DETERMINING THE AGE OF ANIMALS 



191 



indicate. In order to stand severe work the animal must be 

 able to masticate the feed, and prepare it for digestion in the 

 stomach and intestines. The degree of wear on the molar 

 teeth may be indicated by the wear on the incisors. The general 

 condition of the horse and his ability to stand hard work depend 

 very largely on the condition of the table surfaces of the molars. 



It is very difficult to judge the age of horses that have de- 

 formed mouths or that are in the habit of crib-biting, because 

 of the irregularity in the wear of the incisors. 



When examining the teeth for the purpose of determining 



Fig. 54. — Transverse section of incisor tooth: (A) peripheral cement; (B) peripheral 

 enamel; (C) ivory; (D) central enamel; and (E) central cement. (After Huidekoper.) 



the horse's age, the shape of the incisors, the angle with which 

 they meet and the appearance of their table surfaces should be 

 observed. The teeth of young horses show more or less yellowish 

 cement. At about seven years of age the anterior faces of the 

 teeth are usually white, later a yellowish color. The teeth of 

 middle-aged horses may be long, and in aged animals, narrow 

 and short. The incisors meet at a more acute angle in old than 

 young horses. 



The free portion of the incisor tooth is flattened from l^eipre 

 to behind. At the level of the gums its two diameters are about 

 the same, but the portion of the tooth imbedded in the jaw bone 



