MEASURING THE USEFULNESS OF FEEDS 



47 



taking and laborious experiments carried on by Armsby 6 in this country 

 with a respiration calorimeter and by Kellner 7 in Germany with a 

 respiration apparatus. These studies have been for the most part with 

 mature steers. While studies of this kind have as yet been carried on 

 with but few feeds, they have already brought out facts of great interest 

 and importance. 



The following table, computed from some of these experiments, shows 

 what becomes of the digestible nutrients and of three typical feeding 

 stuffs when fed to cattle: 



Net energy from 100 Ibs., of digestible nutrients and 

 typical feeding stuffs 



The first column of the table shows the gross energy, or the total 

 amount which would be produced on burning 100 Ibs. of the digestible 

 nutrients or of typical feeding stuffs. With the digestible nutrients 

 no further loss occurs in the feces, but all are absorbed out of the 

 small intestine and go into the body proper. The peanut oil contained 

 no nitrogen, and so no nitrogenous waste from it appeared in the urine, 

 nor did any of it form methan (marsh gas) in the paunch. To digest 

 and assimilate this 100 Ibs. of oil required 174.4 therms of energy, leav- 

 ing 224.8 therms as the net energy value for growth, fattening, work, or 

 milk production. 



When 100 Ibs. of wheat gluten, composed of protein, was digested and 

 absorbed into the body, a loss of 49.2 therms occurred, due to the energy 

 lost in the nitrogenous waste compounds excreted in the urine, which 

 were formed from this protein. No appreciable loss occurred in methan, 

 as proteins are not subject to the fermentations in the paunch and 

 large intestine which produce this gas. There was therefore left 213.9 



Nutrition of Farm Animals, pp. 630-688 ; U. S. D. A. Dept. Bui. 459. 

 'Land. Vers. Stat., 53, 1900, pp. 440-468. 



