energy for maintenance. In the experiments at this Institute, re- 

 ported on page 9 of this bulletin, the maintenance requirement 

 has been corrected as accurately as possible to an average period of 

 twelve hours standing out of the twenty-four. In the other results 

 mentioned on page 17, this factor has not been taken into account. 

 An example of the apparent effect of this factor is seen in the re- 

 sults upon Ox B in Kellner's experiments, which, as noted, stood 

 throughout the respiration trials. 



Temperament: The nervous, restless animal is continually ex- 

 pending energy in a variety of unnecessary movements which may 

 very materially increase the amount of fuel material necessary for 

 his maintenance as compared with the quieter and more phlegmatic 

 animal. Zuntz & Hagemann, for example, report a respiration ex- 

 periment upon a horse in which the restlessness caused by the pres- 

 ence of a few flies in the chamber of the apparatus increased the 

 amount of body material oxidized by fully 10 per cent. 



The influence of temperament seems to be illustrated by the 

 experiments at this Institute in 1905-07. Steer A of those experi- 

 ments was a pure-bred beef animal of an unusually quiet disposition, 

 while Steer B was a scrub of a decidedly nervous temperament. 

 The maintenance requirements of these two animals per thousand 

 pounds live weight, as shown in the table on page 9, were as fol- 

 lows: 



Available energy required for maintenance. 



Like the temperament, any external conditions tending to af- 

 fect the degree of muscular activity will also tend to affect the 

 maintenance requirement. The steer confined in a stall, for ex- 

 ample, is likely to take less muscular exercise and, therefore, to re- 

 quire 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 con- 

 sume a smaller portion of his feed for maintenance than one kept 

 under less comfortable conditions. Any sort of excitement is likely 



(19) 



