THE DAIRY 



189 



2. Food. — The influence of the food of the cows upon the 

 composition of their milk is a matter upon which many varied 

 opinions are held. There appears to be a widespread belief 

 that this influence is considerable, but all experimental evidence 

 shows it to be very small. The quantity of milk is more 

 aflfected than the quality by change of food. There appears, 

 however, to be distinct evidence that a change from a ration of 

 wide albuminoid ratio to one of narrow albuminoid ratio is, for 

 a time, attended with the production of milk slightly richer in 

 fat, but the change is apparently only transient ; and even if 

 the food with the high albuminoid ratio be continued, the milk, 

 after allowance is made for the effect of advancing lactation, 

 shows a tendency to return to its previous composition. 



In any case, it appears that, provided cows are sufficiently 

 fed, change of food has very little effect upon the composi- 

 tion of their milk. 



Certain foods, however, affect the character of the fat in the 

 milk ; thus certain oil-cakes have been noticed to affect the 

 properties of the butter — e.ff., melting-point, iodine value, and 

 proportion of volatile fatty acids. 



3. Ivfluence of Season. — Winter milk is richest, summer 

 milk poorest, while in autumn and spring it is of intermediate 

 quality. This, however, may be partly due to influence of food 

 and mode of life of the animals. 



