STUDIES ON CONFORMATION IN RELATION TO MTT.K 
PRODUCING CAPACITY IN CATTLE 1 
IV. THE SIZE OF THE COW IN RELATION TO THE SIZE OF HER 
MILK PRODUCTION 2 
By John W. Gowen 
Maine Agricultural Experiment Station, Orono, Me? 
: Woll ( 9 , 10)*, Peters (8), Grady (4), 
1 Nevens (7) reanalyzing Woll’s data, 
j and the work of several European 
. workers have shown that as the weight 
of the cow increases, her yield of milk 
and milk solids increases. This fact 
j holds for dairy cattle in the pure breeds 
| and also in the dairy grades. The 
work of these writers further shows 
that the economy of production within 
any one breed is greater for the large 
than for the small cow, because of the 
fact that the small cow needs propor¬ 
tionately more feed to maintain her 
body weight. This difference in the 
requirements of the larger and the 
smaller cows has been interpreted as 
due to the difference in the surface 
areas of their bodies. Thus, while the 
surface area of the larger cows is 
greater than that of the smaller cows, 
proportionally to their weight the 
surface area of the bigger animals is 
much less. As heat radiates from the 
body surface, the food units necessary 
for the larger cows would be propor¬ 
tionally less per given unit of body 
area. As the cow’s capacity to handle 
quantities of food increases with her 
size, the amount of food left for milk 
1 production after maintaining the body 
j weight is proportionally greater for the 
I large than for the small cow. 
Further research may show these 
assumptions to be not entirely correct. 
Harris and Benedict (5) have shown 
that the surface-area formula for basal 
metabolism in men and women is not 
so accurate as a height, weight, and 
age formula. There may well be 
other factors of deeper physiological 
significance which really govern the 
I basal metabolism of the animal, factors 
j which in our crudeness we are inter¬ 
preting as causative when they are 
only correlated with the basic factor. 
Be that as the future may show, it is of 
interest to extend the work of these 
investigators to other measures of size 
in cattle. 
The Holstein-Friesian Cattle Club 
(6) in the early history of their Ad¬ 
vanced Registry took a rather extensive 
series of measurements on their cattle. 
There are 385 of these records, the 
cows ranging in age from 1 year and 6 
months to 10 years and 6 months. All 
records for measurement were taken 
within the year in which the 7-day lac¬ 
tation record was made. Th ese records 
had measurements on height at shoul¬ 
ders, height at hips, body length, rump 
length, body width, thurl width, and 
body girth. The weight, either actual 
or estimated, was given in 339 of them. 
All records contained the 7-day milk 
yields and butter-fat percentages. The 
age also was recorded when the test 
was made. The method followed in 
making the measurements herein re¬ 
corded conform to thefollowing rules: i 
The animal must be brought to stand on a level 1 
place and in a natural position, the feet squarely ' 
under the body, the head at a medium height, and 1 
the neck straight. The two items of height are taken 1 
perpendicularly from the ground to the top of the 1 
animal, the one immediately over the knee and i 
center of the shoulder, and the other over the hook i 
bone to center of the back; the length of body is ! 
taken from the extreme front of the shoulder point 1 
to the extreme rear and highest point of the rump, 1 
diagonally in a straight line; the length of the rump, ; 
from the extreme front side of the hook bone to tbe 
extreme of the rump as described above; the width of I 
the hips, from the outside of one hook bone to the j 
outside of the other in a straight line; the width of 
the thurl from the outside of one thurl bone to the 1 
outside of the other, also in a straight line; the girth 1 
by a tape closely fitting the smallest circumference : 
of the chest; in the latter measurement the tape 1 
must be drawn so closely that a slight movement of ; 
it will move the skin of the animal. If the head is 
lowered from the natural position, this measure- 
1 Received for publication July 14, 1924; issued June, 1925. 
1 This paper is one of a series of investigations in animal husbandry, the continued prosecution of which 
has been made possible by a grant to the author from the Rockefeller Institute for Medical Research. 
The data for this paper are taken from the Holstein-Friesian Advance Registry records. They include 
records for the 7-day milk yield, age of the cow at time of test, height at shoulders and hips, body and rump 
length, body and thurl width, girth, and weight. All measurements are taken according to the rules 
prescribed by the association and by men designated as inspectors. 
3 Papers from the Biological Laboratory of the Maine Agricultural Experiment Station, No. 168. 
1 Reference is made by number (italic) to “ Literature cited,” p. 869. 
Journal of Agricultural Research, 
Washington, D. C. 
19976—25t-6 
( 866 ) 
Vol. XXX, No. 9 
May 1, 1925 
Key No. Me-18 
