Mar. as. is's Energy Values of Feeding Stuffs for Cattle 45 1 



While there is a considerable range in the results of individual experi- 

 ments, nevertheless an estimate of 4.5 grams of CH^ per 100 gm. of 

 digested carbohydrates affords a fair basis for an approximate estimate 

 of the losses of chemical energy in the combustible gases and for com- 

 puting the metabolizable energy of a feeding stuff by means of the ordi- 

 nary digestion experiment combined with the collection of the urine 

 and a determination of the heats of combustion of the visible excreta. 

 The additional labor required for this purpose is so small that it is to 

 be hoped that in future digestion experiments it may be undertaken 

 whenever possible. 



FROM DIGESTIBLE ORGANIC MATTER 



It is possible also to estimate the average metabolizable energy of 

 a feeding stuff from its content of total digestible organic matter, as 

 shown by the ordinary feeding tables. 



The differences shown in Tables III and IV between the metaboliz- 

 able energy per kilogram of dry matter of the different feeding stuffs 

 are due chiefly, as already pointed out, to differences in the proportion 

 of the chemical energy carried off in the feces, so that the metaboliz- 

 able energy per kilogram of digestible organic matter shows a striking 

 degree of uniformity as between different coarse feeds, on one hand, 

 and as between different concentrates, on the other, a fact quite in 

 harmony with earlier results reported by Kellner (26). Expressing the 

 results in therms per kilogram and using for the apparent metabolizable 

 energy of Kellner and Kohler's feeding stuffs the figures computed by 

 Armsby {2, p. 301), we obtain the follo\\'ing averages: 



Metabolizable energy per kilogram of digestible organic matter 

 COARSE FEEDS 



Armsby and Fries: Therms. 



Timothy hay 3-49 



Red clover hay 3-49 



Mixed hay 3-39 



Alfalfa hay and meal 3. 61 



Maize stover 3. 43 



Average 3. 48 



Kellner and Kohler: 



Meadow hay 3-5° 



Oat straw 3. 74 



Wheat straw 3- 31 



Extracted straw 3. 64 



Average 3-55 



78745°— 15 2 



