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 an 

 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-oil produces a 



