46 THE ECONOMICS OF FEEDING HORSES 



to make good the protein wear and tear of the body, 

 and the experiments referred to prove that the mini- 

 mum amount necessary is something under Ji lb. 

 daily (0*6 to 0*7 lb.). This amount will maintain the 

 animal in the state of nitrogenous equilibrium, the urea 

 excreted in the urine being exactly proportional to the 

 protein given in the food. If less than this amount of 

 protein is given, the urea excreted still remains at the 

 same level — that is to say, more is eliminated than can 

 have come from the food protein, and therefore it must 

 have been formed from the breaking down of the 

 animal's own proteid tissues, and the animal loses 

 weight in consequence. Further, for the food to be 

 digested to the fullest extent, the nitrogenous ratio 

 should not be wider than 1 : 10, or at the outside 1 : 12 ; 

 otherwise to obtain the necessary protein a large bulk of 

 a poor food has to be given, the digestibility is low, and 

 a considerable part of the nutrients in the food are 

 excreted unused. Thus, while it is perfectly possible to 

 maintain a horse on one foodstuff alone, it is rarely, if 

 ever, economical to do so. The better method is to use a 

 mixed ration, just as in feeding a working animal, but 

 with the wide nitrogenous ratio indicated above, and 

 possessing the necessary value in starch equivalents. 



Such a ration is provided by any of the following 

 mixtures : 



Lbs. 



1. Meadow hay 10 



Oats ... 

 Carrots 



2. Hay ... 

 Oat straw 

 Oats ... 



5 

 10 



10 

 5 

 6 



