60 MAINTENANCE RATIONS OF FARM ANIMALS. 



Nutrients for maintenance per 500 kilograms live weight — Wolff — Continued. 



Experiments. 



Including 

 fiber. 



Fiber-free. 



Grandeau's experiments: 



Horse II 



Grams. 

 3,636 

 3,617 



Grams. 

 3,324 

 3,328 



Horse III 





3,626 



3,326 



Experiments of 1886-87: 



Period I-III 



1,202 

 4,150 

 3,792 

 3,738 



3,342 

 3,429 

 3,329 

 3,364 



Period IV 



Period V 



Period VI 



Average 



3.971 



3,366 





The figures inclusive of the crude fiber, as computed by Wolff, evi- 

 dently correspond approximately with the amounts of metabolizable 

 energy contained in various mixed rations which were sufficient for 

 maintenance. In the earlier experiments, and in those later ones in 

 which approximately equal proportions of hay and grain were con- 

 sumed, the amount is approximately 4,200 grams per 500 kilograms 

 live weight, which, using Zuntz and Hagemann's factor of 3.96 

 calcries per gram, is equal to 16,632 calories. In the later experi- 

 ments, in which a larger proportion of grain was fed, the total 

 nutrients required for maintenance ranged from 3,600 to 3,700 grams, 

 equivalent to from 14,257 to 14,652 calories. In other words, the 

 amount cf metabolizable energy necessary for maintenance varied 

 with the proportion of coarse fodder present, as would be expected 

 from the results with cattle recorded on previous pages. 



The maintenance ration in terms of metabolizable energy, as 

 thus computed, is comparable with that estimated by Zuntz and 

 Hagemann, in the manner explained on pages 55-56, from the total 

 heat production of the animal. That Wolff's results are higher is 

 probably due to the relatively larger proportion of crude fiber in his 

 maintenance rations, since, as shown on page 57, the work is assumed 

 by Wolff's method of calculation to have been done at the expense of 

 the nutrients of the grain, and consequently the remaining portion of 

 the ration, which is regarded as the maintenance portion, was rela- 

 tively poorer in grain and richer in coarse fodder. 



Zuntz and Hagemann 1 attempt to estimate the difference due to 

 the latter fact. They average 31 of Wolff's experiments, divided 

 into two groups, viz, those on light and on heavy work, correcting 

 the actual amount of work done for the loss of live weight and 

 likewise for what they regard as Wolff's error in his estimate of the 

 energy expended in locomotion. They also correct Wolff's estimate 



1 Loc. cit., pp. 4liO-424 ; Principles of Animal Nutrition, p. 546. 



