
ADE 2, REPORT OF THE DIRECTOR OF THE 
Tur Source or Fat 1n MItx. 
We have already referred to the statement of Liebig thatit was 
manifestly impossible that the scanty amount of fat in grass and 
fodder could account for the fat present in the milk of the cow, 
but as to the statement it would be far more readily accepted if 
the figures were given which prove it. It may be seriously 
questioned whether any cow fed entirely upon grass or any other 
green fodder will for months continue to produce more fat in her 
milk than careful analysis will show to be present in such grass 
or fodder. | 3 
With a view to determine, if possible, this important question 
interesting to the physiologist and of great practical value to the 
dairymen the following table has been compiled from the data, 
‘secured in the investigations of our cattle, which gives for each 
month of lactation for each animal the number of pounds of crude 
fat consumed in the food and the number of pounds of fat pro- 
duced in the milk, and a study of the table will show results of 
much interest as bearing upon this question. 
The aggregate number of pounds of crude fat and of milk fat is 
given under each column, and under the aggregates of the crude 
fat are given the several percentages which these pounds of crude 
fats represent as compared with the pounds of milk fats. 
The agregate number of pounds of crude fat consumed by these 
animals was 4,587.9 and the aggregate amount of milk fat produced — 
by them was 3,793.4 pounds; oras121 to 100. If we allow upon an 
average 17.4 per cent of the crude fat as impurity, it would still 
leave fat enough in the food to account for all recovered in the milk: 
Upon the right hand of the table are given the averages of each 
animal for each month of lactation, and it is interesting to observe 
that during the earlier months the production of fat in milk is 
considerably in excess of even the crude fat of the food, but very 
soon the amount of crude fat eaten, and the amount produced 
became equal, and by a rather steady increase relatively the 
amount of crude fat consumed becomes at later months of lacta- 
tion, largely in excess of the fat produced in the milk. 
Such a result appears to be in accord with common observa- 
tion, since, as is well known, the cow and other animals, as the 
‘time of giving birth to their offspring approaches, often becomes 
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