272 SCIENTIFIC FEEDING OF ANIMALS 



Racing and driving horses which have to work at 

 a very rapid pace require large quantities of oxygen, 

 and as the carrier of this is in the blood it is essen- 

 tial to maintain the latter at a certain level, and 

 for this purpose a plentiful amount of protein in 

 the ration is needed. 



For the ordinary work of draught horses, the 

 albuminoid ratio above is ample ; in fact, investiga- 

 tions with cab horses have shown that the animals 

 can be preserved in excellent condition when the 

 ratio is as low as i : 21-28. 



Fat can be given in the food of working animals 

 (oxen and horses) in larger quantities than is the 

 case with fattening cattle, for the muscular exer- 

 tion helps to maintain the appetite, which otherwise 

 tends to diminish. Further, too, the fat does not 

 throw as much work on the digestive organs as does 

 an equivalent quantity of carbohydrate material. 

 A draught ox can be given up to 1 lb. digestible 

 fat for each 1000 lbs. live weight without any in- 

 convenience. 



The quantity of carbohydrates in the ration 

 depends generally upon the work which the animals 

 have to perform and upon the food value of the 

 constituents of the ration. As the heat generated 

 in the body cannot be transformed into work, the 

 digestible nutrients of those foods from which much 

 heat arises directly, do not yield as much energy as 

 the " full- value " nutrients (pp. 57 and 91). 



