Mar. 25, 191S Energy Values of Feeding Stuffs for Cattle 479 



somewhat lower than Kellner's direct results just cited. Those on the 

 oil meals appear relatively lower than ours, although even then they 

 are not much lower than those for the coarse feeds, but it ma}^ be ques- 

 tioned whether the estimates of the metabolizable energy of these feeds 

 are not too low. 



FACTORS OP INCREASED METABOLISM 



Even the very approximate and partial analysis of the total heat 

 production which is attempted in the second part of Tables IX, X, and 

 XI serv'es to show that the degree of uniformity noted in the preceding 

 paragraph, so far from being surprising, was rather to be expected. 

 The notion of a greater expenditure of energy on coarse feeds is based 

 on the idea that this expenditure is largely for mechanical work. The 

 analysis of the heat production attempted on preceding pages, however, 

 even though only approximate, clearly shows that a considerable por- 

 tion of the increase in heat production is due to other causes. Roughly, 

 from 9 to 1 7 per cent of the increase is computed to have had its source 

 in the methane fermentation, while from 3 per cent to as much as 30 or 

 40 per cent appears to have been due to increased muscular activity 

 while standing. The " remainder" may be regarded as consisting of the 

 mechanical work of digestion plus the stimulus which the feed exerted 

 upon the general metabolism of the animal. How large the latter fac- 

 tor is we have no means of determining, but apparently it is not incon- 

 siderable. 



It would seem that the energy expended in peristalsis can not be 

 widely different per kilogram for the different classes of feeding stuffs. 

 On the other hand, the work of mastication and rumination has been 

 shown to be distinctly greater for the coarse feeds. On the basis of 

 Paechtner's (39) and of Dahm's (17) experiments on cattle it may be 

 roughly estimated at 100 Calories per kilogram for hay. Zuntz and 

 Hagemann (52) found the work of masticating oats by the horse to be 

 28 per cent of that required for hay. On this basis an expenditure by 

 cattle of approximately 28 Calories per kilogram of concentrated feeds, 

 may be estimated. If these amounts are subtracted from those shown 

 in the last column of Table XI, the following approximate figures are 

 obtained per kilogram of dry matter consumed for the work of peristalsis 

 plus the food stimulus to the general metabolism: 



COARSE FEEDS 



Calories. 



Timothy hay 404 



Clover hay (experiment 179). .. . 346 



Mixed hay 6S5 



Alfalfa hay 802 



Maize stover 775 



CONCENTRATES 



Calories. 



Maize meal 878 



Hominy chop i, 152 



Wluat bran 915 



Grain mixture No. i 803 



Grain mixture No. 2 872 



Whether the expenditure of energy in peristalsis in cattle is as small 

 as it appears from recent investigations to be in man and in the car- 

 nivora it is impossible to say, but one can hardly avoid the impression 

 that the considerable differences shown b>^ the foregoing figures, and 



