234 PRODUCTIVE FEEDING OF FARM ANIMALS 



of protein and digestible nutrients in the ration, the quality of the 

 milk is not affected by a more liberal system of feeding or by fur- 

 nishing any special feed or combination of feeds. Underfed or 

 starved cows produce milk of an abnormally low fat content, and 

 this may be readily raised to the normal percentage for the indi- 

 vidual cow by increasing the feed. On the other hand, by feeding 

 rations high in protein, a cow will give milk of the highest fat con- 

 tent of which she is capable, but any improvement in quality that 

 may be wrought by such feeding is small, within one or two tents of 

 one per cent above normal at the most. A slight improvement in the 

 composition of the milk has been observed in some cases by feeding 

 single feeds, notably palm-nut meal and cocoanut meal, and by 

 feeding fat or oil, but the evidence with regard to this point fur- 

 nished by different experiments is often conflicting, and in cases 

 where greater differences were found as a result of a certain system 

 of feeding there was a gradual return to normal after a couple of 

 weeks or before, when the cows became accustomed to the feed. 

 In general, both dairy farmers and scientists are now agreed that 

 it is impossible to change materially the percentage of fat in a 

 cow's milk by the feed; no amount of rich feeding or supplying 

 special feeds will change the milk of a Holstein to a composition 

 similar to that of a Jersey, or make low-testing cows or families 

 into " high testers." The largest improvement in quality that can 

 be hoped for would be within a few tenths of one per cent. " The 

 quality of the milk which the cow'produces is as natural to her as the 

 color of her hair" ; it is a practically fixed character that is intimately 

 connected with the functional activity of the mammary gland. 



Influence on Quantity of Milk. — The feed eaten by a cow in- 

 fluences in a marked manner the quantity of milk secreted, and 

 determines the production that the cow will make, up to the capacity 

 of her mammary glands. The feed is, therefore, of primary im- 

 portance in the management of a dairy, and the problem before 

 the dairy farmer is to provide feed for his cows that will secure the 

 largest production of which these are capable, at a minimum cost. 

 As it is only the excess of feed eaten over and above mainte- 

 nance requirements that is used for productive purposes, it follows 

 that the more a cow will eat without increasing appreciably in body 

 weight, the larger returns she will yield per unit eaten (see Fig. 

 46). The old saying, "Feed your cow and she will feed you," 

 expresses the practical experience as to the relation of feed to 

 product. With cows of the dairy type that respond to a more liberal 

 system of feeding by an increase in milk production and not by a 

 gain in body weight, this is a safe rule to follow in the management 



