RELATION OF FOOD TO ANIMAL REQUIREMENTS. 107 



•unwashed fleece ; but in the case of ordinary sheep, freely 

 exposed to weather, the quantity may be 15 per cent., or 

 less. In a washed fleece the fat may vary from more than 

 30 per cent, to 8 per cent., or less. Short fine wool con- 

 tains the largest proportion of fat. Pure wool hair con- 

 tains about 16 per cent, of nitrogen. The quantity of 

 nitrogen and ash constituents in unwashed wool has been 

 already given on jDage 63. 



The production of wool-hair and of wool-fat is practi- 

 cally no greater when sheep receive a liberal fattening 

 diet, than when the diet only suffices to maintain the 

 ordinary condition of the animal; indeed, under poor 

 treatment, the carcase may lose weight to some extent 

 without the production of wool being seriously altered. 

 With starvation, however, the yield of wool is considerably 

 diminished. If sheep are kept on a poor diet for the 

 mere production of wool, the amount of albuminoids sup- 

 plied must not fall too low, wool-hair being formed entirely 

 from this part of the food. 



Production of Milk. — The quantity of milk produced 

 is largely determined by the individual character of the 

 animal, and on the length of time which has elapsed since 

 birth ; the quality of the milk is also affected, though to- 

 a less extent, by the same conditions. Subject to these 

 natural limitations, both quantity and quality are greatly 

 influenced by the character of the food supplied. 



A liberal diet is essential for a full supply of milk. 

 Green fodder is favourable to a large produce, so also are 

 brewers' grains. The diet of a milking cow should vary 

 with the yield of milk, the object being to obtain as large 

 a yield as can be reached without fattening the animal. 



