390 Feeds and Feeding. 



individual as fixed by breed and selection, and directly on feed, care, 

 and environment. In the state of nature the cow provides only suffi- 

 cient milk for the nourishment of her young, even tho her feed be 

 abundant. When she is liberally fed, the modern dairy cow, pro- 

 duced thru long-time selection and breeding, secretes far more milk 

 than her calf can utilize. So generous is the dairy cow that few 

 dairymen feed to the limit of profitable production. Within wide 

 limits, then, the quantity of milk a dairy cow yields is directly de- 

 pendent on the feed and care she receives. (602) 



617. Feed and richness. — Down to the most recent times it was 

 universally held that milk varied in richness, or percentage of fat, 

 from milking to milking, according to the feed and care the cow 

 received. We have now come to know that the milk of each cow 

 possesses a fixed inherent composition, and that normally the rich- 

 ness of milk is not the immediate sequence of feed and care. No 

 longer does the man whose milk falls below standard some morning 

 at the factory hide behind the statement that he "forgot to give the 

 cows their grain last night." The Babcock milk test has silently 

 but eftectually dispelled this illusion so long held by dairymen. In 

 confirmation of this view the following is offered : 



The Jersey cow gives milk which is relatively rich in fat, and the 

 Holstein milk that is relatively low in fat. No kind of feed or care 

 will cause the Jersey to give milk like that of the Holstein or the re- 

 verse. Were a piece of skin, clothed with yellow hair, taken from the 

 body of a Jersey cow and grafted on to the body of a Holstein cow, 

 we should expect the grafted portion to continue growing yellow 

 Jersey-like hair. In the same way, w^ere it possible to graft the udder 

 of a Jersey cow on to the body of a Holstein, we wpuld expect the 

 Holstein to then give Jersey-like milk. It is not the body of the cow 

 or the digestive tract, but the glands of the udder that determine 

 the characteristics of the milk yielded by each individual cow. After 

 all, this is what we should expect, for if milk varied with every 

 slight change of food and condition, the life of the young, depend- 

 ent on such milk, would always be in jeopardy. (602-3, 606-9) 



618. Fat variations.— Accepting the fact that the percentage of 

 fat in milk is relatively constant, there are nevertheless many com- 

 paratively small variations from the normal, among which are the 

 following: The milk of the heifer is usually slightly richer than that 

 of the cow when mature; (598) immediately after freshening, espe- 

 cially if the cow is in high condition, (599) and again when drying 

 off, the milk is richer than normal. The cow in very poor condition 



