PROTEIN REQUIREMENT OF CATTLE. 



91 



chiefly of grain together with a minhnuni of wheat straw. The results of these 

 experiments are contained in the following table : 



Nitrogen balance per 1.000 pounds live weight — Armsby. 





Digestible in feed. 



Nutritive 

 ratio 1: 



Odin or loss 



Jkxperinieni . 



Crude 

 protein. 



True 

 protein. 



of nitrogen. 

 t)v 1)0 dv. 



Experiment I: 



Steer 1 



Pound. 

 0.30 



Pound. 

 0.26 



20.1 



Grams. 



Steer 2 



. 27 



23 



20. 4 



— . 4 





!31 



. 27 



18. 6 



— 1. 2 



Experiment II: 



Steer 1 



.45 



.38 



13.4 



+1.9 



Steer 2 



.47 



.40 



13.6 



+ 4.2 





.49 



.42 



12.8 



+5.2 



Experiment VI: 



Steer 1 



.62 



.59 



10.9 



+4.7 





.60 



.55 



10.9 



+6.0 





.67 

 .49 



.63 



10.6 



+2.8 



Experiment VII: 



Steer 1 



.31 



23.0 



+5.7 



Steer 2 



.44 



.26 



25.3 



+3.7 



Steer 3 



.51 



.30 



23.9 



+4.4 



Experiment VIII: 



Steer 1 



.62 



.52 



10.4 



+ .2 





.57 



.48 



10.7 



- .1 





.66 



.55 



10.6 



-2.0 













In Experiments II, VI, VII, and VIII digestible crude protein ranging from 

 0.44 to 0.67 pound fully sufficed for maintenance, with a single exception. The 

 range of true protein was somewhat wider, viz, 0.26 to 0.63 pound. The rations 

 of Experiment VII were relatively richer in nonprotein than were those of the 

 other experiments, and the adequacy of these very low protein rations sug- 

 gests a utilization of the nonprotein, although the abundance of nonnitrogenous 

 nutrients, as shown by the nutritive ratio, may also be a factor. The rations 

 of Experiment I were obviously inadequate, even although the supply of non- 

 nitrogenous matter was liberal. 



Experiments upon a steer by xVrmsby and Fries 1 in which the respiratory 

 products were determined gave results in general accord with those already 

 cited. Computed per 1,000 pounds live weight, these results were as follows : 



Witroffen balance per 1,000 pounds live weight — Annbsy and Fries. 





Digestible. 



Gain or loss by body. 



Crude 

 protein. 



True 

 protein. 



Nitrogen. 



Fat. 





1902. 



Pound. 



Pound. 



Grams. 



Grams. 



Period A 





0.45 



0.36 



- 9.1 



-286. 5 



Period B 





.52 



.42 



- 1.3 



- 89.2 



Period C 





.53 



.44 



- .4 



+ .6 



Period D 





.68 



.55 



+12.3 



+ 16.8 





1903. 











Period I 





.66 



.46 



-16.4 



-192.9 



Period II 





.51 



.38 



-15.0 



-350. 8 



Period III 





.70 



.53 



- 2.3 



-169.7 



Period TV 





.97 



.84 



+ 9.2 



+196. 4 





1904. 















.44 



.34 



- 9.5 



-312.7 



Period 11 





.74 



.55 



- .8 



- 75.2 



Period III 





.60 



.46 



- .5 



-155.4 







1 Bureau of Animal Industry, Bulletins 51, 74, and 101. 



