Caer 

New Yorx« Agqricttturat Experiment Station. 305 
i VI. COMPARISON OF DIFFERENT BREEDS OF DAIRY 
COWS WITH REFERENCE TO THE PRODUCTION OF 
CREAM AND BUTTER. 
Merson or Derermintnc Amount oF Borrer Propvuction. 
The butter production is calculated from the amount of fat in 
the milk as follows: From the amount of fat in 100 pounds of 
milk, we subtract 0.16 pound, which represents the amount of 
fat lost for 100 pounds of milk, in skim-milk and buttermilk and 
in handling. The remainder is the amount of fat that goes into 
butter, and the amount of butter which this fat will make is 
found by dividing the remainder by 0.85. The result thus found 
is the amount of butter containing 85 per cent. of fat that is 
made from 100 pounds of milk. To illustrate by example, we 
take milk which contains 4 per cent. of fat. From this subtract 
0.16 pound, the amount of fat lost in the process of butter- 
making, and the remainder is 3.84 pounds, amount of fat in milk 
that is recovered in butter. Divide 3.84 pounds by 0.85 and we 
get 4.52 pounds, the amount of butter containing 85 per cent. of 
fat that can be made from 100 pounds of milk containing 4 per 
cent. of fat. 
The question may be asked, “ What authority have we to say 
that 0.16 pound of fat is lost in butter-making for 100 pounds 
of milk and that the butter contains 85 per cent. of fat?” 
Work here and elsewhere shows that when butter is made by 
the most economical process, the average loss of fat is about 0.16 
pound for 100 pounds of milk. Such work can be done only by 
the use of a first.class separator in the production of cream and 
by skilful manipulation of the cream in the process of churning. 
The average loss of fat in butter making was found to be 0.16 
pound for 100 pounds of milk in the work done in connection with 
the World’s Fair test of breeds, and this serves as the most 
authoritative basis we have at present. So far as our work in 
this investigation in comparing our animals with one another is 
concerned, it makes little difference what allowance we make for 
loss of fat, provided we have one that is uniform; but it is desir- 
able, for the sake of comparison with other investigations, that 
we should have the loss as near the actual working results as we 
can get. 
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