an important influence, more particularly in regard to the com-
position of the fat.

PLAN OF THE INVESTIGATION.

Eleven animals were selected for the investigation, consisting of 3
representatives each of the Jersey, Holstein, and Shorthorn breeds,
and 2 of the Ayrshire breed. These cows were typical specimens
of the breed—that is to say, neither superior nor inferior producers
of milk, but about the average. They were all purebred and reg-
istered. They were kept under much the same conditions as would
be found in a commercial dairy except in regard to the control of
the feed of the animals. The ration fed was of uniform composi-
tion throughout the entire lactation period and was made up as
follows:

Choice ’alfali® hay aic-6 loose eee seas mae oe aekle oe ectok vane DARI
Grain mixture:
Corn, Sipentass..0: Use. cok. DYER. eels eee. de oJ
Bran, dopariaatessee tics a bse = 3 otc tetas ees ee 2 parts.
Oate, 1 partes ts. eso oes Be hg eee ee cls ta ae

This ration supplied the nutrients necessary for milk production in
about the right proportion. The ratio between the hay and the
grain was such that the animals would eat the entire ration at all
times. The amount fed was governed by the needs of the animal.
The animals all went through the entire lactation period with no ill
effects resulting from the lack of variety, and in no case was there
any serious sickness of any kind. The hay, which was the most
variable part of the ration, was bought in large quantities from the
same source in order that there might be few changes in its compo-
sition. The animals were housed at night in the barn for feeding
and milking and in the daytime were turned outside in a dry lot.
The date for beginning the taking of samples was 5 days after the
birth of the calf. The sampling was continued until the production
of milk declined to the point where in a commercial dairy the cow
would not be milked longer. A more detailed account of the plan
of the investigation is found in Bulletin 155, previously mentioned.

METHOD OF SAMPLING AND PREPARATION OF SAMPLES FOR
ANALYSIS.

The milk was weighed immediately after milking and mixed by
pouring from one pail to another. A sample consisting of about 1
liter placed in a glass jar bearing the number of the cow and marked

RESULTS OF THE EXPERIMENTS. 9

with the amount of milk produced was delivered at the laboratory.
A certain number of cubic centimeters per pound of milk produced
was then measured out and placed in a closed receptacle. In this
manner a composite sample was prepared representing the produc-
tion of that particular cow for 1 week. The milk was preserved by
the addition of formalin. At the end of the week the composite
sample was thoroughly mixed and a subsample consisting of about
300 c. c. taken for analysis. The remainder of the composite sam-
ple was heated to the proper temperature and the cream separated
with a hand-power separator. The cream so obtained was churned
by shaking in a glass jar, and the butter resulting was melted on a
steam bath. The methods of sampling and analysis have been
described in detail in Bulletin 155; it is sufficient to say that the
methods of analysis followed were those of the Association of Offi-
cial Agricultural Chemists wherever possible.

THE TRUE AVERAGE PER CENT.

In many cases in reporting analyses of milk a simple average
instead of a true average is given. An average made in this man-
ner is often misleading. In the case of the constituents of the milk
it generally gives a result somewhat high, since milk becomes richer
as it decreases in amount toward the end of the lactation period.
Unless otherwise stated the averages given in this publication rep-
resent true averages. The average per cent of fat for the lactation
period, for example, is found by dividing the total milk into the
total fat produced.

RESULTS OF THE EXPERIMENTS.

Table 1 gives the data concerning the cows used in this investi-
gation. Under the heading ‘‘Period samples were taken” is shown
the periods covered by the samples taken for analysis.

TABLE |.—Data concerning the cows used.

- m4 Av- | To-
0. tal _|erage| tal
Date of Date of . : l

Breed of | Age : ; Period samples were taken. | yield fat ield

ai calving. breeding. of eae abs t

milk.| tent. | fat.

Ys. mo. Lbs. | P.ct.| Lbs.
Jersey .. 4 6 10] Nov. 13, 1906 | Dec. 30,1906 | Nov. 24, 1907, to Sept. 7, 1908...| 5,429] 4. 87/264. 45
Glos 2s 99 8 1j)Jan. 1,1907 | Mar. 23,1907 | Jan. 5, 1907, to Nov. 30, 1907....| 6,115] 4.64/284. 04
S05 222: 118} 11 4| Sept. 27,1906} Not bred....} Oct. 6, 1906, to Oct. 26, 1907.....| 5,733] 5.36|307. 45
Ayrshire. .} 300 3 8] Dec. 28,1907 | Feb. 23,1908; Dec. 29, 1907, to Oct. 3, 1908... .|} 6,275] 3.51/220.34
Bose sce 301 4 8 Sept. 27,1907 | Mar. 16,1908} Sept. 29, 1907, to Sept. 18, 1908..| 6,382] 3. 85/245. 64
Holstein. .| 205) 5 3} July 17,1907] Dec. 1,1907} July 20, 1907, to Aug. 8,1908....] 8,684] 3. 24/280. 76
Ee 206 5 0} May 31,1907 | Sept. 28,1907 | June 1, 1907, to Apr. 4, 1908..... 8,994] 2.93263. 66
Hoos 224 209 3 8] July 20,1907 | Nov. 18,1907 | July 20, 1907, to July 4,1908....| 8,814] 3.02/273.34
Shorthorn} 400 4 4) Sept. 30,1907} Jan. 25,1908} Oct. 5, 1907, to Aug. 1, 1908..... 5,172} 3.89/201.37
Do... 402 4 11} Oct. 13,1907 | Dec. 21,1907 | Oct. 19, 1907, to July 18, 1908...] 4,449] 4.13/183. 57
Oroe 403 6 0} Feb. 11,1908] July 7,1908| Feb.15, 1908, to Dec. 19, 1908...| 6,539] 3.35/220. 52

10 INFLUENCE OF BREED AND INDIVIDUALITY ON MIPK.

TOTAL SOLIDS.

The determinations for total solids were made by-using the Bab-
cock asbestos method. The figures given are in each case an average
of the determinations for 4 weekly composite samples. These ere
simple averages. The averages given for the lactation period of the
animal and for the breeds are true averages.

Table 2 gives the percentage of total solids for each of the 11 ani-
mals used in the investigation by 4-week periods, the average for
each animal for the period of lactation, and the average by breeds.
The results correspond closely with those usually given for the breeds
included. In Table 3 is given a compilation of analyses reported by
several experiment stations in this country. The figures used
include only those that represent purebred animals of the respective
breeds, and where an entire period of lactation is involved. The
data included in the column headed ‘‘Other American experiment
stations”? include all in print coming under the above conditions.
A portion of this data was taken presumably by calculation from the
specific gravity and the fat. Since these animals, owned by various
experiment stations, represent a variety of conditions, it is believed
that the average figure given, which includes all the data of such
kind available up to the present, is reasonably accurate.

Table 4 gives the composition of the total solids in percentage of
fat, protein, and sugar. The ash is not included, since it was lacking
in some of the data, and furthermore, the amount of ash is so uniform
with the different breeds and different individuals that no marked
variations were found. The animals supplying the data from the
New Jersey and New York experiment stations are the same as in
Table 3.

TABLE 2.—Average percentage of total solids for each cow, and breed average, by 4-week

periods.
Jerseys. Ayrshires.
Four-week period No. Average Average
No. 4. No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires.
|
| Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent.
LO. 2 I ee Pee eck oes Lar slemeedcetete| ses sce cece 14.13 13.07 13. 20 13.13
Bi be oe eect ae Bea one Garner ate 13.09 14.08 13.58 12. 27 12.50 12.39
Src see ce dee wens die cece deere lec coe aentne 13.30 14.55 13. 92 12.14 12.57 12. 36
ABA: 5 SOE AT ah Nee ke 14.14 LSM bal bee ce cctniee 13. 64 11.81 12. 64 12. 23
Seite ee Be Re A ee 14. 28 MOFOQHIMRS Sate ee 13. 60 11. 66 13.09 12. 38
GR. 8 2. hes. Peete 14.15 12. 76 15. 30 14.07 11.35 12.86 12.11
Withee 28) = kd cdc eters 13. 87 13. 04 15.16 14. 02 11.38 12.63 12.01
SRD. AE Gere oto ciate ete 13.77 12. 81 15. 61 14. 06 12.15 12. 64 12.39
9 FAR Lee oe. OE Ae 13. 63 13. 35 14.79 13. 76 12. 56 12. 49 12. 52
10 ASRS Sec Se 2s 14. 57 14. 27 14. 45 14. 43 13.85 11.78 12.81
U)) ASSO LS. EOS. 2.00 BOeeae alee tera 15.15 14. 42 Ue bea 13.55 13.55
12 Ae. PA). oes See 16.08 15. 08 T5F 5S) | cee eck 13.04 13. 04
VS eer ee Boe oS fale ieee ea arcte A CGO cee CR ere ae 16.10 UGEIO? et oc ew 13. 27 13. 27
U4 ta! Bis oe Ae Se a i EE Sr el 17.16 VLG sea eios chee nls awet ees

True average of total solids. 14 09 13. 34 15. 02 14.09 | 12. 08 | 12.71 12, 41

RESULTS OF THE EXPERIMENTS. La

TABLE 2.—Average percentage of total solids for each cow, and breed average, by 4-week
pertods—Continued.

