STATICS 135 



For these reasons, therefore, it is customary to allow the 

 following quantities of digestible protein in the maintenance 

 rations of animals. 1 



For oxen and horses, about f Ib. per 1000 Ibs. live weight, 

 per day; and for sheep about 15 Ibs. per 1000 Ibs. live weight 

 per day. 



Sheep require larger quantities of protein than cattle or 

 horses in proportion to their weight, because of the production 

 of the wool. Wool is a nitrogenous substance formed from 

 the protein of the food, and its growth is not arrested even 

 when the animals are in a state of practical starvation. 



Feeding Standards. The attempt to reduce the food 

 requirements of animals to formulae, such as that given on 

 p. 128, is something of an innovation. The older and generally 

 accepted method is to state the amounts of digestible nutrients 

 required by animals per 1000 Ibs. live weight irrespective of 

 their actual size. Such a statement is called a "feeding 

 standard." For example, according to Wolff, the feeding 

 standard for the maintenance of oxen is as follows : 



DIGESTIBLE NUTRIENTS REQUIRED PER 1000 LBS. LIVE WEIGHT 



PER DAY, 



Protein. Fat. Carbohydrates. 



Ibs. Ibs. . Ibs. 



075 0-15 8-0 17-5 



The statement that oxen of 1000 Ibs. live weight require 

 for maintenance a daily quantity of food which yields 35 kt. 

 'of available energy and a certain amount of protein, is also 

 a feeding standard. In fact, it is the same feeding standard 

 expressed in different terms. This may be proved in either 

 of two ways as follows : 



1 N.B. The digestible protein of the maintenance ration undergoes 

 oxidation like other constituents of the food, and the heat produced helps 

 to maintain the temperature of the animal's body. A part of the 35 kt., 

 or whatever the amount maybe that is required for maintenance, is derived 

 from the oxidation of the protein ; the latter is not, therefore, an addition, 

 but is included in the former. In calculating rations it is important to 

 see that the amount of food which gives the required thermic value also 

 contains the required amount of digestible protein. 



