QUANTITY OP FOOD REQUIRED. 65 



animal being required to undergo any extra exertion, has been 

 variously computed ; but it is now pretty well ascertained that 

 the essential diet for a horse, in a state of quietude, for twenty. 

 four hours, should be made up as follows : — 



' Albumiiioids ... 



Fats 



. Carbo-hydrates 



Salts 



Being a total of Food, free from water, of 



This is calculated to possess potential energy capable of 

 producing force equal to 27,855 foot-tons. And if the weight 

 of the horse is estimated at 1,000 lbs., he would require 87*3 

 grains for each pound of body weight ; or the whole body 

 would require about 1 •80th part of its weight in food every 

 twenty-four hours, the animal undergoing no toil of any kind. 

 A pony weighing 440 lbs. requires forty-six grains of nitro- 

 genous material for each 2 lbs. 3 J oz. of weight. 



This essential diet is supposed to be theoretically totally 

 devoid of water, but in reality it would contain from fifteen to 

 twenty per cent, of that fluid ; so that, to allow for it, some- 

 thing like 1-87 lbs., or 2-49 lbs., must be added to the 12-472 lbs. 

 just referred to. Such is the subsistence ration, with its heat- 

 forming and energy-producing constituents, which will main- 

 tain the vital powers of a horse in a normal condition for a day. 

 The additional food required to enable the body to perform 

 what may be called " external work," in contradistinction to 

 that performed within the body, and which may be designated 

 " vital " or " internal work," must depend upon circumstances, 

 Buch as the amount and severity of the labour, and the 

 conditions in which it is performed, as season of the year, 

 locality, etc. 



The weight of the horse, it may be noted, does not give us 

 P 



