254 FEEDS AND FEEDING, ABRIDGED 



based on the yield of the given cow for the previous month. The 

 average monthly decrease during this period is about 6 to 7 per ct. 

 After this the decrease becomes more rapid, being 9 to 11 per et. for 

 the eighth month, 12 to 18 per ct. for the ninth month, and 12 to 23 

 per ct. for the tenth month, after which the cows are generally dried 

 off. The farther advanced a cow is in lactation, the larger is the 

 amount of feed required for 100 lbs. of milk or fat. 



Influence of condition at calving. — When a good dairy cow calves 

 in a fat condition she will often yield milk containing 1 to 2 per ct. 

 more fat than normal, losing markedly in weight meanwhile. 8 This 

 is due to her strong dairy temperament, which impels her to withdraw 

 fat from her body and put it into her milk. The yearly yield of fat 

 may thus be increased by having cows calve in good condition. Also, 

 when a cow calves in high condition, a seven-day record of fat produc- 

 tion secured shortly after calving is no index to her ability as a long- 

 time producer. Yearly records are therefore far more reliable guides 

 to the value of dairy cows-. 



Influence of feed on richness of milk. — Until recent years it was 

 believed that milk varied in percentage of fat from milking to milk- 

 ing, according to the daily feed and care the cow received. We now 

 know that if the cow receives sufficient nutrients to maintain her body 

 weight, the percentage of fat can not be materially altered for any long 

 period of time by greater or less liberality of feeding or by supplying 

 any particular kind of feed. Cows starved or greatly under-fed may 

 produce milk somewhat poorer in fat than normal. In some experi- 

 ments adding to the ration palm-nut meal, cocoanut meal, or fats, 

 such as cottonseed oil, linseed oil, or corn oil, has slightly increased 

 the percentage of fat in the milk for 2 or 3 weeks, after which it again 

 became normal. In other cases, feeding fat did not even temporarily 

 increase the richness of the milk. Conflicting results have also been 

 secured in trials where cows were fed more protein than actually re- 

 quired for body maintenance and milk production. Even where im- 

 provement resulted from feeding a large amount of protein, the rich- 

 ness of the milk was increased by only one or two-tenths of one 

 per ct. 



The Jersey cow gives milk 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 reverse. Were 

 a piece of skin, clothed with yellow hair, taken from the body of a Jer- 

 sey cow and grafted on the body of a Holstein cow, we should expect 

 the grafted portion to continue growing yellow, Jersey -like hair. In 

 the same way, were it possible to graft the udder of a Jersey cow 



sWoll, Wis. Epts. 1902, p. 117; 1903, p. 115; Eckles, Mo. Bui. 100. 



