68 CLEAN MILK 



composition of milk is unaltered by food, the quantity of millc 

 secreted is directly dependent upon the amount and kind of food. 

 The cells of the udder being made of a substance similar chemically 

 to the proteids of the milk, there must be an abundance of protein 

 in the food to constantly rebuild these cells as they liquefy into 

 milk. Indeed, the proportion of protein in the food has to be higher 

 in feeding for milk than for any other purpose. This proportion 

 has been determined by experience and experiments (see Wolff's 

 table below). 



While it is possible to secure the proper proportion of protein 

 by the use of the greatest variety of fodders, the special foodstuffs 

 which may be employed in any given case should be determined 

 chiefly by the local cost of special fodders and the price of milk. 



The richer a food in protein the more costly is it, and, if the- 

 price of milk is low, it may not pay to increase the amount of pro- 

 teids in the food sufficiently to attain to the maximum milk-yield. 

 A food rich in protein tends to sustain the period of lactation and. 

 keep up the flow of milk — which is ordinarily greatest soon after 

 calving — for a considerable period. In case of large milkers which 

 receive an insufficient supply of protein, the proteids of the tissues 

 of the body are called upon to make up for the loss of protein in the. 

 formation of milk from the udder cells, and the animal rapidly 

 loses flesh. 



Notwithstanding the fact that the composition of milk cannot 

 be materially altered by feeding under ordinary circumstances, yet 

 by good feeding and breeding (taking advantage of increased fat 

 yield in milk through careful selection), it has been found possible - 

 in several generations to produce an animal giving milk one per 

 cent, richer than that common to its breed. This has been accom- 

 plished by some in the case of the Holsteins. 



Wolff's original feeding standard for milk cows, per day ancL 

 1,000 pounds live weight, is as follows: 



