160 THE CHEMISTRY OF CATTLE FEEDING 



cheaply as well as most effectively obtained from the more 

 highly concentrated and readily digestible foods, notwithstand- 

 ing the much higher price per ton of the latter. This is not, 

 perhaps, entirely consistent with the practice of farmers and 

 horse-keepers, but it accords well with the experience of those 

 who have been most successful. 



Conclusions. The rations for working horses, then, com- 

 prise two parts one for the simple maintenance of the animal, 

 the other to provide the energy for the performance of work. 

 For reasons of pecuniary economy the former should con- 

 sist mainly of hay or similar coarse fodder, and the amount 

 of it should be determined by the size of the animal, as 

 described in Chapter IX. It should provide about f Ib. of 

 digestible protein to each 35 kt. of static or thermic energy. 

 The latter the portion which provides the energy for work 

 should consist of readily digestible foods. The amount is 

 independent of the size of the animal and should be determined 

 by the amount of work done. It is to be calculated from the 

 dynamic value of the food, and should contain at least i Ib. 

 of digestible protein to every 30 or 40 kt. of dynamic energy 

 in the food. 



Feeding Standard for Working Horses. The statement 

 above does not imply that the constituents of one food are 

 used exclusively for maintenance, and those of another for 

 work. It is not improbable that such differentiation may 

 occur to a certain extent owing to the difference in the 

 digestibility of the two kinds of food, but it is by no means 

 exclusive. Probably, in a theoretically exact ration, all the 

 more readily digestible constituents of both portions would be 

 used for work, and the less readily digestible for maintenance. 

 For this reason, then, and also because any deficiency in either 

 part of the ration can be, at least partially, made up from 

 excess in the other, it is customary to add together the 

 digestible nutrients of the maintenance portion and those of 

 the portion for work. The sum is called a " feeding standard " 

 for working horses. 



For example, if we take the maintenance rations of horses to 

 be the same as those of oxen of similar size, i.e. 35 kt. for an 



