156 STORRS AGRICULTURAL EXPERIMENT STATION. 
SUMMARY. 
four herds of cows were studied during the winter of 1899 and 
1900. Two tests were made with each herd, covering periods of 11 
or 12 days. In the first test the entire herd was fed a ration 
which was essentially the same for each cow; while in the second 
test the ration was varied according to the yields of butter fat. 
Two grain mixtures were used in the second test. The first, to- 
gether with the coarse fodder used, was called a basal ration, 
which was planned to contain not far from 2 pounds of digestible 
protein daily. The actual amounts of digestible protein in the 
basal ration varied from 1.80 to 2.30 pounds. The second grain 
mixture was called a protein mixture. It was usually composed 
of the feeding stuffs which the farmer was using, combined in 
such proportions as to furnish approximately .3 of a pound of 
digestible protein for each pound of the mixture. 
Lhe plan of feeding in the second test was to use the basal ra- 
tion for all the cows in the test, and to add to this varying quan- 
tittes of the protein mixture according to the yields of butter Joe 
as shown by the results of the first test. Those cows producing 
from .50 to .65 pound of butter fat in the first test received the 
basal ration only, those producing from .66 to .80 pound of but- 
ler fat received one pound of the protein mixture in addition to 
the basal ration, those producing from .81 to .95 pound of butter 
fat received 2 pounds of the protein mixture in addition to the 
basal ration, while those producing .96 to r.10 pounds of butter 
Jat received 3 pounds of the protein mixture in addition to the 
basal ration. 
A comparison of the results of the two tests with each of the four 
herds ts given tn the following table. The figures are averages 
for the total number of cows in each test. 
In three of the experiments the average cost of the ration used 
in the second test was less than that of the one used in the jirst 
test. Lhe cost of producing roo pounds of milk was also less in 
the second test of the same three experiments, while the cost of 
producing r pound of butter was less in all cases. 
The economy of feeding according to the yield of milk or of 
butter fat will depend much upon what yields are taken as a basis 
in feeding. In these experiments there was used about 2 pounds 
of digestible protein for .50 to .65 pound of butter fat, and the 
