ii8 



Journal of Agricultural Research voi. xxii. no. 3 



Table II. — Average daily maintenance requirement as calculated from dry matter con- 

 sumed 



Table III. — Energy expenditure by cattle per loo pounds dry matter consumed 



Ration. 



Roughage : 



Timothy hay 



Alfalfa hay 



Oat straw 



Concentrate : 



Grain mixture No. 2 



Energy ex- 

 penditure. 



Therms. 

 35-47 

 53-03 

 46. 00 



51-76 



The coefficients of digestibility used in these calculations were derived 

 from digestion trials conducted under similar conditions at this Station. 

 These indicated that the digestibility of the ration varied with the rela- 

 tive amounts of hay and grain fed. The factors used are given in 

 Table IV. 



Table IV. — Digestion factors for organic matter 



Inasmuch as the thermal value of a pound of organic matter from 

 grain differs from that of a similar weight of organic matter from rough- 

 age, the Armsby factors ^ previously quoted in this paper could not be 

 directly applied to the values obtained with the foregoing digestion 

 coefficients. Those factors would not provide for the widely varying 

 proportions of grain and hay. The following method, therefore, was 



'Armsby, H. P., and Fries, J. A. op. cit. 



