CHAPTER XXII 

 FEEDING WORKING ANIMALS 



WoHKiNG animals are rapidly being displaced by power 

 vehides. Those now in use in the United States are chiefly 

 horses and mules. Oxen were once employed extensively 

 for farm labor and in lumbering, but these are rarely seen 

 under the yoke at the present time except in remote rural 

 districts. It will be proper, therefore, to treat in this con- 

 nection chiefly of horses that are used for draft and road 

 purposes. 



481. The horse a machine. — In feeding a working 

 animal, the essential product of the food is energy to be 

 used in drawing, walking, or trotting. The latent food 

 energy is made available, as heretofore stated, by the 

 oxidation of the several nutrients into the ordinary 

 products of combustion, and the units of heat or work 

 or other forms of kinetic energy evolved are directly 

 proportional to the quantity of digested food which suffers 

 combustion, just as the possible work of a steam engine 

 under given conditions is proportional to the fuel con- 

 sumption in the boiler. The establishment of fundamen- 

 tal relations between food and work requires on the one 

 hand an understanding of the energy values of food, and 

 on the other hand at least a general conception of the 

 amoimt of work performed. The energy values of food 

 have been considered and it now remains for us to ascer- 

 tain what is known concerning energy consumption by a 

 laboring animal. 



(387) 



