904 The Feeding of Farm Stock. [feb., 



the food. For these purposes oils and carbohydrates are 

 absolutely valueless. Every ration, for any class of stock, 

 must therefore contain a certain amount of digestible albu- 

 minoids, the minimum amount requisite varying according to 

 the class of stock and the character and amount of the 

 "amides" and digestible carbohydrates by which the albu- 

 minoids are accompanied. 



For all other purposes digestible albuminoids, oils, and 

 carbohydrates are, to a great extent, mutually replaceable in 

 proportions that vary somewhat according to the use to which 

 the nutrient is put in the animal. Thus, for the production 

 of heat in the animal (and in general for maintenance pur- 

 poses) one pound of digested oil goes as far as 2J lbs. of 

 digested carbohydrates (starch or sugar), or nearly 2 lbs. of 

 digested albuminoids. For the production of animal fat, 

 or for the performance of mechanical labour (or for productive 

 purposes in general) the relative values of digestible oil and 

 carbohydrates remain much the same as for heat-production, 

 but the albuminoids are for these purposes slightly inferior, 

 or at most equal to carbohydrates. These relative values 

 may be summarised as follows : — 



Relative Values (Starch=i). 



Dig. Dig. Dig. 



Carbohydrate. Albuminoid. Oil. 



For maintenance ... I 1*25 2*4 



production 1 0*95 2*4 



As regards the digestible fibre of foods, for the production 

 of heat in the body this is practically equal to the more easily 

 dissolved carbohydrates; for the production of fat or mech- 

 anical energy, however, its value is largely dependent upon its 

 mechanical condition. If the fibre be very hard, tough, and 

 difficult to masticate, such nutriment as the animal extracts 

 from it will be mainly required to supply the energy necessary 

 to support the prolonged mastication, so that in this condition 

 it will be practically valueless even to the classes of stock 

 (ruminants, i.e., cattle and sheep) best adapted for dealing 

 with it. The more thoroughly it is reduced to a soft, easily 

 masticated condition, however, before being supplied to the 

 animal, the more nearly will it become equal to carbohydrates 

 for productive purposes also. 



From the foregoing it will be observed that albuminoids are 

 capable of fulfilling all the functions of food, whereas oils, 



