3 88 



NUTRITION OF FARM ANIMALS 



to bring the gain of protein up to the capacity of the animal, 

 the percentage utilization would be only 1.23 -f- 2.0 = 62 per 

 cent, while on the other hand if the maximum growth could 

 be secured with 1.73 pounds of digestible protein, the utili- 

 zation would evidently be 100 per cent. 



471. Experimental results. The writer is not aware of 

 any exact determinations of the percentage utilization in the 

 sense just denned, that is, of the maximum amount of protein 

 tissue which can be produced either from single proteins or from 

 the mixed proteins of feeding stuffs, but interesting data regard- 

 ing the utilization of protein by growing animals are furnished in 

 experiments by Fingerling 1 upon calves and by Just 2 on lambs 

 in which the influence of a varying protein supply upon the 

 nitrogen balance was determined. 



Reckoning the maintenance requirement for protein at 0.5 

 pound per 1000 pounds live weight, Fingerling's results for those 

 periods in which the estimated capacity for growth appears to 

 have been fully utilized were as follows : 



TABLE 87. COMPUTED UTILIZATION OF PROTEIN BY CALVES 



1 Landw. Vers. Stat., 76 (1912), i. 



Ibid., 69 (1908), 393. 



