34 



NUTRITION OF FARM ANIMALS 



indiscriminately or used as a basis for exact computations of 

 the effects of feeds in individual cases. 



3. FACTORS AFFECTING THE MAINTENANCE REQUIREMENT 



Certain conditions which affect the energy expenditure of 

 the fasting animal, and therefore the amount of net energy 

 required for maintenance, have already been discussed in Chap- 

 ter VII (345-357) , while a few others may be more conveniently 

 considered at this point. 



391. Temperament. The nervous, restless animal is con- 

 tinually expending energy in a variety of unnecessary move- 

 ments which may very materially increase the amount of energy 

 needed for his maintenance as compared with that required 

 by the quieter and more phlegmatic animal. There can be little 

 question that those differences between the maintenance re- 

 quirements of different animals which are ascribed somewhat 

 vaguely to " individuality " are due to a large extent to vary- 

 ing amounts of muscular activity. 



Thus in Armsby and Fries' determinations 1 of the maintenance 

 requirement of cattle (380) the two animals designated as A 

 and B were respectively a pure-bred beef animal and a scrub, the 

 latter having more or less dairy blood and being of a decidedly 

 more nervous disposition than the animal A. The difference 

 in the requirements of the two animals, as shown by the follow- 

 ing comparison, may be reasonably ascribed to this differ- 

 ence in temperament. 



TABLE 55. NET ENERGY REQUIREMENT FOR MAINTENANCE 



U. S. Dept. Agr., Bur. Anim. Indus., Bui. 128 (1911), p. 53. 



