148 PROFITABLE DAIRYING 



of carbohydrates), add to this the digestible 

 carbohydrates, and divide the sum by the digest- 

 ible protein in the food. In the above, multiply- 

 ing .5 by 2.4 we get 1.2; adding 1.2 to 13 we 

 get the sum 14.2; dividing this by 2.5 we get 5.7. 

 The ratio of the protein, therefore, to the other 

 constituents is 1:5.7, or 1 part of protein to 

 every 5.7 parts of carbohydrates or their equiv- 

 alent. 



The Haecker standard. The Wolff-Lehmann 

 standard has been largely superseded by Amer- 

 ican standards. The best one of these was given 

 to us by Professor T. L. Haecker of Minnesota 

 as a result of his investigation and varies with 

 the amount and quality of milk a cow produces. 

 He first establishes a maintenance ration (the 

 amount of feed required to keep a dry cow at a 

 constant weight), and to this he adds an addi- 

 tional ration necessary to produce the amount 

 of milk which the cow is capable of producing, 

 as will be observed from a study of the following 

 table : 



TABLE III 

 Showing maintenance rations for cows of different weights 



