64 



THE SHEPHERD'S MANUAL. 



COMPARATIVE NUTRITIVE VALUES OP GRAINS AND GRAIN 

 PRODUCTS. 



The analyses here given, however, are but an obscure guide as 

 regards the comparative values of the different substances for pro- 

 ducing fat. It is very important to arrive at a clear idea of this 

 in feeding sheep, because the quality of the wool depends greatly 

 upon the secretion of a requisite amount of yolk which consists in 

 great part of oil and a matter approaching in character to wax, 

 to say nothing of the desirability of rapidly producing fat. The 

 fat-forming elements in any article of food consist of starch, sugar, 

 gum, oil, and fat, all carbonaceous matters, or matters rich in car- 

 bon, with the addition of certain proportions of hydrogen and 

 oxygen. The chemical composition of these elements is very sim- 

 ilar, and in some of them is nearly identical. Thus an animal fed 

 upon starch or sugar, may become fat, and it is well known that 

 bees fed upon sugar are able to produce either honey or wax from 

 this food. In the processes of digestion and assimilation, starch, 

 sugar, and gum, are changed to fat. This fat is either consumed 

 in the process of respiration, or is stored up in the tissues of the 

 body, and increases the weight of the carcass. But in the con- 

 sumption of food rich hi starch, a much larger portion is necessary 

 to produce a given weight of fat, or a given result in the process 

 of respiration, than is required of a food rich in fat or oil. The 

 relative values of fat or oil, and starch, as nutritive elements, is as 

 one of the former to two and a half, nearly, of the latter, or exact- 

 ly, as 10 is to 24 ; that is, 10 Ibs. of oil or fat will go as far in pro- 

 ducing fat or in maintaining respiration, and the natural heat of 