Holsteins. Shorthorns.
Four-week period No. Average Average
No. 205.| No. 206.) No. 209. for No. 400.| No. 402.) No. 403.| for Short-
Holsteins. A horns.

Per ct. | Perct. | Per ct. | Per cent. | Perct. | Perct. | Perct. | Per cent.

11.74 10.95 11.24 11.31 13.71 13.74 12.85 13.43

11.58 10.10 10. 23 10. 64 13.29} 13.29 12.16 12.91

11.70 10.18 10. 63 10. 84 13.05 13.07 11.75 12. 62

11.95 10. 27 11.07 11.10 12. 48 13. 07 11.56 UPAaY(

12.11 10. 54 UST 11. 27 13. 06 13.16 11.56 12.59

11.77 10. 73 10. 96 A 15 13.05 12.97 11.65 13. 56

11.98 10. 75 11. 20 11.31 12. 96 13. 02 12.77 12.92

12.16 10.80} 11.23 11.39 13. 08 12. 93 12.52 12.84

11.95 11.01 11.58 11.51 13. 03 13. 81 12. 38 13.07

12.12 11.90 12. 58 12. 20 12. 48 13.94 12.90 13.09

12. 20 13. 30 12. 99 12.83 PONSA et 13.19 13.02

ADO Nhe ceateale 1se5i VENOUS Breehec eral eicer te terh ste ee esta eres eee

LNA ee eas 14.52 ILS Wyden tena ieee | (EPS aL Oana | aa oy er

LIS Fey 3 ean es 11S 3 7 | sees | negra eae PISS OEE Ol SE SESER etic

True average of totalsolids.| 12.12 | 10.73 | 11.35 11883: 08) IF 91301 127 12. 69

TABLE 3.—Comparison of total solids in this investigation with results reported by
American experiment stations.

This investiga- New Jersey Ex- | New York Ex- | Other American

ion periment Sta- periment Sta- experiment sta- | General average.
. tion.! tion. tions.
Breed.
Nu Average Nees Average Nam Average aan Average sam Average
aril total sah total nat total a total P total
E : z : E ni- s ani- :
tani solids. ani solids. mate solids. minis solids. male solids
Per cent. Per cent. Per cent. Per cent. Per cent.
Jerseys. ... 3 14.09 3 14. 34 3 15": 29 14.90 38 14.70
Guermiseys.|52 se. hoes eee 3 14. 48 2 14.8 6 14. 20 11 14. 49
Ayrshire . . 2 12. 41 3 12. 70 4 12.8 17 12.98 26 PLP
Holstein .. 3 11.38 3 12.12 2 12.2 9 12. 29 17 12.00
Shorthorns 3 12.69 3 DEAD | Segoe sell Screcrete oeatatel | era rateestecacs | erences eteare aie 6 12.57

1 Neilson, James. Experiments with different breeds of dairy cows. New Jersey Agricultural Experi-
ment Station, Bulletin 77. New Brunswick, Dec., 1890.
Ae N ew York Agricultural Experiment Station, Tenth, Eleventh, and Twelfth Annual Reports. Geneva,
1891, 1892, 1893.

TABLE 4.—Average composition of the total solids in milk of dairy cattle, as reported by
American experiment stations.

Fat. Protein. Sugar.

New | new | Mis- | Aver-| N°W | New | Mis- | Aver-| NeW | New | Mis- | Aver-

York.| souri.| age. “a York.| souri.} age. York.}souri.} age.

Breed.

SA ECE |W Ole ena CleHl ok Cle | sos Cea lian Chall ea Cballebe a Che) ee Cte
34.9 | 27.6 | 25.4 | 25.8 | 26.3 | 33.8 | 33.4] 34.5! 33.9
B49 EZ T Ae DA Tae DOO Bose) |oos Olan sees 34.2
28.7 | 27.4 | 26.3 | 26.1 | 26.6 | 38.1 | 40.8 | 39.6 | 39.5
28.1 | 27.1 | 27.4) 28.1 | 27.5 | 38.7 | 39.1 | 37.3 | 38.4
Py 745), 83a eerie 26.6 | 26.4 | 38.6 |...-.- 39.3 | 38.9

The fat represents from 28 to 35 per cent of the total solids, varying
especially with the breed and to some extent with the individual.
The total solids produced by the Jersey and Guernsey breeds contain,

<a
12 INFLUENCE OF BREED AND INDIVIDUALITY ON MILK.

on an average, 34.9 per cent of fat, which is relatively high as com-
pared with the Holstein, Ayrshire, or Shorthorn breeds. Among the
breeds included in these data the Holstein, with an average of 28.1
per cent, has the lowest proportion of fat, while the Shorthorn ranks
next. The rule is that those animals having a higher per cent of fat
in the milk also have a relatively larger proportion of fat in the solids.
The individual animals show some variations, but on the whole they
follow the characteristics of their breed quite closely. The per cent
of fat in the total solids produced by the 3 Jerseys used in this inves-
tigation varied from 34.6 to 35.7, the 3 Holsteins from 26.7 to 27.3,
while the 3 Shorthorns varied from 27.7 to 31.7. The individual
variation has to be taken into account in connection with the total
solids, but is of less importance than is the variation due to breed.

FAT.

Table 5 gives the percentage of fat in the milk of the 11 animals
represented in the investigation, expressed in the same manner as
the total solids. The well-known facts regarding the relative compo-
sition of the milk for the 4 breeds used is brought out in these data.

Table 6 gives the average percentage of fat in the milk of animals
used in investigations at the New Jersey and New York experiment
stations; also a compilation showing the average per cent of fat for
all registered animals of the respective breeds, the records of which
have been published by American experiment stations. This table
includes only data relating to purebred animals and where it is possi-
ble to obtain a true average per cent of fat for the entire period of
lactation. It is believed that the summary, representing as it does a
large number of animals in different States under somewhat compar-
able conditions, gives a reliable average as to the fat content of the
milk of the breeds represented.

TABLE 5.—Average percentage of fat for each cow, and breed average, by 4-week periods.

i}
|

Jerseys. Ayrshires.
|
Four-week period No. Average Average
No. 4. | No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires.

Per cent. | Per cent. | Per cent. | Per cent. | Per cent.| Per cent. | Per cent
my, Pe 3. 87 3

Ca

IE Ay ELS A) a aes ee) (ioe eee’ Ss 5. 20 4.01 97
RE CRED se SES AIK Abe $e 4. 63 4.79 5.31 4.91 3.61 3.74 3. 68
Sa Oe Se ee a es Seedy 5.07 4. 43 5.55 5.02 3. 38 3.81 3. 60
el ies RE ew Ce ES ot Ms 4. 85 4. 40 5.11 4.79 3. 36 3.81 3. 59
Shad Foie eee dae ee 4.81 4.33 5.51 4. 88 3.32 4. 08 3.70
Pee oe ae Bt 5.00 4, 22 5.71 4. 98 3. 26 3.78 3.52
Ted. SMR ide! hed Goat 4.73 4. 36 5. 69 4. 98 3.30 3.95 3. 63
Seiie <a de. Sod ee 4.51 4. 18 5. 4.83 3.53 3.94 3.74
[RINT SORA OL Pee 4.73 4. 63 5.17 4. 84 3.74 3.67 3.71
+ RIS aE Ra aa ea 5.18 4. 98 4.47 4. 88 4.52 3.58 4.05
Deseret ae 5. 62 4.83 i Ml ae i te 4.92 4.92
[LIS Ce acted © OME FE WL PF IS 6.07 5. 28 PCa Se ae 3. 96 3. 96
TEN el OG Ee ee a 5.48 Bae, Sees 4.18 4.18
YEE EOE NM AINIRGN | Fae ATE | Ac 6.47 G47 |e. acne gee ee pee

5.36 4.95 3.51 3.85 3. 68

True average of total fat.. 4. 87 4. 64

RESULTS OF THE EXPERIMENTS. 13

TABLE 5.—Average percentage of fat for each cow, and breed average, by 4-week periods—

