478 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



First, calculate the digestible proteids and productive value of 

 the ration. 



The ration is too low in proteids and in productive value. Pro- 

 ductive value may be increased by substituting corn for timothy 

 hay. One pound corn substituted increases the productive value 

 0.206-0.078 = 0.128; so to gain the 0.7 pound desired would take 

 5.5 pounds corn chops. Each pound of corn chops substituted 

 would increase the proteids in the ration 0.068-0.021 : - 0.047 

 pounds, or 5.5 pounds would increase it 0.26 pound. This would 

 increase the total proteids to 1.71, but would still leave a de- 

 ficiency of 0.29 pounds proteids. If we replace corn by cotton- 

 seed meal to supply this protein, we require 0.29 -4- (0.352-0.068) 

 = i.o pound cottonseed meal. 



The calculated ration would then be as follows: 



Pounds 



Corn 7 -f 5.5 i.o = 11.5 



Wheat bran = 6.0 



Timothy hay 12 5.5= 6 -5 



Cottonseed meal = i.o 



Total 



25.0 



Reducing the Cost of a Ration. The commercial prices of 

 feeding-stuffs are often not in proportion to their feeding values, 

 and rations may often be modified so as to reduce the cost of the 

 ration. There are four things to be considered in reducing the 

 cost of a ration: (i) the suitability of the feed to the animal; (2) 

 the cost of the productive value; (3) the cost of the digestible 

 proteids per pound; (4) the cost of the bulk or volume of the 

 feed. 



