Oct. 15. 1921 Influence of Plane Nutrition on Maintenance 121 



In comparing the maintenance requirements of the three groups it 

 should be kept in mind that group I does not represent a high plane of 

 nutrition. The aim was to secure maximum growth with no considerable 

 fattening. Their maintenance requirements as computed in this paper 

 correspond closely to the average of 22 respiration experiments by Armsby 

 and Fries ^ and of 7 by Kellner,^ on cattle in medium condition. 

 A comparison of our results, and of those obtained by other investiga- 

 tions, is given in Table VI. 



INFLUENCE OF AGE 



The ages represented in this experiment vary from 30 days for some of 

 the calves at the beginning of the first period to more than 6 years at the 

 close of the seventh period. Apparently there was no relation between 

 the age and the maintenance requirement of these animals. Some of the 

 steers showed a gradual decrease in the maintenance cost from the begin- 

 ning to the end of the experiment. In such cases it was found that the 

 energy intake per 1,000 pounds had also decreased. On the other hand, 

 steers with an increasing energy intake showed an increased maintenance 

 requirement. Maintenance trials on young animals usually give higher 

 results than have been obtained with mature animals, but if age does 

 influence the maintenance requirement the effect is too slight to be shown 

 in a live- weight experiment of this kind. 



SUMMARY AND DISCUSSION 



There is a close relation between the amount of net energy consumed 

 and the maintenance requirement. Periods of high energy intake were 

 apparently periods of high maintenance cost, while periods of low energy 

 intake were accompanied by a lowered maintenance requirement. 



The averages of the periods discussed show the following daily main- 

 tenance requirements per 1,000 pounds live weight, calculated on the 

 basis of digestible organic matter, and in terms of net energy: Group I, 

 5.777 therms; group II, 4.869 therms; and group III, 4.408 therms. If 

 the maintenance requirement of group I is 100 per cent, that of group II 

 is 84.4 per cent, and that of group III is 76.3 per cent. 



The calculations on the basis of dry matter consumed indicate even 

 greater differences. The maintenance requirements as derived by this 

 method may be compared as follows: Group I, 100 per cent; group II, 

 81 per cent; group III, 69.3 per cent. The estimated maintenance re- 

 quirement of group I, as calculated by this method, is 30 per cent greater 

 than the total net energy intake of group III. 



There is no apparent relation between the age of the animals and the 

 amount of energy required for maintenance. 



' Armsby, Henry Prentiss, op. cit. 



