VARIATION OF FAT IN MILK. 75 
year, and as a consequence milk usually tests a little higher in 
the fall. 
Food of Cows.—For a long time it was thought that the 
kind of food had considerable influence upon the fat-content of 
milk, but later experiments in this country, as well as in foreign 
countries, have almost completely demonstrated that food has 
practically no effect upon the quality of milk. Investigators 
agree that foods may affect the fat-content of milk by increasing 
the quantity of milk, without reducing the per cent of fat, thus 
increasing the total amount of fat. Extensive experiments 
were carried on in Denmark, where more than one hundred 
and fifty cows were involved in each experiment, on ten different 
estates, in order to determine the effect of food upon the per- 
centage of fat in the milk. Roots of different kinds, which 
are very succulent, were fed with out reducing the per cent 
of fat. Different concentrated feeds (oil-cake, wheat, bran, 
ground barley, and oats) were also fed with a view of increasing 
the percentage of fat, but without any noticeable effect. The 
New York Station found, through carefully conducted experi- 
ments, that feeding tallow to cows did not increase the percent-- 
age of fat in the milk. 
Soxhlet found that by feeding tallow, in the form of arm 
emulsion, for a considerable time, he was able to increase the- 
percentage of fat in the milk. The Iowa Experiment Station: 
also reported that the percentage of fat could be increased by: 
feeding oil meal. Dr. Lindsey, at the Hatch Experiment: 
Station, Massachusetts, recently found that fat can be slightly 
increased by the use of certain foods rich in oil. 
But on the whole, the results reached so far show that 
different foods have little influence on the percentage of fat in 
the milk. Especially is this so under practical condi- 
tions. 
On the other hand, different kinds of foods affect the compo- 
sition of the fat itself. Gluten meal, in fact all gluten products, 
produce butter containing a high per cent of olein, and usually 
an increase in the volatile fats. Cottonseed-oi? produces a 