Continued.
Holsteins. Shorthorns.
Tour-week period No. Average Average
No. 205.)No. 206.) No. 209. for No. 400.) No. 402.) No. 403.| for Short-
| Holsteins. horns.
Pech. | Pact, |) 2. ct. | eer cent. | Pact. |) Poet. |) Pct. | Percent.
Pec Sects: coca dssse PEGE Es efee 3. 24 3.07 3.12 3.14 4.12 4. 55 3.58 4. 08
ee ea cttac \cetclnaislcisieie's 3.14 2.88 2.60 2. 87 4.09 4.17 3.38 3. 88
UPeER RES t carehi-k ss deb teas saaee 3. 02 2. 58 2.74 2. 78 3.99 3.97 3.18 BAG:
ce 5 ee Sie eh ee ae eee 3.20 2. 84 3. 24 3.11 3. 65 3. 80 3.16 3. 54
ONEIEEE 2 SSR Cpa ae. SSR. a eahd 3. 29 2.89 3.14 3.11 3. 70 3. 84 3.14 3. 56
Geeks soo isis sascsews occa w'dea'siste 3.06 3. 06 2.81 2.96 3. 69 3. 92 3.13 3. 58
MAE eae eae eed setiseee ds ee telhe 3. 26 2.88 2.94 3. 03 3.85 3.98 3. 23 3. 69
Ra Sigs er ta era ewe he ea Ls aise 3. 25 3.00 3.01 3.09 8) OB: 3.90 3.55 3.73
QPEECK LY Heads: SIS. ERS. cath oe 3.15 3.00 3.01 3.05 4.05 4. 67 3. 85 4.19
IG OS RUSS 2 ee eee One ee a.0L 3.09 3.52 oon 4.16 4. 42 4.00 4.19
TS ee reason ESE: nih ads 3.31 3.40 3. 46 3.39 4.17 ae 4.05 4.11
i ae 5 3.90 3.697265 HAGE Spa joe See sa
‘ _ 5. 28 4 ABM eee cd aoahesclescecncis| toeeecseas
Peer alle ane S631 le- ye eons
True average of total fat... 3.10 3.09 3.89 4.13 3.37 3.73

TABLE 6.—Average percentage of fat in milk of dairy cattle, as reported by American
experiment stations.

f A All American ex-
New Jersey. New York. Missouri. periment stations.
Breed. |
Suushee Average post het Average Number Average aoe Average
animals. fat. animals. fat. animals. fat. animals. fat.
Per cent. Per cent. Per cent. Per cent.
Perse yrees 5 --<-- oc ss 3 4.78 3 5.60 3 4°95 153 5.14
Guettisey ... .....,<-6 3 5.02 2 ea MD Reto lea |lnee cere stores 21 4.98
ANTSHITO i234: 5-60 cae 3 3.68 4 3.57 2 3. 68 24 3.85
Hosters nt tt 3 3201 2 3. 28 3 3.09 83 3.45
Shiorthom. - . <2: =<. 3 ETS Sees Face ee ee ae 3 3.73 40 3. 63
aula Sees SR lll eels 5 | bane SS Nay fe | eS me ins | eet hah | tect parm | raga 9 4.03

It is a well-known fact that individuals within a breed vary consid-
erably in the percentage of fat. The data here given are too limited
to contribute much of value on this point. While by far the greater
number of individuals within the breed will come close to the average
for that breed, a comparatively few vary widely. It is characteristic
of the breeds having the higher percentage of fat to show the greater
individual variations. The percentage of fat secured during a lacta-
tion period may also be influenced to some extent by the time of the
year in which the milking period began.'’ On the average the milk
produced during the fall and early winter has a higher percentage of
fat than that produced by the same animal in the early spring and
summer. For this reason the cow that is fresh in the fall and pro-
duces the largest quantity of milk during the cool weather will have
a higher average test for the year than will be the case if she freshens
in the spring and produces the maximum yield during the period of
warm weather.

1 Eckles, C. H. Jahreszeitliche Schwankungen des prozentischen Fettgehaltes in Kuhmilk. Milch-
wirtschaftliches Zentralblatt, vol. 5, no. 11, p. 488-502. Leipzig, Nov. 1909.

14 INFLUENCE OF BREED AND INDIVIDUALITY ON MIPK.

TOTAL PROTEIN.

Table 7 gives the percentage of total nitrogen as protein for each
individual and the average for each breed. The totals are also cal-
culated as protein by using the factor 6.38. The results show a
decided influence due to the breed of the animals, the Jersey having
a uniformly higher percentage of protein than the others. The Hol-
steins are the lowest, while the Shorthorns and Ayrshires range
between the Holsteins and Jerseys. The marked influence exerted
by the stage of lactation upon the proportion of this constitutent
present can be seen from the data given and has been shown in a
previous publication.’

Table 8 is a compilation from the same sources as used in previous
tables showing the average percentage of protein in the milk of 5
breeds. It will be noted that the figures obtained at the Missouri
Experiment Station for Holsteins, Jerseys, and Ayrshires are some-
what lower than those obtained at the New Jersey and New York
stations, while the figure for the Shorthorns is slighfly above. There
is some variation with the individuals regarding the amount of this
constituent secreted, as is the case with other constituents of the
milk. The individuals and breeds having the higher percentage of
fat have at the same time the higher percentage of protein. The
same animals also have a higher ratio of fat to protein. With the
11 cows used in our investigation, for each pound of protein there
was found in the milk of the Jerseys 1.36 pounds of fat, in the Ayr-
shires 1.13, in the Shorthorns 1.10, and in the Holsteins 1.05. While
an individual or a breed that produces milk with a high percentage
of fat is certain to have a high percentage of protein as well, the pro-
tein and the fat do not increase in the same proportion.

TaBLE 7.—Average total nitrogen for each cow, and breed average, by 4-week periods, and
average total nitrogen and protein for the whole lactation period.

Jerseys. Ayrshires.
Four-week period No. Average Average
No. 4. No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires.

Lewd codes! si deaceecscdae sectee eek wOuoal es BOSOM mein sen cee 52
Zee oes Mio faoeenAgee ae -53 -51 0.51 202 -47 - 50 - 48
Sean sich Men ase sees 57 51 - 56 55 48 48 48
ASSAM S.A IN. Oo eee ee ESP wed 61 49 54 ~55 47 -51 49
Be tombe aot chertar ie Stree aes 60 49 65 58 46 51 49
Ghte See eee coe eee 59 49 65 .58 47 53 50
Ufo wie ath la ais osiegtlars Ose winata clare LR 59 48 67 -58 46 ol 49
Sererarele ote ccc ie codec ee eee 57 50 64 -57 49 -50 50
Qe Beltesb Chie th ogee Peep ee ae 62 52 64 .59 57 .53 55
SU epart A Sea ae Sie, se. Ae ps Ane AS ss 3. 66 56 64 -62 67 -53 60
1isce As. Ree teh Res ee ee ee 62 65 BOS te Leek cee . 53 53
Leitcises so tape anodes Gant cot ole anes cae 66 70 HOS Sade motes 57 a
VS cies 25 xa Less & hh. cee eS S. See ee eae 75 ni ty | Pee 65 6:
1 A See Ss = ae A ec, gn) (ey |e te aa 57a | Bry (a) Peers (sees ale awe on
True average of total
Mitropen’..2! seeker eee - 58 -OL - 62 57 .49 .52 ool
True average of total
LOIN. cose ooh seen eee 3.70 Bae 3.97 3.64 3. 11 3.33 3.25

1 Bulletin 155, Bureau of Animal Industry, U. 8S. Department of Agriculture. Washington, 1912.

RESULTS OF THE EXPERIMENTS. 15

TABLE a Ns total nitrogen for each cow, and breed average, by 4-week periods, and
average total nitrogen and protein for the whole lactation pervod—Continued.

Holsteins. Shorthorns.
Four-week period No. Average Averaget
No. 205.|No. 206.|No. 209. for No. 400.) No. 402.) No. 403.) for Shotr-
Holsteins. horns.

JERR Ie Teds (53 LEAK G 1 FERNS JER (Aah Sern Cais NIM ER (Oe Raith.

