CHAP. v. FOOD FOR WORKING ANIMALS. 993 



amount of water consumed by the animal is thus diminished. Maize 

 is apparently the most perfect type of a maintenance diet. 



"If work is demanded from the adult animal, the quantity of food 

 supplied must be increased in proportion to the amount of work 

 required, but the proportion of albuminoids in the food is not neces- 

 sarily to be raised. This fact has been but slowly recognised ; it is 

 confirmed, however, by a multitude of practical trials made both on 

 men and horses. In Wolff's recent experiments with horses, the 

 ratio of nitrogenous to non-nitrogenous substance in their diet was 

 diminished from 1 : 4'4 to 1 : 7*3, without &ny deterioration in the 

 labour value of the diet being apparent. 



" Work is performed by the energy obtained by the combustion of 

 organic matter in the muscle; it is indifferent whether this organic 

 matter be nitrogenous or non-nitrogenous. When an animal is doing 

 accustomed work, or in other words, is "in training," the daily waste 

 of muscle is no greater than when at rest. Severe unaccustomed 

 exertion is attended with an extra waste of nitrogenous matter. A 

 diet tolerably rich in albuminoids would thus be advisable during 

 training. 



" The comparative values of the different constituents of food already 

 given, express their relative capacity for the production of work. 

 Albumin has a slightly higher value than starch, their comparative 

 values being : 



Starch 100, Albumin 107. 



" The horse has only a small power of digesting vegetable fibre. 

 Foods like hay, and especially straw-chaff, are suitable only for a 

 maintenance diet, or light labour. For hard work, the hay and straw 

 must be diminished, and more digestible foods substituted, as oats, 

 maize, or beans. In choosing what grain shall be purchased for a 

 working horse, the farmer will be chiefly guided by its market price ; 

 the proportion of albuminoids present is sure to be sufficient. The 

 various horse foods must, however, be combined with judgment, as 

 some of them, as maize and bran, are more laxative than others. 



" We pass next to the milk-yielding animal. We have in this case a 

 daily production, in large quantity, of a liquid rich in albuminoid 

 matter ; with this condition there is frequently associated the produc- 

 tion of young. The supply of albuminoid matter in the food required 

 by a cow in full milk, if measured by the quantity of albuminoids in 

 the products yielded, is thus greater than that demanded by any other 

 animal on the farm. The products of the cow milk and calf have 

 all of them a high albuminoid ratio ; the albuminoid ratio of cow's 

 milk being 1 : 3'6, and that of a newly-born calf about 1 : 2. Every 

 condition thus points to the necessity of a high albuminoid ratio in 

 a diet suitable for a cow in full milk. The maintenance diet of a dry 

 cow may contain only a small proportion of albuminoids, and the 

 feeding is most economical when this is the case ; but when the cow is 

 in-calf, and still more when it is in full milk, the proportion of 

 albuminoids in the diet must be considerably raised if the animal is to 

 be properly sustained. 



3 s 



