142 INVESTIGATION IN MILK PRODUCTION. 
when she received more than she could take any of the four 
weeks following, showing that she was over-fed the second 
week; that she varied considerably from week to week in 
the daily average of total product yielded; that during the 
first week she yielded 1 pound of product to .57 of a pound 
of nutriment, being nearly twice as much product as she had 
nutriment ayailable for product; that for six consecutive 
weeks the product yielded was in excess of the available 
nutriment; that during the 77 days, covered by the table, 
she had available for product 522.7 pounds of nutriment 
and yielded 521.6 pounds of product; that the daily average 
of net nutriment was 6.788 pounds; the daily average of 
product yielded was 6.774, and returned a pound of product 
to practically a pound of net nutriment. 
While it is clearly shown that the cow was enabled to 
make greater return in butter fat to nutriment consumed, be- 
cause of having stored surplus body fat during the time 
that she was dry, the question suggested is, was it economi- 
cal, considering the extra nutriment required, to provide for 
the gain in body fat sacrificed. By referring to table LX it 
will be seen that it required about 6.25 pounds of net nutri- 
ment to a pound of butter fat, where cows had been in milk 
for some considerable time, and were neither gaining nor los- 
ing in body weight. During 77 days Trust yielded 121.8 
pounds of butter fat and had during that time 522.7 pounds 
of net nutriment, which, under normal conditions, would 
have provided for 83.6 pounds of butter fat. But she lost 
in body weight 140 pounds and produced 38.2 pounds of 
butter fat above the normal yield, losing 3.66 pounds in body 
weight to each pound of butter fat yielded in excess of the 
amount provided for in the net nutriment. 
By making similar calculations from table LII to show 
the influence on yield of dairy products by decrease in weight 
of body, the following table is submitted. 