0.49 0. 44 0. 50 0. 48 0. 54 0. 53 0. 52 0. 53

43 38 -45 42 51 .52 «49 51

44 37 ~45 42 - 46 51 47 48

44 39 47 43 48 54 47 50

45 42 45 44 53 55 49 52

45 42 46 44 54 55 51 53

45 41 50 -45 56 55 53 55

44 43 49 45 56 57 57 57

48 44 -52 - 48 58 63 58 59

48 51 - 60 .53 60 70 60 63

61 71 65 -62 Ct eeeeeeee 64 61

Ft hes eee BS RY eh NR a OE fs 5

bit Boecaeee aii Bi Eee oel ectc tes Peeen| eerie =

Gs Sere SN PRS = Tal Loe |e eee Pen Fl Ga aa ="
True average of total

MIFOPON a. eae asciccasae -47 42 -50 - 46 53 55 -51 -53
True average of total

PION. esac omicimas.s 3.00 2.70 3.21 2.93 3.40 3.49 |. 3.28 3.38

TABLE 8.—Average percentage of total protein in milk of dairy cattle, as reported by
American experiment stations.

New Jersey. New York. Missouri. Average.
Breed. |

Nur Average Muuiber Average Meu ber Average Nome Average

animals. | PPotei. | animals. | PPO%M- | animals. | PFo%e!2- | animals. protein,

Per cent. Per cent. Per cent. Per cent.
Jersey.=2.2) fete =- 3-0 3 3.96 3 3.81 3 3.64 9 3.80
Guermsey .i25--..<2-% 3 3.92 2 Shafi ee eee a ees Se 5 3. 84
Asyrshire 2/22 -2. 23.5 3 3. 48 4 3. 29 2 3.25 9 3.34
Holstein. of eae. =... 3 3. 28 2 3.23 3 2.93 8 3.15
Shorthornsnec2-6 = 3 SP Reece, sted erence ae 3 3.38 6 3.32

CASEIN.

Table 9 gives the average percentage of protein in the form of
casein for each individual and for each breed. Much the same range
of variation is found here as is the case with the total protein. The
percentage of the total protein present as casein ‘was for the Holstein
milk 80.4, the Jersey 80.7, the Ayrshire 83, and the Shorthorn 83.5.
No special breed characteristics can be observed in regard to the
relation of casein to the total protein. The individual variation is
of some importance, but not so very much.

16

INFLUENCE OF BREED AND INDIVIDUALITY ON MIDK.

TABLE 9.—Average casein nitrogen for each cow, and breed average, by 4-week periods,
and average casein nitrogen and casein for the whole lactation period.

Jerseys. Ayrshires.
Four-week period No. verag Average
No. 4 No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys shires
Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent.
1 Oe Se ees foes Seo 0. 44 bia I Se rs 0.43 0. 44 0. 56 0. 50
De os a Sak dies sia dR eee c aoe -38 41 32 son - 40 -50 45
Bee ees cee DO ae see oe ae -48 - 40 48 «45 -40 -48 44
Bo oe eee 5 cas Sd See .49 -40 42 44 38 Alii 45
Ls eee el Nmap see 8 2 -48 -40 54 -47 39 “Fil ~45
ORs cece Seu Nos es ae oe ee 48 40 .52 47 .39 553 46
Toe NR SR oe eee 47 .39 54 47 39 sea 45
Se Ue or ee 46 - 40 04 47 44 -50 47
Qe EE ne a Ee eee ee ea 50 -42 SOL 48 .52 -53 -53
TO bec 2 se Lee asc d eet co ate! 2, -46 50 -49 -59 - 53 - 56
1) eR a RS A or ine is Se ae ~oL 51 SOLS aeecemone bo 53
1 ee ee ee Cera tLe (eee SY 53 <5 MAAN TS oe zo etal 1
BB se cats Sere ke crete ee ee Serer ee [os | ee 61 ROLY er eetwecee 65 65
DAS eee eR eis See a A hea el | eee -58 ROSH Se eee eae sce beta ce cle meemeee
True average of casein
MItOPen.24- Fees tee - 46 -42 .49 -46 41 -44 -42
True average of casein... . 2.93 2.65 3.13 2. 93 2.62 2.81 2.70
Holsteins. Shorthorns.
Four-week period No. Average Average
No. 205.| No. 206.|No. 209. for No. 400.|No. 402.|No. 403.| for Short-
Holsteins. horns.
Per ct. Per ci.s|2her.ct.\| Penicts_.| Perict..| Per ct. |) Perici. | “Peres.
[ibe 2 cet See ates cere 0.40 0.34 0.39 0.38 0.45 0. 44 0. 42 0. 44
DOGRRE Bo. F se eo). Ga mere 6G -30 34 33 41 -43 38 41
SeE OWES. Seas ween & eeeteee 34 29 34 .32 .38 42 -36 .39
ETRE SL SAT AA ale bee es ht | .36 .30 .36 34 .38 44 37 39
Sap erewoteneinte te cet cco eceee eee AB ARP 35 35 .44 45 -37 42
Ge mean aoc eA eee cle wow eare Sete .38 -oo .36 36 44 . 44 - 43 44
CIS ee SA ae ARE 3 he .37 Jail .39 36 ~45 45 - 46 «45
SES ccc hence esc aeetome san 33 - 40 3d 46 45 -47 46
OB ota 2 oe mess aeeee .38 .36 Al .38 45 .53 - 46 48
Pe os. ale oe ne ects ne cctaoBters cane .39 -42 .49 43 -48 - 56 45 -49
DR SoS Se et CS, Lope SLE 43 .58 .53 SOL OO) [exe cces -48 -d1
1 D2 ph Pe AME ae So Set BABY | Sareea . 59 5) PS eee erat omer SBE he os rn -
Dg secarsilecits cca nck ee ee eee mln |e Getoees .58 By eee heer he hey. mel Moraes 8S
1 ee Oe eee ae a Ot SON semen hernlesiee ne COU Gace cee Secon: eee e es eee eae
True average of casein
MItLOZeN ech eee ee eeoe .39 B88) .39 .37 -43 -45 41 . 43
True average of casein.... - 2.49 2.11 2.49 2.36 2.74 2. 87 2. 62 2.74

RELATION OF THE CASEIN TO THE FAT.

The relation between the fat and the casein is of considerable
interest on account of the possibility it affords of calculating the
casein content from the fat analyses and its relation to methods of
paying for milk of varying quality to be used for cheese making.
Van Slyke! formulated a rule for estimating the casein, limited in
its application to milk with fat contents between 3 and 4.5 per cent.
Shuttleworth ? showed that considerable variations occur with indi-

vidual cows regarding the relation of fat to casein.
1Van Slyke, Lucius L. Modern methods of testing milk and milk products. New York, 1907. See
p. 192.
2 Ontario Agricultural College and Experimental Farm, Twenty-first Annual Report (1895), pp. 19-27.
Toronto, 1896.

RESULTS OF THE EXPERIMENTS. 1%

Hart ' studied the relation between the fat and the casein in the
milk of 26 cows representing 5 breeds and covering 12 days’ time.
He finds that “‘the relation of casein to fat varies among animals of
different breeds and among animals of the same breed.”’ His data
averaged by breeds are as follows:

Relation

Breed. of fat and
casein.

A () nse yy Rk See ais Sa oS ey ea lays sal
@ubernseppacy sy ectathe PARSE cto eee 1.90:1
EFOISCGINE eee se eee emer eee 1.49:1
Avrshine he fet. ses deeb ods) 43 4 1.44:1

The following gives the relation of the fat to the casein in the milk
of each of the 11 cows used in our investigation:

Ratio of

Breed. No. fat to

casein.

VOISGY 2 2 cece ccna. coon eee eeice 4 1.66:1
1,0) spe Ree eee eee aan aoa 99 Aas L

20308 ie eee ee ee er 118 Heal Sal
Average for Jerseys.... -- 1.69:1
Apeshirasnce-cceacct secs oats 300 P20 Fu
(Bre sclipedl Gta 8 beara ined s bet 301 1.47:1
Average for Ayrshires....|...--- 1.36:1

ET OIstaites 7 eee ee eter 205 1.30:1
E+ eee Pee Os a el ee 206 38s

LUT Rao St Sy Sane RIS LSE 209 APA Al
Average for Holsteins. ...|...-.. WesHl gal
BHGEMOMNE os sect =~ a<ceeeeees 400 bain sal
1D (el Sapa ere 2 eee 402 1.44:1

dD js [ae agama 3 trond T a dee, Bev tate 403 1.29:1
Average for Shorthorns...|. ..--- 1.36:1

The above statement, representing as it does in each case the
entire lactation period of the animal fed a uniform ration, gives a
fair basis from which to study this question. The figures show that
there is a variation in the ratio between the fat and the casein that is
dependent upon breed. There is little difference between the
Holstein, Ayrshire, and Shorthorn breeds, but the Jersey shows a
much wider ratio than the others. A study of the figures for
the individual animals shows a reasonably close agreement within
the breed. The conclusion from our data would be that while there
is some variation with the individual the variation due to breed is of
greater importance, and that the breeds that have the highest per-
centage of fat have the widest ratio between the fat and the casein.

