THE COMPUTATION OF RATIONS 



701 



For the production of 20 pounds of 4 per cent milk there would 

 be needed, according to Table V : 



Digestible protein (0.05 X 20) . . . . i.o pound 

 Net energy (0.27 X 20) 5.4 Therms 



The total feed requirements per day and head are therefore : 



The problem, then, is to find a mixture of the available feed- 

 ing stuffs which will yield these amounts of digestible protein 

 and of energy, and which shall have a suitable bulk. 



The first step in the construction of a ration is to fix upon the 

 amounts of coarse fodders. It is usually desirable to use as 

 large a proportion of these as possible, since they are usually 

 cheaper sources of feed than grain. On the other hand, the 

 amount of them which an animal can consume is limited. Much 

 depends upon the individual animals, and the proper amount 

 can only be told by trial, but we should probably aim to get 

 from 12 to 14 pounds of dry matter in the form of coarse fodder. 

 Corn forage being a cheap feeding stuff, we shall naturally use 

 this freely, with probably some hay for variety. By a little 

 trial, we find that 10 pounds of corn forage and 6 pounds of clover 

 hay will give us 13.4 pounds of dry matter and the amounts of 

 digestible protein and of energy shown below : 



