12 



The Purchase of Feeding Stuffs 



comes cellulose. Carbohydrates comprise the bulk of the 

 feeding material in cereal grains, hay y straw, and roots, and 

 in these foods they must be looked upon as the chief ingre- 

 dients of value. In oil cakes, pulse grains, dried grains, and 

 malt dust, the feeding value is derived to a large extent from 

 albuminoids and fats. The chief function of the carbo- 

 hydrates is to supply heat and energy, and when fed in large 

 quantity they are also capable of producing animal fat. 



Fat and Oil. 



The fats and oils are extremely potent heat-producers, and, 

 weight for weight, are nearly 2 \ times as valuable for this 

 purpose as the carbohydrates. It has, in fact, been found by 

 experiment that a pound of pure fat can produce as much 

 heat as about 2 \ pounds of pure starch or sugar. When 

 sufficient heat-forming food has been consumed to maintain 

 the temperature of* the body, fats and oils may be largely 

 stored up as fat in the body of the animal consuming them, 

 and so increase its weight. Linseed, linseed cake, and decor- 

 ticated cotton cake are the foods richest in fat, after which 

 come dried grains, undecorticated cotton cake, oats, and maize. 



Fibre. 



Fibre consists mainly of cellulose, and though, under 

 certain circumstances, it may be so affected in the animal's 

 body as to have some feeding value, its importance in this 

 respect is not great. 



Mineral Matter. 

 Mineral matter, although performing an indispensable 

 function in animal nutrition, may be neglected in arranging 

 diets for mature animals, as it is usually present in sufficient 

 quantity in all foods. This constituent of food is of more 

 importance in arranging diets for young, growing animals. 



Comparative values of Foods. 

 Manures can be valued, conveniently and reliably, by 

 taking the number of units of the manurial element or ele- 

 ments that they contain, and multiplying by the market value 

 per unit of such elements. (See Journal, Vol. VIII, No, 4, or 

 Leaflet No. 72.) Although this system of valuation cannot 