1 Hart, E. B. Variations in the amount of casein in cow’s milk. Journal of the American Chemical
Society, vol. 30, No. 2, pp. 281-285. Easton, Pa., Feb., 1908.

18 INFLUENCE OF BREED AND INDIVIDUALITY ON MIPK.

SUGAR.

The sugar content was determined by the optical method.!' The
results are found in Table 10. This table shows that the percentage
of sugar in the milk of the Jersey, Ayrshire, and Shorthorn breeds was
practically the same, while that in the Holstein was somewhat lower.

Table 11 gives the average percentage of sugar from the same
sources as previously used. The average figures show that the
Holstein breed has a somewhat lower percentage of sugar than the
other breeds, although the variation is small as compared with that
of other constituents. It is a well-established fact that, with the
exception of the ash, sugar is the least subject to variations of the
milk constituents. Some variation, however, is found with the
individuals. This is especially noticeable with the Holsteins, where
one has an average of 5.05 per cent and another 4.25 per cent. The
sugar composes from 34 to 39 per cent of the total solids, varying in
this respect with the breed.

TABLE 10.—Average percentage of sugar for each cow, and breed average, by 4-week periods.

Jerseys. | Ayrshires.
Four-week period No. Average | Average
No. 4. No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. | shires.
| Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent.
Sea nen ee sek eee eS eee 4.89 As Oda ES: E525 4.92 5.14 5.17 5.16
Sete cere eee Ie o 4.99 5.15 4.47 4. 87 4.81 4.72 4.77
Dias oie eee o sec ost panera | 4.87 5.17 4.70 4.91 4.64 5.62 5.13
Ae Se Fe cts ocs Oak Se 5. 28 5.06 4.56 4.97 4. 87 5.16 5. 02
ek aula oe SS RSS) Lt Ce pene 5.12 5.04 4.83 4.99 4.96 4.77 4. 87
Gee Ee oan cls cache. eee ere 5.00 4.50 5.21 4.90 4. 57 4. 43 4.50
Mania Se Ses Ode Maw S05 cee eee oe 4.39 4.52 5.20 4.70 4.82 5.38 5.10
Beat See as ee eee eee 4.45 5.14 5.40 4.99 5.08 5.13 5s
OER s oe oe 5 oe 4. 67 4.62 4.57 4.62 5.13 4.85 4.99
TORE Sete tee neces oe eee 4.60 5. 03 4.73 4.79 4.39 4.88 4. 64
DS Oe Selene eee! Sere eee ae eee 5.02 20001) oie 4. Obi eee es ace 4.89 4.89
Le utsiaxce ee Aeee eestcd aoe eae J----2----- 5. 61 4.7 Lie ly (a Peles SS ee 5.04 5. 04
TB eos We he Le Dee Se RE ee ees NC Cea 4.46 CMe (Gh RS ae ee 5.13 5.13
Me lel ee Se tara Pre ay fa ES FS eee es Ae Boe Bee ls pectic a-'s tome n cece] Sone
True total average. ....... 4.85 4.95 4.80 4. 87 4.85 4.96 4.90
Holsteins. Shorthorns.
Four-week period No. Average Average
No. 205.) No. 206.) No. 209. for No. 400. No. 402. No. 403.| for Short-
Holsteins. horns.
Per ct. | Pérck)|Perict. ||| wPenet;.\Pericts |) Per-ct. | Pench
4.69 4.07 4.40 4.39 5.40 4.77 5. 21
4.98 4.49 4.00 4.49 5. 06 5.32 5. 22
4.84 4.44 4.17 4.48 5. 44 5.09 5.39
5.18 4.12 3.95 4.42 5.13 4.72 5.00
5. 42 4. 26 4.42 4.70 4. 87 4.55 4.58
5.37 4.04 4.36 4. 4.95 5.09 5.16
5. 20 4.74 4.16 4.70 5.05 5. 29 4.98
4.76 4.25 3.94 4.32 5.19 4.73 5.11
5.10 4.09 4. 43 4.54 4.65 4.61 4.08
5.12 3.94 4.62 4.56 4. 22 4.31 | 4.17
5.13 4.50 4.79 4. 4,25}.
FLY.) |e ee 4.15 4
ALSOE SLE: 4.30 4
Pi) IN| (OEE a it Pees ee 4
5.05 4.26 4.25 4.5

1 Official and provisional methods of analysis. U.S. Department of Agriculture, Bureau of Chemistry,
Bulletin 107 (revised). Washington, 1908. See p. 118.

RESULTS OF THE EXPERIMENTS. 19

TABLE 11.—Average percentage of sugar in milk of dairy cattle, as reported by American
expervment stations.

New Jersey. New York. Missouri. Average.

Breed. | as ae
N up eth | Average Number | Average Nuiaber Average Number Average
animals. | SU8°%- | animals. | SUS®!- | animals. | sugar. | animals. | SU82!-
Per cent. Per cent. Per cent. Per cent.
VOISOV ee acai Snes 3 4.85 3 5. 41 3 4. 87 9 5. 04
(TFUBRNSOYs oS 5. ck: 3 4.80 2 EO ee esterteretal| Se ciccanee ep 5) 4.98
ALyMSRITGy < 2./2n:'5 <2 3 4.84 4 5.33 2 4.90 9 5.02
PVOISHeIEe fee ce 3 4.69 2 5.02 3 4.25 6 4.65
Shotthorm: 2). £2). 2.2 3 ZS Oe eae oe |S ee ee ey 3 4.99 6 4.89

THE CHEMICAL AND PHYSICAL CONSTANTS OF THE FAT.

While the previously published data regarding the constituents of
milk are extensive, little is in print concerning the chemical and physi-
cal constants of the fat as influenced by the breed and individuality of
the animal, with the exception of the relative size of the fat globules.
Veith! studied the milk of 3 breeds of cows and concluded that the
breed does not have any appreciable influence upon the nature of the
fat. Kirchner? states that the composition of the fat is dependent
mostly upon the stage of lactation and the food of the animal, but also
varies to some extent with the individual animal.

The object of the investigations herein reported, as far as the varia-
tions due to breed and individuality are concerned, was especially to
gather data concerning the fat. Since the rations fed the animals was
uniform in all cases, the variations found can reasonably be attributed
to the influence of the breed or of the individual.

RELATIVE SIZE OF THE FAT GLOBULES.

The determination of the relative size of fat globules was introduced
by Babcock.’ <A description of this method of measurement is also
found in Bulletin 111, Bureau of Animal Industry, United States
Department of Agriculture. The method is essentially one of com-
paring the average volumes. It has been observed by several inves-
tigators that the breed of the animal has a decided influence upon the
size of the fat globules. Jones‘ found that the milk of the Holstein
had a much larger proportion of small fat globules, while the Jersey
and the Guernsey had the largest, the Ayrshire standing between.
Woll® gives the following data concerning the size of the fat globules

1Vieth, P. Butterfett-Untersuchungen nach Reichert-Wollny’s Methode. Milch Zeitung, vol. 18, no,
28, p. 541-545. Bremen, July 10, 1889.

2Kirchner, W. Handbuch der Milchwirtschaft. Berlin,1898. See p. 16.

3New York Agricultural Experiment Station, Fourth Annual Report (1885), p. 293-302. Albany, 1886.

4Jones, L. R. Study of milk globules. Vermont Agricultural Experiment Station, Fourth Annual
Report (1890), p. 65-69. Burlington, 1891.

5 Woll, F. W. The fat globules in cows’ milk. Wisconsin Agricultural Experiment Station, Eleventh
Annual Report (1894), p. 223-239. Madison, 1895.

20 INFLUENCE OF BREED AND INDIVIDUALITY ON MILK.

in the milk of the 3 breeds which were entered in competition at the
Columbian Exposition at Chicago in 1893:

Relative
Brood. || puMbeE. | “sige ot | ANemaee
? globules. "

| “

Microns.
JONSGY scot = ae ele 25 290 3.95
Guernsey... ..--.- 25 217 3. 58
Shorthorn.....-..- 24 L7% 3.35

Gutzeit! gives the average diameter of the fat globules in his inves-
tigation as follows:

Microns.
JOVSCV RL Oe eee canes Suc Se ee 2 ee ok Se ei ee ee EE tReet eens 3. 50
Shorthorn: sca toe os: Mees a ee ee. es ee ei ee 2.76
olstemity 2 ii. 5 eek ae, Lt ae BA Se SMA Cp eee 2.58

Table 12 gives the relative size of the fat globules as determined for
each of the 11 animals used in our investigation and the averages for
the breeds. This table shows the same results as noted by others, the
Jersey having by far the largest fat globules, while the Holstein have
the smallest, the Shorthorn standing between the Holstein and the
Jersey. The comparative size of the fat globules in the milk of these
4 breeds is illustrated graphically in figure 1. The chief difference

Gee

AYRSHIRE HOLSTEIN
JERSEY SHORTHORN

Fic. 1.—Relative size of the fat globules in the milk of dairy cattle.

between the size of the fat globules with the different breeds is that
with the Jersey there is a greater proportion of the larger globules and
that the milk of the other breeds contains a limited number as large
as the largest in the Jersey milk. The milk of the Holstein breed is
especially noticeable in containing alarge number of small fat globules,
together with a wide variation in size.

