234 PRODUCTIVE FEEDING OF FARM ANIMALS 



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 mainten- 

 ance 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 chart, 

 p. 236). 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 manage- 

 ment of a dairy. It is the heavy eaters that produce the largest 

 yields and give the most economical production. 10 



The Value of High-producing Cows. Results obtained in 

 the Wisconsin Dairy Cow Competition, 1909-1911, illustrate in a 

 striking manner the value of high-producing cows. The following 

 table gives some of the main data for the highest, medium, and 

 lowest producers among the 398 cows in the competition for which 

 complete records of production for a full year were obtained. The 



10 Proc. Soc. Prom. Agr. Science, 1912, p. 23; Wisconsin Bulletin 102, 

 p.. 78, and Research Bulletin 26. 



