180 Meat Production 



The striking divergence towards the upper ends of the curves may 

 possibly cause the method to be regarded with suspicion. It is, however, 

 precisely this circumstance that tends to confirm it. When the animal 

 was given unlimited food the quantity consumed was 9-9116 kg. of dry 

 matter = 27865 Cal. of metabolisable energy. Of this amount it is com- 

 puted that [9-9116 X 1256 =] 12449 Cal. was expended on the food 

 ingested. When this is deducted and correction for size is made there 

 remains 15140 Cal. all of which would be required for maintenance in 

 the condition of maximum fatness. The curve indicates that this is 

 58 per cent, of body fat. a number which agrees tolerably with the fore- 

 cast previously made. 



In view of the paucity of the experimental data and the conjectural 

 character of the estimates of body fat no great confidence can be placed 

 in these conclusions. It is probable, however, that the diagram repre- 

 sents the general trend of the curve of basal katabolism and, within 

 limits of practical importance^say from 10 to 40 per cent, of body fat 

 — it may be regarded as a close approximation to the truth for this 

 particular animal. 



It has been demonstrated that basal katabolism does not vary as the 

 live weight or as the two-thirds power of the same when the variation in 

 the latter is wholly or mainly due to alteration of condition; that it 

 varies approximately as the two-thirds power of the live weight for 

 animals in like condition is generally accepted. The basal katabolism in 

 fat-free condition, therefore, suggests itself as the natural fundamental 

 unit for estimation of maintenance requirements. The calculation on 

 this basis involves three distinct steps, viz. (1) reduction of observed 

 live weight to fat-free condition, (2) calculation of basal katabolism in 

 proportion to the two-thirds power of the same, (3) rectification of the 

 ■ result according to the observed condition. Assuming the accuracy of 

 the data here considered, this is more concisely expressed by : 



4175-6 ( M(100-/) )f 100 



410-4?'' I 100 I "^ 100-1-247/' 



or log 5 = § log j^^^-^^'^r^^t - log (100 - 1-247/) + 3-8786, 



100 



where / is the percentage of body fat and B is the basal katabolism 

 corresponding to M the observed live weight (kg.). 



Results obtained by use of this formula are tabulated below for com- 

 parison with those calculated in proportion to the two-thirds power of 

 the live weight. 



