7«'» THE FARMERS' HANDBOOK. 



this account a much more concentrated form of fuel, and their combustion 

 produces a greater amount of heat and energy than does that of starch or 

 sugar. 



The following summarises roughly the part played by each of these 

 ingredients in the nourishment of the animal : — 



Mineral matter supplies bone-material and inorganic salts. 



Albuminoids supply flesh and all nitrogenous material, replace waste 

 of tissue, supply to a lesser degree heat and energy and fat. 



Soluble Carbohydrates and Fat supply heat and muscular energy; also 

 fat when taken in excess. The heat-producing power of fat is very much 

 greater than that of carbohydrates, being about 2i times that of starch. 



Cellulose, even when assimilated, is of little value as a heat-producer, as 

 it is not split up into carbonic acid and water like starch, sugar, fat, &c. 



Nutr'ent Value of Foods. 



In calculating, for the sake of comparison, the nutrient values of different 

 fodders, the percentages of albuminoids, soluble carbohydrates and fat are 

 6imply added together, the fat being multiplied by 2| to reduce it to its 

 " starch equivalent." 



Albuminoid Ratio. — This is a matter of the first importance in the com- 

 pounding of a properly balanced ration, and is obtained by taking the 

 percentage of carbohydrates, adding to it 2| times the percentage of fat, 

 and dividing the sum by the percentage of albuminoids. This ratio of 

 albuminoid or nitrogenous substance to the non-nitrogenous constituents 

 in the food differs considerably in different classes of food. 



Thus lucerne hay contains one part of nitrogenous material to about 

 three and a half of non-nitrogenous. This is an example of a relatively 

 nitrogenous food, and the ratio is said to be a " narrow " one. In the case 

 of straw on the other hand there are twelve to thirteen parts of non- 

 nitrogenous material to every one part of nitrogenous material. This is an 

 example of what is known as a " wide " ratio, and represents a food poor in 

 nitrogenous constituents. Foods such as oil cakes, &c, have a still higher 

 nitrogen content (a much narrower albuminoid ratio) than lucerne hay. 

 Thus decorticated cotton cake contains about one part of nitrogenous matter 

 to one and a half non-nitrogenous, or has an albuminoid ratio of one to 

 one and a half. 



This albuminoid ratio is of the greatest importance in the choice of 

 rations for different animals, for the ratio which gives the best results 

 varies considerably with different animals, and also with the same animal 

 at different stages of its growth and according to the purpose for which it 

 is fed. Thus, for dairy-cattle a more nitrogenous food is required than 

 for cattle fed for fattening purposes, a narrow ratio being found to increase 

 the yield of milk, though feeding appears to have little influence on the 

 nature of the milk. 



Horses doing heavy work also require a greater proportion of nitrogenous 

 material than those doing only light work. 



Growing animals require, as a rule, a larger proportion of nitrogenous 

 material and a larger total quantity of nutritive material than do mature 

 animals, though they require less bulk in their food. 



It is, therefore, evident that the selection of a properly balanced food, a 

 food containing the correct proportions of nitrogenous to non-nitrogenous 

 constituents, is a matter of the first importance, and depends upon the 

 nature and age of the animal and the work which it is to do. 



