FACTORS AFFECTING THE ENERGY REQUIREMENT. 



67 



Fries's steer A had in every case a materially lower maintenance 

 requirement than steer B, even when the results were corrected to an 

 equal number of hours standing per day. Computed per 1,000 pounds 

 live weight and corrected to 12 hours standing, the results for avail- 

 able energy were as follows : 



Available energy required for maintenance — Armsby and Fries. 





Steer A. 



Steer B. 





Therms. 



Therms. 





6. 23 



7.06 

 6. 38 



1906 



5.70 





4.86 



6.50 







Steer B was an animal of rather pronounced dairy type and of a 

 nervous disposition, and in all probability his higher maintenance re- 

 quirement is to be ascribed to this fact. There can be little doubt 

 that temperament is an important factor in determining the main- 

 tenance requirement and that there may be a considerable range of 

 individual differences in this respect. 



Similarly, any conditions tending to affect the degree of muscular 

 activity will also tend to affect the maintenance requirement. The 

 steer confined in a stall, for example, is likely to take less muscular 

 exercise and therefore to require a smaller amount for maintenance 

 than one simply confined to a pen or an open yard. The animal 

 comfortably bedded and thereby induced to spend much of his time 

 in lying down will consume a smaller portion of his feed for mainte- 

 nance than one kept under less comfortable conditions. Any sort of 

 excitement is likely to cause increased muscular activity and corre- 

 spondingly increased consumption of food for maintenance. 



CONDITION. 



The condition of an animal — that is, the amount of adipose tissue 

 carried — seems to influence the maintenance ration, at least in 

 the case of cattle. This point was first investigated by Kellner. 1 

 His average result for three fat cattle, as shown in the table on 

 page 43, is considerably higher when computed to the same live 

 weight — that is, per unit of surface — than that for the seven lean 

 animals, viz : 



Unfattened 10. 87 therms metabolizable energy per 1,000 pounds live weight. 



Fattened 15. 05 therms metabolizable energy per 1,000 pounds live weight. 



Only one animal, however, was common to the two groups, viz, 

 steer B, the results on which were excluded from the average of the 

 unfattened animals on the ground that it was abnormally high, since 

 the animal never lay down during the experiments. Curiously 



1 Die Landwirtschlichen Versuchs-Statioioen, vol. 50, p. 245 ; vol. 53, p. 14. 



