254 Western Live-stock Management 



eral wear of the body tissues. They do not need the large 

 amount of net energy which is required when the horse is 

 doing physical work. Since the body has already attained 

 full growth, protein and mineral matter will be needed only 

 to make up for the loss due to the natural wear and waste 

 of the body tissues, while the larger part of the need will 

 be carbohydrates and fats, which are heat-producing. 

 Such bulky feeds as straw and the coarser hays, that would 

 not be suitable for work horses, may be used to advantage 

 in this case. It has been found that the energy required 

 for mastication and digestion of wheat straw is about 

 equal to the total energy of the feed. Therefore, the 

 energy which can be derived from wheat straw and con- 

 verted into actual work is very small, in fact so small that 

 such feeds have little value for hard-working horses. In 

 the case of an idle horse, however, where the chief need 

 of the body is for heat-producing feeds, it is found that 

 this energy from the wheat straw, which was used up in its 

 own digestion and assimilation, is converted finally into 

 heat, and thus serves to maintain the temperature of the 

 body. Thus it is that these foods with very small amount 

 of net energy may be used to advantage in maintaining 

 idle horses. Another point in favor of using bulky feeds 

 for this purpose is that the total amount of digestible 

 nutrients required to maintain a horse in idleness is com- 

 paratively small, and if given in concentrated form, 

 such as some of the rich grains, the horse will not produce 

 enough bulk to satisfy the appetite, and would be very 

 ravenous and not thrifty. Fifrthermore, this small 

 quantity of rich food would be likely to cause digestive 

 disorders. 



The feeding of the cheaper feeds to idle horses has 

 another decided advantage. Work horses are not expen- 