The table shows that the individuality of the animal has some influ-
ence upon the size of the fat globules, but it is of less importance than
the breed characteristic. The milk of an Ayrshire or a Holstein can
be distinguished from that of a Jersey with considerable certainty by
the characteristic of the fat globules alone. The Shorthorn, on the

1Qutzeit, Ernst. Die Schwankungen der mittleren Grosse der Fettkiigelchen in der Kuhmilch nach
Laktation, Fiitterung und Rasse, sowie tiber den physikalischen und chemischen Unterschied der

grossten und kleinsten Fettkiigelchen. Landwirthschaftliche Jahrbiicher, vol. 24, p. 539-667. Berlin,
1895. See p. 648.

RESULTS OF THE EXPERIMENTS. 21

other hand, has fat globules that in many cases are as large as those
contained in the milk of the Jersey, although less uniform in size.

TABLE 12.—Relative size of fat globules in milk of each cow, and breed average, by 4-week

periods.
Jerseys. Ayrshires.
Four. week period No. Average Average
No. 4. No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires.

363 DO) Psy ns 459 235 232 234
423 BOO Wesco a Soe 381 163 189 176
370 325 417 371 148 142 145
229 274 879 461 135 155 145
267 264 358 296 115 165 140
267 349 373 326 133 178 156
235 370 301 302 93 163 128
299 367 334 333 80 151 116
318 270 335 308 75 146 111
228 209 259 232 129 114 122
167 263 342 OM |stsssiseiers. =’: 146 146
Seer a 315 229 Xe Aes Sas 93 93
De giaial 32 (o'Ske | appeyerastegeic. 438 CS Te ce ACRE 110 110

Rs RE lb ly? 461 AGE eo eGsorcse lee ad See ee alsceed eee

True average of relative
size of globules.......--- 309 336 338 328 141 160 150
Holsteins. Shorthorns.

Four-week period No. Average Average

No. 205.| No. 206.| No. 209. for No. 400.|No. 402.) No. 403.| for Short-
Holsteins. horns.
242 253 321 272 442 566 357 455
147 269 139 185 593 561 303 486
148 124 136 136 317 394 213 308
147 157 138 147 245 274 183 234
127 134 104 122 250 280 134 221
82 155 89 109 277 232 141 217
107 132 98 112 231 271 146 216
96 110 99 102 197 214 147 186
98 96 105 99 214 213 203 210
90 74 79 81 179 193 175 182
81 79 63 74 1940 |e eas 128 161
UT eilise ears errs 76 OTN ie boo aan eaeve PRET ine ahreenerelt tek eee lea oi
iy eee se 118 TTT es =) eRe Rule cect erctets achat llarrers ere ae oe
ROMs ererree tee sieisneceis il Ae 1a eee Bee meet eee pmelfeee Se atce
True average of relative

size of globules.......... 127 164 134 142 311 353 211 282

THE REICHERT-MEISSL NUMBER.!

The results for the Reichert-Meiss] number are given in Table 13.
The Holsteins show the lowest figure for the number, although the

1 This and the two succeeding constants of the fat were determined by official methods, the details of
which may be found in Bulletin 107 (revised), Bureau of Chemistry, U. S. Department of Agriculture.
For the benefit of those who may be unfamiliar with the terms the following explanation may be helpful:
The Reichert-Meiss] number is an arbitrary measure of the volatile acids of which butyric is the principal
one in butterfat. The figures do not show the percentages of the acid, but serve as a means of comparing
different fats with reference to their volatile constituents. The iodin absorption number indicates rela.
tively the amount of iodin a fat willabsorb. Since the only fatty acid found to exist in butterfat which
has the property of absorbing iodin is oleic acid, the iodin absorption number shows relatively the amount
of this fatty acid present, but in common with the Reichert-Meiss] number the figures do not represent
percentages. The saponification number is the number of milligrams of potassium hydroxid required
to saponify 1 gram of fat. Since the amount of potassium hydroxid required depends upon the molecular
weight of the fat the saponification number serves as an indicator of the relative percentages of the fatty
acids of high and low molecular weights present.

22 INFLUENCE OF BREED AND INDIVIDUALITY ON MILK.

Ayrshires on the average are only 0.5 higher, while the Shorthorns
and the Jerseys show a somewhat higher figure. The individual
variations are very marked in the case of Jersey No. 118 with an
average of 23.28, which is the lowest of the entire number. If the
data of this individual was not included the average for the Jersey
would be considerably higher than any of the other breeds. With
the exception of this individual there is no marked variation that is
to be attributed to the individuality of the animal. The marked
variation in the Reichert-Meiss! number due to the advance in the
period of lactation is evident from the table.

TaBLeE 13.—Average Reichert-Meissl number for each cow, and breed average, by 4-week

periods.
Jerseys. | Ayrshires.
Four-week period No. Average | Average
No. 4. No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires
LP St. Ste en eA Sete Ce 29. 22 30.16 29.54 29. 64 27.66 30.59 29.13
DINE, Nise ude bam ree a 28. 72 28. 88 23. 28 26.96 28. 96 27.09 28.03
Be SO aa SOE O Sae ED Coase 28.52 32.09 24.14 28. 25 27.76 26. 58 27.17
AB Ae Soe Soe ee ne 28.50 30. 95 23. 69 27.71 25.76 25.13 25. 45
See ras nee ane ce ee 28. 96 27. 67 23.90 26.84 26. 83 24. 88 25. 86
(AES Sees Joe gee mere sorceerie 29. 20 31.21 24. 64 28.35 25.76 26.79 26. 28
Men St. Sod J. 5s Ae eee 26. 87 27.03 26. 66 26. 83 24.57 25.59 25.08
SEs 28 2 EE SOF. ee. EES 28. 63 27.54 23.12 29.76 23.87 26. 40 25.29
GE oye Sai de saan b see ec eee 25.24 27.03 25. 04 25 77 23.09 24.42 23.76
1 ee See ne Pee eo SOS me 25.95 25. 83 22.85 24.88 17.96 24.36 21.16
WS oe See a. ort ee ce iels coca ERT eee 24.73 22.79 SOTO = Maceece sc 18.09 18.09
Woe ens SRS: oe. ee eS 18. 43 20. 22 iN 6S 5 i seats Sree 21.72 21.72
1 | a ee 8 I Ras A A ee eel Ee 14. 23 1 78 ih eh Ee 20. 67 20. 67
1 | Va PO ah eee ners Rees) Stee C8 PRIS the Os > eae 14. 21 LAT oseasacealsceene come pene
True average of Reichert-
Meiss!] number......--- 28.17 28.69 23.28 26.73 26. 34 Zone 25. 93
Holsteins. Shorthorns.
Four-week period No. Average Average
No. 205. No. 206.) No. 209. for No. 400.) No. 402.|No. 403.) for Short-
Holsteins. horns.
te ee Ge Aas Pee ey eo ee 26.66 | 30.15 | 25.65 27.49 | 30.77 | 30.72 | 29.36 30. 28
PUN, a a aay vipa Saree les 1s 26.01 | 29.48 | 26.84 27.44 | 29.31 | 27.14} 26.67 27.71
Bikes nae Sete ee eee eae 26.33 | 28.15 | 25.10 26.53 | 25.95 | 26.69] 26.31 26. 32
Here he ais Coenen er cote ae 27.38 | 24.58) 27.05 26.34 | 25.99 | 25.60] 26.30 25. 96
rE ee ee ee eae 27.82 | 27.19 | 24.82 26.61 | 28.58 | 26.07; 25.69 26.78
OS Dear Aleitaec Sees oeee ee eee 26.92 | 24.51 | 24.68 25.37 | 26.54] 24.12 | 26.02 25.56
Tee Sane ek Sep See eRe 28.05 | 24.28] 22.79 25.04 | 24.70 | 23.75 | 26.38 24.94
BOP eee ee oy eT ee ne eee ee 27.53 | 28.39 | 23.47 24.80 | 25.99 | 22.93 | 24.53 24. 48
QIU TAA: SPS DSM CER ASRS 27.86 | 23.53 | 24.23 25.21 | 24.46] 18.39] 23.27 22.04
1G Re era a RL SR Se 26.06 | 20.76} 20.17 22.33 | 22.57 | 16.61 | 24.25 21.14
AD aes ee, Sa a tt Re oe 25. 63 17.62 || 21.32 Pale DM fe 1 | Ue pee 25.51 23. 88
1 b JO epee Se rh clea) te ees 5 205397 |S-2.- ee 20. 70 BONBON Sees lasce sees lee ceee cel oe See eeee
1Sic ee Tad. Re LOE Mee he 21.14 PESOGi|!2. ceoscg}et. Shs] eet alee eee
WAM aePth ioe steht montecs eee 10h 275 | ie ecealee eee. OST oe ch Aree oe | He oe eel ere
True average of Reichert-
Meiss] number .......... 25.81 | 26.13 | 24.44 25.46 | 26.89] 25.55 | 26.29 26. 28

