APPENDIX II 361 



PRINCIPLES OF FEEDING 



The various substances found in animal bodies may, for con- 

 venience, be grouped under four heads: water, ash or mineral 

 matter, fat, and nitrogenous matter or protein. These sub- 

 stances occur in the animal body in somewhat varying propor- 

 tions, depending upon age, condition, treatment, etc. 



Water is an essential constituent of the animal body and con- 

 stitutes from 40 to 60 per cent of its live weight. Ash occurs 

 mainly in the bones and constitutes from 2 to 5 per cent of 

 the live weight. The fat occurs in greatly varying proportions, 

 but rarely is less than 6 or more than 30 per cent. All 

 those substances containing nitrogen are classed as protein. 

 They constitute an important group, oi which washed lean meat 

 and the white of egg may be taken as types. They contain about 

 16 per cent of the element nitrogen and are the only class into 

 the composition of which this element enters. All the working 

 machinery of the body, such as flesh, skin, bones, hair, internal 

 organs, brain and nerves, contain a large proportion of protein. 



COMPOSITION OF FOOD MATERIALS 



The same four groups of substances found in animal bodies, 

 viz. : water, ash, fat and protein, are also found in the food they 

 consume and, in addition, the food of herbivorous animals contains 

 a class called carbohydrates. 



Water. All foodstuffs, no matter how dry they may seem, 

 contain a considerable amount of water. In grains and dried 

 fodders it ranges from 8 to 15 per cent of the material, in green 

 forage and silage it is about 80 per cent, while in some roots it 

 amounts to 90 per cent. While water is essential to animal life 

 and the water in the food fulfils the same function as that drunk 

 by the animal, we do not value food materials for the water they 

 contain, and computations are based upon the water-free or dry 

 matter. 



Ash. When a foodstuff is burned till the organic matter is all 

 driven off, the residue is the ash. It is composed largely of lime, 



