26 THE ECONOMICS OF FEEDING HORSES 



of the wall. Further, moderate distention is necessary 

 for the stimulation of the mucous membrane to secrete 

 enough fluid to liquefy the ingesta. In rabbits fed upon 

 flour only, a kind of inflammation is set up by the stop- 

 page of the food in the intestine, and the animals 

 soon die. Similarly, horses fed on maize, a food con- 

 taining very little fibre, require some rough, hard hay — 

 such as timothy or cocksfoot — or even a little oat-straw, 

 for otherwise the intestines become filled with a pasty 

 or putty-like mass, which cannot be propelled along the 

 bowel, and colic and fatal impaction soon occur. It has 

 been estimated that whilst the capacity of the digestive 

 tract of the horse is about 46 gallons, that of the ox is 

 about 78 gallons, and these figures give some guidance 

 as to the relative bulk of food to be supplied to the two 

 animals. 



The attempt to determine what percentage of a food 

 is digested by an animal may be made in one of two 

 ways. Firstly, the method of artificial digestion may be 

 tried by submitting a finely ground sample of the food 

 to the action of the salivary, gastric, and pancreatic 

 juices respectively, in a glass vessel kept at the body 

 temperature. Digestion does, in fact, go on, and some 

 of the starches and proteins are converted into sugar 

 and peptone respectively, but the conditions are so 

 artificial that the results are quite inapplicable to an 

 animal. Again, as has been shown, there is a great 

 difference in the digestive powers of the horse and ox, so 

 far as crude fibre is concerned, and this is true, only 

 to a less degree, of the other constituents of food. In 

 other words, the digestibility of the same food is different 

 with different species of animal, and in each must be 

 determined separately. 



