Mar. 25, 191S Energy Values of Feeding Stuffs for Cattle 



469 



the results shown in the second part of Table IX. The "remainder" 

 shown in the last column includes the so-called basal or fasting meta- 

 bolism, together with the effect of the feed in increasing the muscular 

 activity of the organs of digestion and of the voluntary muscles in the 

 lying position, as well as in directly stimulating the cell metabolism. No 

 sufficient data are available for further analysis of this "remainder." 



PROPORTION OF FEED ENERGY EXPENDED IN HEAT PRODUCTION 

 METHOD OF DETERMINATION 



The total metabolism of an animal upon any particular ration, as 

 illustrated by the figures of Table IX, is made up of numerous factors, 

 and a single experiment affords no means of determining the proportion 

 due to the consumption of feed. This can be determined only by a 

 comparison of two periods, otherwise identical, in which different quan- 

 tities of the same feed are consinned, the additional heat production on 

 the heavier ration constituting the measure of the additional energy 

 expended. With camivora and with man the comparison may be made 

 with the fasting state — i. e., the amount of feed in one of the periods 

 may be zero. With cattle this is impracticable for obvious reasons, and 

 it is necessary to make the comparison with a period upon a so-called 

 basal ration. Kiihn and Kellner added the feeding stuffs to be tested 

 to a mixed basal ration that was more than sufficient for maintenance. 

 In our earlier tests, up to experiment 207, inclusive, the same general 

 plan was followed, except that the basal ration consisted of coarse feeds 

 only and was in most cases below the maintenance requirement. In the 

 later experiments the method was modified by feeding different quan- 

 tities of the same feed or mixture of feeds both above and below the 

 maintenance requirement. The method of comparison for a ration con- 

 sisting of a single feeding stuff is very simple. Thus, in experiment 207 

 the following results were obtained on timothy hay with steer A in 

 periods 3 and 4. The same method of comparison may obviously be 

 applied also to different amounts of a mixed ration of grain and hay, 



Computation of energy expenditure by steer A per kilogram of timothy hay eaten 



