162 THE CHEMISTRY OF CATTLE FEEDING 



the corresponding amount of starch, must be correspondingly 

 reduced. This makes it appear as if the requirements of the 

 animal were less than they actually are. The question is 

 further discussed under the head of starch values (p. 2 1 8). 



The simplest way out of the difficulty is not to add the 

 nutrients of the two portions of the food together. It is not 

 necessary or advantageous to do so. They represent essenti- 

 ally different things which, in practice, are usually kept 

 distinct. Farmers are accustomed to think in terms of hay 

 and corn not of a mixture of the two and in a more or less 

 approximate fashion they try to adjust the quantity of the 

 former according to the size of the animal, and that of the 

 latter according to the amount of work done. It is a simple 

 matter to determine suitable rations for maintenance. It is 

 equally simple to determine suitable rations for work, if the' 

 necessary data be known. If these two things are provided 

 for, that is all that is required ; and all trouble and confusion 

 are avoided by keeping them distinct. 



Rations. For practical purposes, the author considers the 

 following a good working rule by which to calculate rations for 

 horses : 



(a) An amount of hay corresponding to the thermic energy 

 required for maintenance. This can be calculated by means 

 of the formula. 



(b) For hard work, an amount of oats or mixed corn corre- 

 sponding to an equal number of kilo-pound-units of dynamic 

 energy. For ordinary or light work the corn should be 

 reduced by from 25 to 50 per cent, of the above amount 

 according to the interpretation put upon these terms. 



(f) The allowance of digestible protein should be not less 

 than i Ib. for each 50 kt. of thermic energy in the mainten- 

 ance ration and i Ib. for every 30 or 40 kt. of dynamic 

 energy in the special food for work. 



Example. A horse of 1000 Ibs. live weight requires 35 kt. 

 of thermic energy, and when put to heavy work should receive 

 additional food equivalent to an equal amount (35 kt.) of 

 dynamic energy. This could be obtained from 19 Ibs. of 

 meadow hay and 14 Ibs. of oats. The total ration would 