RESULTS OF THE EXPERIMENTS. 2a
THE IODIN ABSORPTION NUMBER,

Table 14 gives the data in regard to the iodin number for each
individual and for the 4 breeds. It will be observed that with this
constant there is an evident variation due to breed. The Shorthorn
and the Holstein show a noticeably higher iodin number than the
Jersey, while the Ayrshire comes between. The Jersey cow No. 118
shows an individual variation in this respect, as is the case with the
Reichert-Meissl number. If the figures on this animal be left out of
the total the variation with the breeds would be even more marked.
The variation with the breeds, since it shows practically the same for
each individual, seems sufficient to warrant the conclusion that there
is a variation in this constant to be attributed to breed and that the
Holstein and the Shorthorn may be expected to show the highest
figures, while the Jersey is at the other extreme.

TABLE 14,—Average iodin number for each cow, and breed average, by 4-week periods.

Jerseys. Ayrshires.
Four-week period No. Average Average
No. 4. No. 99. | No. 118. for No. 300, | No. 301. | for Ayr-
Jerseys. shires.
Laas ogtBiot BESS ne poe anaes See 31.08 32. 68 39 31 34. 36 32. 58 28. 58 30. 53
Dis Stfuera ded wares asiee werakis aererhs 28. 04 29. 46 36. 33 31. 28 28.70 29.91 29. 31
Ded A SER aU Te aee alee Seer 29. 61 28. 96 32. 54 30. 37 27.69 30. 56 29.13
NS seat! Me Rs Sa oe 29.94 26. 75 28. 69 28. 46 31.91 29.85 30. 88
i iG SE EN Oe REEDS ee, em 28. 84 29.99 31.55 30.13 27.50 30. 93 29. 22
Goin SEE y= Seen See io ce certs 28.03 27.29 30. 43 28. 58 29. 61 30. 31 29. 96
ere ae ee os hoe oes 31. 46 27.93 28. 67 29. 35 35. 30 31.04 33.17
Sy crak eoae AP Gh Sr eae SAE eam 29.75 27.37 32. 49 29.87 37.32 30. 54 33. 93
Cs chriviceagiis: Mes ercrs rites Wee SSS 32. 27 28.71 33. 67 31. 55 35. 23 32. 64 33. 94
LOR copes ete fo retain hot gee sia 32.15 28.80 31. 43 30.79 37.74 35. 11 36. 43
1 ih ait cle: ete EN se Ue 27.61 31.14 A ete a 44.11 44.11
LDP lato ch eee ihe eae aes Cree xe Cea aie 29. 55 32. 37 0s 960 Sueeoeeece 39. 62 39. 62
ME ess TESS b REO a oO ER ICIS ORNS ne pI EAE pepe gD 38. 48 00 48 OLS al 36. 80 36. 80
er reat TASS Sane ke el ee epee aa sess cee 35. 82 BOLOS UE ek erie ee | ere oak es peers rr
True total average......-.- 29.99 28. 87 32.79 30. 52 31.14 32. 06 31.61
Holsteins. Shorthorns.
Four-week period No. | Average Average

No. 205.|No. 206.) No. 209. for No. 400.|No. 402.) No. 403.) for Short-
Holsteins. horns.

24 INFLUENCE OF BREED AND INDIVIDUALITY ON MTfLK.

THE SAPONIFICATION OR KOETTSTORFER NUMBER.

The data regarding this constant are found in Table 15. The varia-
tions that may be attributed to breed are comparatively small. The
Holsteins show a number 1.5 higher than the Shorthorns. This dif-
ference, while comparatively small, seems to indicate at least some
tendency for a variation between these two breeds. With this excep-
tion no special variation can be observed that may be attributed
safely to the influence of the breed. No marked individual varia-
tions are observed, with the exception of Jersey cow No. 118, which
shows individual variations in this as well as in the other constants.
A high iodin number is usually associated with a low Reichert-Meissl
number and a low saponification number. The data of cow No. 118
follow this rule. The variations, however, are not sufficient to justify
any special emphasis being placed upon either breed or individuality
as a factor in causing variations in the saponification number.

TaBLE 15.—Average saponification number for each cow, and breed average, by 4-week

pervods.
Jerseys. Ayrshires.
Lour-week period No. Average Average
No. 4. | No. 99. | No. 118. for No. 300. | No. 301. | tor Ayr-
Jerseys. shires.
230. 6 228. 5 230.1 232.6 236. 9 234.7
poz 224.7 229.9 230. 7 234.1 232. 4
229. 5 229. 6 3007 |) aaohs 232. 0 232. 1
232.3 229. 0 230. 1 224. 8 230. 4 227.6
227.7 230. 2 229. 5 229. 2 227.5 228. 4
231.7 226. 6 229. 1 230. 1 229. 7 229.9
227.3 229. 4 228. 2 224.5 219.6 222.0
239. 8 224.8 231.3 222.0 228. 3 225. 1
234. 3 225. 1 231.3 223.9 228. 4 226.1
231. 4 227.6 231.6 217.2 224.3 220.8
229. 4 237.0 238 Di ene csnee 216. 2 216. 2
219. 6 223.9 22M Silece cece aas 218.7 218.7
Sep eee a cl seepecee 219.5 PON Rapenene ae 221.3 221.3
Resi as Sn Sy ho 219.1 D191 Soke acemnl aka acse cor eee tees
True total average.......- 231.3 228. 6 227.2 228. 9 228. 4 227.9 228. 2
| Holsteins. Shorthorns.
. |
Four-week period No. | Average Average
|No. 205.| No. 206.|No. 209. for No. 400.|No. 402.) No. 403.) for Short-
Holsteins. horns.
—
1S Mg Oem oe ake em ene eye oy): bh LAL A ev 233.4 | 232.3 | 234.3] 234.3 233. 6
Dike shu ote se Wier eee oe eine ela eens | 229.3] 228.3] 280.6 229.4 | 231.7 | 233.9] 225.4 230.3
See SS Ss fae oa eee oe ene 234.3 | 224.2] 229.8] 228.1 227.4
7 hs Rea aR tere A teeiis S= Lh hai a ae 232.9] 233.7] 230.8 232.8 | 230.0] 223.0] 229.9 227.6
Taos AEE ees SESE HARP Se 230.8 | 232.4 | 228.3 230.5 | 229.4] 228.3] 226.4 228. 0
GNSS Sok oe een ec ace 228.7 | 231.2] 229.0 229.6 | 227.2 24.3] 230.1 227.2
TULSA Uae) Nh Eee eee res 228.1] 229.7} 224.0 227.3 | 223.9] 223.7 | 224.6 224.1
See eee Te a oeiee coisa 227.0] 225.6 | 222.4 225.0 | 226.5} 222.7] 225.1 224. 8
bee See ese co miaab cates ase e 225.0} 224.4] 222.0 223.8 | 224.9] 215.8] 223.8 221.5
I ae Kiet ee ent Sy eek nee Ae 223.9} 219.9] 219.2 221.0 | 220.5] 211.5] 226.4 219. 5
UTS ios) SS Sah chee erg a 226.3 | 216.4] 222.0 ZANE iy (ye PAl th] Rae ae 226. 6 221.7
1 aS an et an A eet ia BAO ON ee a ccuae 230. 3 DADS O Netec canine | come eines facenateet=| eerie mete
DR eo eos eee hat ck tee ane eae >All 1 al Veneta 215.3 NOT en wits coc] ss wieaeial Meee aiceal eee = ae
LAS ccs Site tet poms cna QOD ID Wee cicsciega|'s sree P.s D AB ESE Se SSREeece) Geeseera Schone
True total average.........| 228.2] 230.1] 229.1 229.1 | 227.6] 226.9] 227.9 227.6

LT

RESULTS OF THE EXPERIMENTS, 25
THE MELTING POINT OF THE FAT.

