
A STUDY OF RATIONS FED TO MILCH COWS. 55 
enough on which to weigh the cows, the weights were esti- 
mated. ‘This estimate was made in each case by the Station 
representative, and it is thought that the errors of judgment 
may run more or less equally through all the herds examined. 
Number of months since last calf.—In most cases the time at 
which the cow dropped her last calf was known. 
Number of months till due to calve.—There was, of course, 
more or less uncertainty in this regard. 
Weights of milk-flow for the twelve days of the test.—The milk 
of each cow at each milking was weighed as soon as milked, to 
the nearest tenth of a pound, by the Station representative. 
Percentages and amounts of butter-fat in the milk.—A sample 
of the milk of each cow, night and morning, was taken, and 
from the combined sample a determination of the quantity of 
butter-fat was made. ‘The Babcock method of fat determina- 
tion was employed. From the percentages of butter-fat in the 
milk, and the total weights of the milk, the daily yields of 
butter-fat were obtained. 
Kinds and weights of foods used.—The feeder was requested 
to use the same kinds and amounts of feeding stuffs during 
the test period as he had previously been using. The quan- 
tity for each animal was weighed by the Station represen- 
tative just before feeding. Any portions of the food left 
uneaten by the cows were carefully weighed, and due allow- 
ance was made for these uneaten residues in estimating the 
amounts daily eaten.’ During the test, usually on the third 
day, samples of each feeding stuff used were carefully taken 
and at once sent to the laboratory for analysis. From the 
results of the analyses and the weights fed, the total nutrients 
(protein, fat, nitrogen-free extract, and fiber) fed each day 
were calculated. By the use of digestion coefficients, estimates 
were made of the weights of digestible nutrients in each day’s 
ration. 
The names and post-office addresses of the owners of the 
herds studied by the Station during the four winters, 1892-93, 
1893-94, 1894-95, and 1895-96, are given beyond, on page 
64, together with the dates at which the Station representative 
was at the farm. At the left, in the first column of figures, is a 
reference number for each test. In the remaining tables, and 
