WHAT HAPPENS TO FOOD 17 



undergo various changes before they can be utilized by the 

 animal. Some of this material is not made use of at all but 

 passes off as waste. 



What Happens to the Food. — Food, taken into the 

 mouth, is chewed and mixed with a secreted liquid known 

 as saliva. These processes are known as mastication and 

 insalivation. The food is then passed into a long tortuous 

 tube known as the digestive tract. In this tract it is broken 

 down into simpler substances so that it may be absorbed. 

 This breaking-down process is known as digestion. The 

 process of taking the broken-down and dissolved food 

 materials through the walls of the digestive tract is known 

 as absorption. Transporting the materials to the different 

 parts of the body and using them for the different purposes 

 required is known as assimilation. 



The digestive tract of all farm animals consists of a long 

 and a very crooked tube distended in certain parts for the 

 storage of food. The canal is divided into the following 

 parts : 



1. The gullet, extending from the mouth to the stomach, 



2. The stomach, 



3. The small intestine, which is divided into the duo- 

 denum, the jejunum, and the ileum, and extending from 

 the stomach to the large intestine, and 



4. The large intestine. 



In the case of the cow and sheep, which are called ruminat- 

 ing animals, the gullet is expanded into three large recep- 

 tacles in which the coarser rough foods are placed partially 

 chewed by the animal. They remain here for a while, and 

 later are returned to the mouth and rechewed. This process 

 is known as rumination. The horse has a small stomach, 

 but eats large quantities of hay. In the case of the horse, 



T. AND L. ANIM.AL HUSB. 2 



