MAINTENANCE RATIONS OF SWINE. 



51 



Computed in the usual way, this is equivalent to 2.300 therms per 50 kilo- 

 grams. This is a much higher result than was obtained in any of the other 

 experiments, and in view of the fact that the digestibility of the rations was 

 estimated and that the feed was of a somewhat varied character it seems per- 

 missible to omit this result from consideration. 



The results of the experiments cited, omitting the ones last men- 

 tioned, may be summarized as follows: 



Daily maintenance rations of sheep. 



Kind of experiment, and investigator. 



Metabolizable energy, 



Per 50 kilo- 

 grams live 

 weight. 



Per 100 

 pounds live 

 weight. 



Respiration experiments: 



Henneberg and Stohmann 



Henneberg, Fleischer, and Miiller 

 Hagemann 



Average 



Digestion experiments: 



Wolff, 1871 , 6 experiments 



Wolff, 1892-3, 8 experiments 



Average 



Average of all 



Therms. 

 1. 574 

 1.441 

 1.304 



Therms. 

 1. 475 

 1.358 



1.222 



1.440 



1. 352 



1. 744 i 

 1.841 j 



1.634 

 1. 725 



1.793 



1.680 



1. 483 



It is of some interest to compare this average maintenance 

 ration of sheep with the corresponding results for cattle. If we 

 assume that the surfaces exposed by these two species are roughly 

 proportional to the two-thirds powers of their live weights, the cor- 

 responding maintenance ration for a 1,000-pound steer would 



be 1.483 8 = 6.885 therms of metabolizable energy as com- 



pared with an average of 10.50 therms for cattle. While such a 

 comparison is, of course, but a rough approximation, it nevertheless 

 seems to show conclusively that the metabolism of the sheep per 

 unit of surface is distinctly lower than that of cattle. No obvious 

 reason for such a difference suggests itself. That it can hardly be 

 due to the direct effect of the wool in diminishing the radiation of 

 heat will appear from a discussion, in a later section, of the influence 

 of external temperature on the maintenance requirement. 



SWINE. 



Two determinations of the fasting katabolism of swine have been 

 reported by Meissl, Strohmer, and Lorenz. 1 The experiments were 

 made with the respiration apparatus, no calorimetric determinations 

 being carried out. 



Computing the energy katabolized by the use of Rubner's factors for the en- 

 ergy corresponding to the nitrogen and carbon excreted, the writer 2 obtained 



1 Zeitschrift fur Biologie, vol. 22, p. 63. 

 - Principles of Animal Nutrition, p. 452. 



