460 FEEDING ANIMALS. 



be plain why this animal produces a larger growth from 

 the same amount of food than the ox or sheep. Messrs. 

 Lawes and Gilbert's researches throw some light upon this 

 point. They found, by accurate experiment, that the 

 stomach and its contents amounted, in the pig, to only 1M 

 per cent, of the whole weight of the animal, whilst in sheep 

 it was 7K per cent., and in oxen UK per cent, of the entire 

 weight. But the proportion of the weight of the intestines 

 and their contents is greatest in the pig, it being in that 

 animal 6K per cent., while in the sheep it is 3K, and 

 in oxen only 2% per cent. See on this point page 63 

 ante. 



The food of the ruminant consists of a large proportion 

 of indigestible woody fibre, whilst the food of the pig con- 

 sists more largely of starch, and the digestion of its food 

 takes place largely in the intestinal canal. This explains why 

 the pig is so great a digester of food, and why it consumes 

 more food in proportion to the weight of its body than 

 the ox. It also furnishes the basis for an explanation of the 

 fact that the pig gains more in weight from a given amount 

 of food than the ox. As we have seen, all animals require a 

 certain amount of food to keep them alive, or in their present 

 condition, called the food of support, and it is the food eaten 

 and assimilated beyond this food of support that gives the 

 increase, and this is called the food of production. This extra 

 food all goes to increase the weight. Now if the pig digests 

 and assimilates more in proportion to its weight than the 

 ox or sheep, it must use a larger precentage of what it eats 

 as the food of production, and, of course, a larger gain re- 

 sults from a given quantity of food. Large capacity for 

 digestion is, therefore, a prime quality in animals reared for 

 the production of meat, and in this respect the pig stands 

 unrivaled among all our domestic animals. We shall there- 

 fore be justified in studying carefully all its wants with a 

 view of supplying them. 



