66 THE PRACTICAL HORSE KEEPER. 



an exact estimate of the amount of food required, as the 

 smaller the animal the larger are his requirements in propor- 

 tion, there being a larger expenditure in the latter than the 

 former, because of the vital activity being greater, owing to the 

 comparatively more extensive surface exposed. 



Horses will perform a certain amount of slow work on hay 

 alone, as it is a typical food for herbivorous animals, the sub- 

 stances required by the body existing in it in the best propor- 

 tions ; but to do this a large quantity is needed, as for a 

 moderate-sized horse from 18 lbs. to 20 lbs. of hay are de- 

 manded as essential diet (i.e., to perform "internal work") 

 for twenty-four hoars. 



But, as has been stated, hay alone will not suffice — unless 

 in such quantity that its bulk would prove injurious for heavy 

 work ; and by a mixture of foods we can supply a better diet, 

 and one which will meet all requirements. Indeed, it has 

 been asserted that a cheaper and quite as nutritive " essential " 

 diet for a horse than 20 lbs. of hay is one composed of 11 J lbs. 

 of hay and 6 J lbs. of straw. 



The amount of " variable " diet for working horses depends 

 upon the degree of labour performed, and the kind of labour ; 

 if this be slow and prolonged, there is less waste of energy and 

 of tissue than when it is brief and severe. It has been calcu- 

 lated that the useful work of a horse, which would be repre- 

 sented by 100, with a velocity of two miles per hour, would 

 not be more than 51, with a velocity of 7 J miles, or more than 

 7, with a speed of 11|^ miles an hour. This calculation is sup- 

 ported by the fact that the amount of food necessary for slow 

 work for ten hours will not suffice for more than five hours' 

 exertion at a trot. With increased speed in work, there is an 

 increased demand for nitrogenous substances ; and in a trot or 

 any fast pace it has been shown that for each 7,233 foot- 

 pounds of energy expended, 15| to 24 grains of albuminoids 

 must be allowed. 



