The Animal Body — Digestion — Metabolism. 33 



habit or custom. When corn silage is first placed before cows, not 

 infrequently, after sniffing it, they will let it alone for a time. They 

 then usually begin nibbling at it, and later will gorge themselves 

 thereon if permitted. In such cases food that at first seems un- 

 palatable suddenly becomes palatable. 



In his early experience the author was feeding two lots of fat- 

 tening steers, one on shelled corn and wheat bran, the other on 

 wheat bran and shelled corn ground to a meal. After some weeks 

 of successful feeding, the rations for the two lots were reversed. 

 The steers changed from corn meal to whole corn showed a strong- 

 dislike for the new ration, eating so little at first that they shrank 

 materially in weight. From this the general conclusion might have 

 been drawn that shelled corn is less palatable than corn meal for 

 fattening steers. But the steers given corn meal in place of shelled 

 corn were equally dissatisfied. No conclusion is possible from this 

 experiment except that custom and habit— something entirely ex- 

 traneous to the food— are possible factors in palatability. 



While palatability has a bearing on digestibility, the reverse is 

 not necessarily true, for humans and animals often show fondness 

 for kinds of food that are indigestible or worse. Even poisonous 

 substances may be palatable, and, per contra, food which the human 

 or animal does not relish or even dislikes may have high nutritive 

 value provided the repugnance is overcome. 



Despite the complexities of the subject, every practical stockman 

 knows that to get the best results he must at all times provide feed 

 for his animals which is palatable and altogether acceptable. This 

 may be accomplished in considerable degree by steadily using the 

 same feeds and feed combinations, and in always avoiding sudden 

 and violent changes in their character and in the manner of feeding. 



III. Metabolism. 



In the preceding division we learned how digestion prepares the 

 nutrients of feeding stuffs for the nurture of the animal body. In 

 what follows there is briefly set forth how the digested materials 

 are brought into the body proper and what becomes of them. Chem- 

 ists and physiologists, working together with skill and great pa- 

 tience, have been able quite fully to set forth and explain the pro- 

 cesses of digestion. When the nutrients leave the alimentary tract 

 and enter the body, the difficulties of following them and learning 

 what becomes of them have in a large measure thus far exceeded 

 4 



