RATIONAL FEEDING OF ANIMALS 351 



476. Food Requirements of Dairy Cows. For the 



production of milk, a more liberal supply of digestible 

 protein is required than for beef production. From 0.4 

 to 0.5 pound of digestible protein and from 7 to 7.5 

 pounds of digestible carbohydrates are required for main- 

 tenance. A ration should contain, in addition, 1.4 to 1.8 

 pounds digestible protein and 4 to 6 pounds digestible 

 carbohydrates, because milk cannot be produced econom- 

 ically on too scant an amount of nutrients. According 

 to the standard feeding tables, a ration for a cow giving 

 a heavy yield of milk should contain 32 pounds dry mat- 

 ter, 3.3 pounds digestible protein and 13 pounds carbohy- 

 drates. For economic production of milk, this is a larger 

 amount of protein than is necessary. Under average 

 conditions, a ration containing about 27 pounds dry mat- 

 ter, 1.8 to 2 pounds digestible protein, and n to 13 

 pounds digestible carbohydrates will prove more econom- 

 ical than one containing larger amounts of protein. In a 

 milk ration, proteids must be furnished for the produc- 

 tion of the albumin and casein in the milk. In 15 pounds 

 of milk, there is about one-half pound of proteids, as 

 albumin and casein, and this must be supplied from the 

 food. For the production of milk, about as much more 

 protein is necessary to supply the energy to produce the 

 milk as is required for maintenance and the milk pro- 

 teids. In an ordinary dairy ration, about one-fourth of 

 the proteids is recovered in the milk as casein and 

 albumin, one-fourth is indigestible, while one-half is 

 present in the liquid waste and represents the protein re- 

 quired for maintenance and the production of milk. The 



