ENEBGY VALUES OF BATIONS FOE FAEM ANIMALS. 



23 



The cows average 850 pounds per head and have produced in 

 previous years an average of 20 pounds of milk per day testing 4 per 

 cent of fat. According to the table on page 14, the maintenance 

 requirement of such animals per day and head would be approxi- 

 mately — 



Digestible protein * pound. . 0. 43 



Net energy therms. . 5. 40 



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

 needed, according to the estimates on page 18: 



Digestible protein (0.05X20) pound. . 1.0 



Net energy (0.27 X20) therms. . 5. 4 



The total feed requirements per day and head are therefore : 





Digestible 

 protein. 



Net energy- 

 value. 





Pounds. 

 0.43 

 1.00 



Therms. 

 5.40 





5.40 







Total 



1.43 



10.80 







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

 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 food than grain. On the other hand, the amount of them which 

 an animal can consume is limited. Much depends upon the individ- 

 ual animals, and the proper amount can only be told by trial, but we 

 should probably aim to get from 12 to 34 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 : 



Kind and amount of feed. 



Corn forage, 10 pounds 

 Clover hay, 6 pounds . 



Total , 



Total dry 

 matter. 



Pounds. 

 8.17 

 5.23 



13.40 



Digestible 

 protein. 



Pounds. 

 0.23 

 .29 



Net energy 

 value. 



Therms. 

 4.39 

 2.32 