The melting point was determined according to Wiley’s method.
An examination of the data given in Table 16 shows a close agreement
in the melting point for all of the animals. Apparently there is no
variation in the melting point that could reasonably be attributed
either to the breed or to the individuality of the animal supplying
the samples. A marked variation is noticeable due to the advance
in lactation period, but this is regardless of the individual or breed.

Table 17 gives a summary for comparison of the constants of the
fat for the four breeds.

TaBLE 16.—Average melting point of the fat for each cow, and breed average, by 4-week

periods.
Jerseys. | Ayrshires.
|
Four-week period No. pone Meets
No. 4. | No. 99. | No. 118. for No. 300. | No. 301. | for Ayr-
Jerseys. shires.
na 26. “G: sie °C Bs °C.
1 oe BCS REC e De Eee 32. 36 24. 94 26. 62 27.97 34. 80 32. 07 34.44
Dea etn a siatee wtoe claire teas se aaa we 32. 63 33. 24 32. 66 32. 84 33.39 33.21
GE Sy PACER EOE Tess 3 33.39 33.36 33.31 33.35 33.45 32.61 33.03
ie ee US coos Ga 32. 25 34. 53 33.31 33.36 33. 54 32. 80 33.17
74) Se ds Oe Jalsa Ame ee 33.30 33.78 33. 80 33. 63 33. 74 33. 85 33.79
(is SS ee Ne ee a ee 33. 44 34. 08 33. 40 33. 64 33. 87 32. 98 33. 43
essere ESS EL eOd 32. 94 34. 07 33. 92 33. 64 33. 83 33. 98 33.90
Beer ee eee ee eS 33. 24 34. 33 33. 66 33. 74 33. 30 33.55 33. 43
ESTEE S. SHSARLEL EE AE RN 33.03 34. 64 33.39 33. 69 33.30 33.33 33.32
Uy eae Sere ee eee aisle es 32.97 33. 81 33. 59 33. 46 34. 04 33.10 33. 57
iL ee 4 oes BCS Rw fe he ee 34. 88 33. 81 Sasson|2. 4 eis 34.35 34.35
[DIS 7 SEG Ss See ee ee |S Seber Ee 34.35 33. 68 GP BYE Bes aaeeaae 33. 23 33. 23
UT 55 Sime) $3 99 Fee oe eee) SS ea, SUN Pee Ae 33.46 BOMAGN Sl oacd ease 33. 28 33. 28
Le A Bee eee | nee ee | ee 33. 50 AscoOh| a> ee sige RSS eee ee a
True total average........ 32. 91 32.95 32. 99 32.95 33.75 33.20 33. 47
Holsteins. Shorthorns.
\ 3 l l |
Four-week period No. | Average | Average
No. 205. No. 206. No. 209. for No. 400. No. 402.| No. 403.| for Short-
} Holsteins. horns.
2 tbe 2G o¢: 2G. 365 SC; °C. °C.
DERE EL eri; ¢0 70eSn heree Pale So ey ae 33.41 | 32.95 | 32.58 32.98 | 33.91 | 32.69] 32.70 33. 10
OL MER SSO.) he, Sera ee = See eT 32.67 | 33.52] 32.16 32.7. 32.99 | 32.79 | 33.32 33.03
See a ease ieee eae cc aeclasne Sci 33.39 | 31.94} 32.06 32.46 | 31.61] 33.20] 32.70 32. 50
CRC SSe ASAEe UR Ur Sete ae 33.76 | 32.06) 31.84 32.55 |] 33.15 | 33.09] 32.60 32.95
SE oe PANNE. SAPS. 33.02 | 32.47 | 33.04 32.84 | 33.01 | 32.95] 33.15 33. 04
(SSE OAR e See en aan tee ae oe Bee 32.93 | 32.47 31.69 32.36 | 33.88 | 33.99 | 32.98 32. 62
Tee toe Re eS SEH! 32.88 | 32.64 32.30 32.61 | 33.63 | 33.76] 32.54 33.31
Bes Sores aoe oe tomes eee a 32:98 | 33.13 | 32.78 32.96 | 34.13 | 33.79 | 32.65 33.52
Oe sao Moss da: Se ee 33.26 | 32.81 | 32.85 32.97 | 34.21 | 34.65 | 33.14 34.00
LU eRe Ste aan Seen: Oe 33.09 | 32.92 | 33.82 33.28 | 35.40 | 36.31] 33.28 34.99
1 ee ae ae ee 33.01 | 38.80 | 33.15 34.99 | 36.49 |.......- 32. 83 34. 66
1D LR Re See op ee eee 325541255... 35. 45 ERY ae eres Berens oe Wee ae So eee ee
DDS hE eae bey ae ee es Bae ee VRON rose cae 37.39 BOSOM E hoe cele wean scce cack eeeeceiae
i) eee ea gE a a AB BR LM aie ASS od AB BRI EE cbt pag: cess skal ay ceases
True total average........ aaat0))| a2.en i) roon0e) 32. 88 33.56 | 33.37 32. 89 33. 23

>
26 INFLUENCE OF BREED AND INDIVIDUALITY ON MILK.

TABLE 17.—Average chemical and physical constants of the fat by breeds.

Relative Todin Saponifi- | Reichert-

: : : Melting
Breed. size of fat cation Meissl °
globules, | Umber. | number. number. point.
°C,
VONSOY carta’ sow ce ek ce 5 eae os tee eee 328 30. 52 228. 9 26. 73 32.95
Anvrsanes (yy 2o2% . ks kei ccteaee = a4 alee 150 31.61 228. 2 25. 93 33.47
TOWRA io acc woe eceenae se ne 142 34. 20 229.1 25.46 32. 88

SUMMARY AND CONCLUSIONS.

1. The data presented show the influence of the breed and the
individual upon the composition of the milk and upon the constants
of the fat as evidenced by 11 cows, including 3 each of the Jersey,
Holstein, and Shorthorn breeds, and 2 of the Ayrshire breed. These
cows were kept upon a uniform ration and the samples represent an
entire lactation period for each. A compilation is also given which
includes all complete analyses of the milk of purebred animals for
entire lactation periods published up to the Peas by American
experiment stations.

2. The average percentage of total solids is highest with the Jersey
and lowest with the Holstein. The fat represents 34.9 per cent of the
total solids with the Jersey breed and 28 per cent for the Holsteins.
The relation of the fat to the total solids is influenced by breed espe-
cially and to some extent by the individual in the breed.

3. The data corroborate the well-known facts regarding the
variations in fat content due to breed.

4. The breed exerts a decided influence upon the protein content.
A low average percentage of fat goes with a low protein content,
although the ration is not constant. Breeds such as the Jersey,
having a high fat content in the milk, also have a high protein con-
tent; they also have a higher ratio of fat to protein.

5. The proportion of the total protein present as casein does not
seem to bear any special relation to the breed, although some indi-
vidual variations are observed.

6. The ratio of casein to the fat varies uniformly with the breed.
The variation between the Ayrshire, Shorthorn, and Holstein is slight,
but the Jersey has more fat in proportion to the casein.

7. The sugar content of milk does not show much variation either
with the breed or with the individual. Our data showed a somewhat
lower figure for the Holsteins than for the Ayrshires, Shorthorns, or
Jerseys.

8. The data presented show the well-known breed characteristics
regarding the size of the fat globules, those in the Jersey being the
largest, followed in order by the Shorthorn, Ayrshire, and Holstein.

SUMMARY AND CONCLUSIONS. 27

9. The breed apparently is a factor having some influence on the
Reichert-Meissl number. The highest was found with the Jersey,
while the Holsteins had somewhat lower figures.

10. The influence of the breed is shown on the iodin number. The
Holsteins and Shorthorns have a noticeably higher number than
the Jersey, with the Ayrshire coming between.

11. Little influence due to breed or individuality can be observed
with the saponification number.

12. The melting point of the fat shows no variation that may be
attributed to breed and but little with the individual animals.

13. With the exception of the size of the fat globules, the fat cen-
stants are far less influenced by the breed and the individuality of the
animals than by the stage of the lactation period. The feed of the
animal is probably a greater factor than breed or individuality in
influencing the nature of the fat.

——————————————————
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may be procured from the SUPERINTEND-
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