126 INVESTIGATION 1N MILK PRODUCTION. 
ceived 2.63 pounds of protein they madea daily average 
gain of .2 of a pound, when receiving 2.09 of protein they 
gained .12 of a pound and when receiving 1.90 they lost .13 
of a pound daily. Whether the decrease in gain the second 
year and the loss in weight the third year was due to the de- 
crease in the protein supply or for some other cause does not 
appear. Butitis possible, it might be said quite probable, 
that it was due to the difference in the ratio of grain to 
roughage. During the winter 1901-2 two-thirds of the nu- 
trients in the rations were provided by the roughage, while 
during the winter 1894 5, just half the nutrients were in the 
roughage, and during the winter 1895-6 less than half. The 
fact that the loss in weight during the winter of 1901-2 oc- 
curred with all groups indicates that the cows were required 
to take so much of the daily ration in roughage that the 
nutrient content did not quite meet the requirements of the 
cows for the work they were doing and maintain their 
weight, though they ate to their full limit. 
Reviewing the results obtained, it appears— 
That the rations having a nutritive ratio of 1:7.7 and 
1:9.7, respectively, were as effective in the production of 
milk, butter fat and milk solids as was the one having a nu- 
ELItiVe ratio ol el 6.3. 
That the protein required in milk production depends 
upon the quantity and quality of milk yielded. 
That in the production of butter fat, actually more 
but relatively less protein and other nutrients were required 
to a pound of butter fat with cows giving milk containinga 
high per cent of fat than with those giving milk containing 
a low per cent of fat. 
That in the production of milk solids less nutrients were 
required to a pound with cows giving milk having a low per 
cent of butter fat than with cows giving milk having a high 
per cent of fat. 
It is not held that the decrease in the average daily yield 
and increased nutriment required to a given product was 
caused by the increase in protein supply, or that the in- 
crease in daily yield and decrease in nutriment required to a 
given product was caused by the decrease in protein supply, 

