May 1, 1925 
Size of Coiv in Relation to Milk Production 
869 
any given variable is equal to the 
original standard deviation minus the 
original standard deviation times the 
square root of 1 minus r square ( SD — 
SD^l—r 2 ). When the height of shoul¬ 
ders is made constant, the variability 
in milk yield of Holstein-Friesian cattle 
is reduced 5.4 pounds. When the 
height at hips is made constant, the 
variability is reduced 4.4 pounds. 
When the body length is made con¬ 
stant the variability is reduced 14 
pounds. A constant rump length re¬ 
duces the variation in milk yield 5.8 
pounds. A constant body width re¬ 
duces the variation in milk yield 10.6 
pounds. A constant thurl width re¬ 
duces the variation 1.7 pounds. By 
making the girth constant the reduc¬ 
tion is 8.7 pounds in milk yield. A 
constant weight reduces the variation 
in milk yield 17.5 pounds. 
From these data it is noted that body 
length, body width, girth, and weight 
are the most important items in relation 
to milk yield and its variation. Weight 
is the most important single element, 
but is closely followed by the body 
length and body width. Were just 
the significant measurements for girth 
to be taken it would be found that 
this measurement is nearly if not as 
important as that of body length. 
The figures given in the above para¬ 
graph may be inverted and the results 
expressed in this way. For cows of a 
constant weight the 7-dav Advanced 
Registry records of Holstein-Friesian 
cattle would vary only to 77 per cent 
of the extent to which they now do. 
If the cows were of a constant body 
length the variation in milk yield would 
be only 80 per cent of that now found. 
In the same way we could convert the 
figures for the other measurements on 
the size of the cow. 
SUMMARY 
The results show that, for these cows 
at average age of 3.9 years and a milk 
yield of 338 pounds for the 7-day period, 
the average measurements are shoulder 
height, 52.8 inches; hip height, 53.8 in¬ 
ches; body length, 62.0 inches; rump 
length, 20.4 inches; body width, 21.3 
inches; thurl width 19 inches; body 
girth, 73.2 inches; and weight, 1,088 
pounds. The variations of these meas¬ 
urements are comparable to those taken 
on the body parts of other animals. 
The coefficients of variation range 
from 3.7 to 15.1. The most variable 
part is weight. The least variable is 
height at hips. 
All of these body measurements are 
related to milk yield, so that an in¬ 
crease in any one of them results in an 
increase of 7-day milk yield. The re¬ 
lation of all measurements to milk 
yield is linear for these data. The 
most important element predicting 
milk yield is weight. Body length, 
body width, or girth, closely follow 
weight in the accuracy with which they 
predict milk yield. 
Increases of one inch produce an 
average increase in milk as follows: 
Shoulder height, 14 pounds; hip height, 
13 pounds; body length, 11.5 pounds; 
rump length, 19.7 pounds; body width, 
21.9 pounds; thurl width, 5.9 pounds, 
girth, 7.4 pounds. An average of 100 
pounds in weight results in an average 
increase of 29 pounds of milk. 
LITERATURE CITED 
(1) Gowen, J. W. 
1920-21. CONFORMATION AND ITS RELATION TO 
MILK -PRODUCING CAPACITY IN JERSEY CATTLE. 
i and ii. Jour. Dairy Sci. 3: 1-32, illus., 1920; 
4: 350-374, 1921. 
( 2 ) - 
1923. CONFORMATION AND ITS RELATION TO MILK 
PRODUCING CAPACITY IN JERSEY CATTLE. III. 
CONFORMATION AND MILK YIELD IN THE LIGHT 
OF THE PERSONAL EQUATION OF THE DAIRY 
CATTLE JUDGE. Me. Agr. Exp. Sta. Bui. 314: 
69-96, illus. 
(3) - 
1924. MILK secretion. 363 p., illus. Baltimore. 
(4) Grady, R. I. 
1917. ECONOMY OF PRODUCTION BY DAIRY COWS. 
A COMPARISON OF LARGE AND SMALL COWS IN 
MILK YIELD. Ohio Agr. Exp. Sta. Mo. Bui. 
(no. 22) 2: 334-338. 
(5) Harris, J. A., and Benedict, F. G. 
1919. A BIOMETRIC STUDY OF BASAL METABOLISM 
in man. 266 p., illus. Washington, D. C. 
(Carnegie Inst. Wash. Pub. 279.) 
(6) Holstein-Friesian Association of America. 
1907-23. ADVANCED REGISTER YEARBOOK. V 
18-34. 
(7) Nevens, W. B. ' 
1919. BREED AND SIZE OF COWS AS FACTORS AFFECT¬ 
ING THE ECONOMY OF MILK PRODUCTION. Jour. 
Dairy Sci. 2: 99-107, illus. 
(8) Peters, J. 
1913. beziehungen zwischen lebendgewicht / 
UND LEISTUNGEN DER KUHE. Deut. Landw 
Tierzucht 17: 252-253. 
(9) Woll, F. W. 
1912. STUDIES IN DAIRY PRODUCTION. Wis. Agr. 
Exp. Sta. Research Bui. 26: 54-135, illus. 
( 10 ) - 
1913. ON THE RELATION OF THE BODY WEIGHTS ■' / 
OF DAIRY COWS TO THEIR PRODUCTION. PrOC. 
Soc. Prom.Agr. Sci. (1912) 33: 23-28. 
