THE FEEDING OF FARM STOCK. 7 < "i 7 



food depend upon the amount of ash. Some of the salts — like common salt 

 — have a definite physiological action, and, though not properly foodstuffs, 

 arc essential to a proper digestion of foodstuffs. The amount of this 

 mineral, or saline matter, is not taken into account in estimating the feed- 

 ing value of a plant, for though small in amount it is always present in 

 sufficient quantity to supply the requirements of the animal. 



Fibre is that part of the plant which is unattacked by acids or alkalies. 

 It is practically cellulose. It cannot be regarded as digestible, for although 

 it disappears to some extent in the body of the animal, especially with grass 

 and herb-eating animals, it is not broken down in the way that t lie diges- 

 tible carbohydrates are attacked (see these), but is decomposed in such a 

 way as not to produce heat, arid its assimilation is probably unattended by 

 much benefit to the animal. It has no feeding-value. Its presence is, how- 

 ever, essential, as it gives bulk to the food, and mechanically stimulates the 

 walls of the alimentary canal, promoting healthy digestion. Too much 

 fibre, however, makes the food too bulky, so that the animal cannot eat 

 sufficient of it to get the necessary amount of nourishment. It also makes 

 the food unpalatable. Of these constituents the only one possessing direct 

 feeding-value is the mineral matter or saline matter, and this, though 

 always small in amount, is present in sufficient quantity in all fodders, and 

 in estimating the feeding-value of a plant as food we do not usuallv take 

 it into account. Water and fibre, it will be seen, are not direct foods, but 

 give succulence and bulk, and exercise a physiological action. 



The ingredients of direct feeding-value are the following: — 



Albuminoids. — These are distinguished from the others by the fact that 

 they are the substances which contain nitrogen. They are composed of 

 carbon, hydrogen, oxygen, and nitrogen. The flesh and blood of animals is 

 made up of nitrogenous material, dry blood or meat containing about 16 

 per cent, nitrogen as do also substances like hair, wool, horns, hoofs, &c. 

 It will thus be seen that the amount of albuminoids in the food is a point 

 of the highest importance since these are the only source of nitrogen avail- 

 able to the animal. The albuminoids are, therefore, often called " flesh 

 formers " or " muscle formers." Their chief function is to produce the 

 nitrogenous material of the body, and to some extent the fat, and to main- 

 tain it, replacing the daily waste of the tissues. By their combustion within 

 the body, heat and mechanical force are also developed. 



Carbohydrates. — This is the name given to a large class of organic com- 

 pounds found in plants, the principal of which are the starches and sugars. 

 The carbohydrates are composed of carbon, hydrogen, and oxygen only, 

 without nitrogen. Their consumption, therefore, does not add to the nitro- 

 genous substances of the body nor repair the waste. Their function is the 

 production of heat and mechanical energy by their combustion within the 

 body. They are often called " heat-producers,", because they maintain the 

 temperature of the animal. The process of their combustion consists in 

 combining with oxygen, and being split up into carbonic acid and water, 

 a process identical with that of the burning of fuel. They also partially 

 assist in the production of fat, especially when consumed in excess of 

 immediate requirements. 



Fats and Oils. — The function of these substances is much the same as 

 that of carbohydrates. They also are composed of carbon, hydrogen, arw* 

 oxygen, but contain proportionately much less oxygen, and consequently 

 much more carbon and hydrogen, than the carbohydrates. They are on 



