252 



Journal of Agricultural Research voi. xvm, no. $ 



Table VI. — Percentage of protein in gain 

 (Results expressed in percentages! 



a Steer 663 removed at end of thirtieth week. 



b Amount of protein stored greater than gain in live weight. 



e Steers 650, 666, and 652 were on full feed in period 5. 



<* Steer 652 removed at end of thirty-fourth week. 



From this table it is seen that there is no indication that the steers 

 getting the larger amounts of nitrogen and energy showed any larger 

 proportion of protein in their increase in live weight. Neither is there any 

 indication that there was any difference in the percentage of protein 

 in the increase in live weight during any period because of differences in 

 the ration or differences in the age of the steers. Considering the average 

 of all steers for the entire 37 weeks of the experiment, we find that 14.71 

 per cent of the total increase in live weight was protein (nitrogen X 6.25). 



Jordan/ in an experiment with steers between the ages of 23 and 33 

 months, found by means of comparative slaughter tests that the increase 

 in live weight during this time contained 13.57 P^r cent of protein. 

 Waters, Mumford, and Trowbridge,^ at the Missouri Experiment Sta- 

 tion, found by means of comparative slaughter tests upon steers of 

 similar age and size that the first 500 pounds of gain — that is, the 

 increase in live weight from 748 to 1,248 pounds — contained 11.9 per 

 cent of protein. Thus it is seen that while the method of experimenta- 

 tion used by Jordan and by Waters was entirely different from our own, 

 yet quite similar results were obtained. 



PERCENTAGE OF DIGESTED PROTEIN RETAINED 



Table VII shows the percentage of the digested protein which was 

 retained in the body by the individual steers. With the exception of 

 the maintenance steers in period i , there is no indication that the steers 

 receiving larger amounts of digestible protein and net energy stored 

 any more of the protein digested. In period 2 all steers stored less 

 protein than they did in period i , although there is no distinctive differ- 

 ences between lots. This decrease (from an average of 41.64 per cent 



' Recalculated by Armsby. (Armsby, H. P. nutrition OF farm animals, p. 372. New York, 1917.) 

 ' Bull, Sleeter. principles of feeding farm animals, p. 52. New York, 1916. 



