
NITROGENOUS FEEDING STUFFS. 97 
were fed; and the fat in the milk from cows which were fed 60 to 65 liters of 
corn-distillery slop showed only 15.5 per cent. volatile fatty acids. From this 
it might be concluded that the sesame oil and corn oil, which are nearly free 
from volatile fatty acids, were transmitted to the milk; but if this had been the 
case the melting point of butter made from this milk would have been materially 
decreased. On the contrary, it was considerably increased, being 41.5°, as 
compared with the average melting point of butter of 30. , while that of the oils 
is below o° 
aS ne result of the author’s experiments, as well as of the examination of 
milk from herds to which large amounts of corn-distillery refuse or the residue 
from the manufacture of starch from corn were fed, it was found, as a rule, that 
food rich in oil did not give, as was expected, a milk fat with a low melting 
point, but instead one with an uncommonly high melting point. In other words, 
such food did: not give a soft butter, as is generally stated, but a hard butter 
instead. 
‘“ The fat of the food does not go directly into the milk, but forces into the 
milk body fat, z. ¢., tallow, and thus indirectly increases the quantity of milk’ 
fat. Normal butter fat is certainly a product of the activity of the lacteal glands. 
Its amount can, therefore, not be materially increased by the manner of feeding 
without increasing the secretion of milk asa whole. Unlike the carbohydrates 
and protein, the fat of the food can materially increase the fat content of the 
milk, but only by the body fat produced from the carbohydrates being trans- 
ported to the milk, whereby the fat of the food is probably consumed to keep 
up the oxidation in place of the body fat. 
‘‘From the results obtained the author believes that in purchasing concen- 
trated feeding stuffs for cows special weight should be laid upon high fat con- 
tent. While at present the protein is rated in Germany at about one and a half 
times the money value of fat, in future the fat of concentrated feeding stuffs 
will be considered of at least equal value to protein, and probably of higher 
value. In concentrated feeding stuffs the fat should be guaranteed separately. 
The oil factories should be induced to furnish oil cakes with a higher fat con- 
tent, as was formerly the case before the methods of extraction were perfected. 
‘“These facts, the author believes, throw a new light upon the secretion of 
milk, furnishing a further ground for the belief that the constituents of milk 
result from the breaking down of organized tissue. Ona ration poor in fat the> 
milk fat is newly formed fat of a special kind, distinguished from other animal 
and plant fats by its higher content of volatile fatty acids. On a fat-free ration 
only this ‘normal’ fat (7. ¢., that resulting from the breaking down of milk- 
produciug tissue) can appear in the milk, and its amount cannot be increased by 
adding fat-producing nutrients (carbohydrates) or protein to the food. Fat-free 
food can increase the production of milk fat only by increasing the tissue which 
yields milk by decomposition, in which case the other milk constituents are 
increased in the same proportion as the fat. The feeding of large amounts of, 
carbohydrates can increase the body fat, but not the milk fat, since they do not 
contribute to the formation of milk-producing tissue; when fed in large quanti- 
ties with a ration which is not rich in protein, as hay, they decrease the fat con- 
tent of the milk, because they diminish the proportion of protein in the ration— 
that is, the tissue-forming material (glandular tissue and white blood corpuscles). 

