106 The Feeding of Animals 



The incisors or front teeth are those which are used 

 for prehension, and by grazing animals for cutting off 

 the grass and other herbages. With the ox, sheep and 

 goat, incisors are found only in the lower jaw. These 

 shut against a tough pad on the upper jaw. They are 

 constantly wearing off, and with old animals may be so 

 worn away as to leave only the roots. Such animals 

 do not graze successfully. With the horse and pig, in- 

 cisors are found in equal numbers in both jaws. 



The molars are the grinding teeth. Those of the 

 horse sometimes need filing on the outside edges in 

 order to prevent irritation and soreness of the adjacent 

 tissues. A diseased molar may occasion an animal 

 much discomfort and cause imperfect mastication. 



During mastication there is poured into the mouth 

 a liquid called the saliva, which has two important 

 functions: (1) it moistens the food, and (2) with sev- 

 eral species of animals it causes a chemical change in 

 certain of the constituents of the food. 



The saliva has its origin in several secretory glands 

 that are adjacent to the mouth cavity, and from these 

 this liquid is poured into the mouth through ducts that 

 open in the cheek and under the tongue. The chief of 

 these glands are located in the side of the face, below 

 and somewhat back of the jaws and beneath the tongue, 

 and are called the parotid, the submaxillary and the 



