210 ILLINOIS DAIRYMEN'S ASSOCIATION. 



Let us examine the composition of milk and see the promin- 

 ent part taken by proteids : 



f Carbohydrates = 

 Lactose or 

 Milk Sugar 



Fats = 



Butter Fat } 3.70% 



Milk 



Proteids = 



Casein | 3.40% 



Albumen 



Ash .70% 



Water 87.32% 



L 100.00% 



It will be noted that in every hundred pounds of milk there 

 are 3.4 pounds of. proteids, or over 26 per cent of the total solids 

 in milk. 



The young and growing animal which is constantly build- 

 ing up new tissue, and the cow giving milk, demand more pro- 

 tein than is necessary for the maintenance of the adult animal. It 

 has been estimated, or rather determined by experiment, that an 

 adult animal weighing 1,000 pounds requires about .7 lbs. pro- 

 tein, 7 lbs. carbohydrates, and .1 lb. fat, to maintain its body 

 in good living condition; 26 pounds of average milk contains 

 nearly one pound of protein. From this it is evident that a cow 

 of the above weight, giving 3 gallons of average milk daily, must 

 be supplied with about 2 pounds of digestible protein in her daily 

 ration. As the flow of milk increases, the supply of digestible 

 protein must be increased. It is now believed that the cow giving 

 a medium amount of milk should be fed a ration in which there is 

 one pound of protein to about 7 pounds of carbohydrates and fat, 

 (the fat reduced to the basis of carbohydrates, and that the pro- 

 portion of proteids should be increased as the flow of milk in- 

 creases. The ratio of these nutrients in milk, itself, is about 

 1:3. 



Now let us examine our common foods and see which are 

 the best adapted to furnish this protein. 



