260 ILLINOIS DAIRYMEN'S ASSOCIATION. 



In all animals there is a constant breaking down of the 

 body tissues caused by wear, there is energy expended in keeping 

 up the vital processes and in maintaining the body temperature. 

 The food used to rebuild worn-out tissues and to furnish heat and 

 energy when the animal is at rest, is called the food of main- 

 tenance. For a 1,000 pound cow this food of maintenance 

 amounts to about .7 of a pound protein, 7 pounds carbohydrates, 

 and .1 of a pound fat ; as is given in the first line of Table 1. If a 

 cow of this weight is producing 30 pounds of 4 per cent milk, she 

 will require digestible nutrients about as follows : 



Carbohy- 



Protein, drates, Fat, 

 Tb. lb. lb. 



For maintenance 7 7. .1 



For 30 pounds of 4 per cent milk, (including main- 

 tenance) 2.10 13.48 .58 



A COW of the same weight producing 40 pounds of 4 per cent 

 milk will require a ration containing 2.57 pounds protein, 15.64 

 pounds carbohydrates, and .74 of a pound fat. If her yield were 

 50 pounds of 4 per cent milk, her ration should contain 3.03 

 pounds protein, 17.80 pounds carbohydrates, and .90 of a pound 

 fat. 



In feeding dairy cows, the fact that they should be fed ac- 

 cording to their milk production is frequently overlooked. A cow 

 capable of producing 60 pounds of 4 per cent milk a day, must be 

 fed a much larger amount of digestible nutrients, if she is to pro- 

 duce her greatest yield, than a cow giving only 10 pounds of milk 

 testing 3 per cent. 



This point should be strongly emphasized, for a cow cannot 

 give in her product what she does not receive in her food. By 

 referring to Table 1, the nutrients required for any yield of milk 

 may be easily determined. If the cow weighs more or less than 

 1,000 pounds, a proportional increase or decrease in the food for 

 maintenance should be made. 



From the weight of a cow and the amount of milk she will 

 produce on liberal feeding, the required nutrients may be deter- 

 mined. The next step is to select such feeds as will best supply 



