32 SCIENTIFIC FEEDING OF ANIMALS 



what the latter does. When it comes to the 

 different varieties of grass, the horse is found to 

 digest only 20-25% less nitrogen-free extract 

 and crude fibre than does the sheep. With clover 

 hay, or lucerne hay the differences are again less, 

 being at most 10%, whilst the digestibility of the 

 grains is about equal for each class of animal, 

 except as regards the crude fat. 



The pig digests coarse fodders considerably 

 worse than does the horse. Only 23 % of the organic 

 matter of wheat chaff is digested by the pig, whereas 

 the ox digests 36%. These differences, which are 

 clearly shown in Table II of the Appendix, hold also 

 for the digestion of green fodder. With oil cakes 

 and grains these differences are less pronounced, 

 and practically vanish with such foods as mangels 

 and potatoes. There are, however, many by- 

 products, such as dried brewers' grains and various 

 other refuse materials from the brewery and dis- 

 tillery, which the pig digests very badly. 



All these differences are mainly due to the kind 

 of digestive apparatus possessed by the animal, for 

 in function, length, and capacity there are consider- 

 able variations in the different species. The action 

 of the digestive fluids and of the bacteria upon the 

 food is also subject to variations and alters the 

 conditions very materially. 



2. Different breeds of the same species of animal 

 possess an equal digestive power. Investigations 



