Dec. 1, 1919 Nitrogen Metabolism of Two- Year-Old Steers 



249 



is generally accepted as the minimum for maintenance of cattle. The 

 curves for the nitrogen balance show that the amount of protein con- 

 sumed during this time was not only sufficient for maintenance but that 

 there was a considerable storage of nitrogen. During this time — the 

 eighth to the twenty-second week — the net energy consumption was a 

 little higher than the usually accepted standard. The steers consumed 

 from 6.7 to 7 therms, while 6 therms are considered the requirement 

 for maintenance. In this connection it may be noted that from the 

 thirty-fourth to the thirty-seventh week steer 656, when receiving 6 

 therms of energy, made a daily gain of % pound per day. 



MCDrr Of 



Fig. 2. — Nitrogen metabolism of steers in the one-third feed lot. 



Note how nearly parallel are the curves showing the nitrogen consump- 

 tion, the total nitrogen excretion, and the urinary nitrogen. The curve 

 lowing the nitrogen balance, while following the general trend of the 

 nitrogen consumption, is much more irregular. Usually a slight decrease 

 in the amount of nitrogen consumed caused a greater decrease in the 

 amount of nitrogen stored, while a considerable increase in the amount 

 of nitrogen consumed resulted in a much smaller increase in the amount 

 of nitrogen stored. 



One-third feed lot. — Figure 2 shows the same data for the two steers 

 of the one-third feed lot. It will be noted that in the same periods the 

 consumption of digestible protein and net energy was considerably 

 greater for the one-third feed steers than for the maintenance steers. 

 Consequently the increase in live weight was more rapid and more uni- 



