ESTIMATING THE AGE BY THEIR TEETH 51 



that the foods fed them have a marked influence on the 

 wear of the teeth, thus making differences which are not 

 solely due to age. Liberal feeding which favors early ma- 

 turity is also likely to affect the appearance and arrival of 

 the incisors. 



86. Appearance of Incisors. The difference in the ap- 

 pearance of the milk teeth or temporary incisors and the 

 permanent incisors is readily understood after they have 

 been once inspected. The temporary incisors are slender, 

 narrow and constricted at the neck and very white, while 

 the permanent incisors are broader, thicker and usually of 

 a light yellowish tinge. 



87. Order of Appearance of Incisors. The permanent 

 incisors of both the upper and the lower jaws appear at 

 the same time so that it is only necessary to refer to the 

 upper. There are six permanent incisors in each jaw in 

 the full mouth and these make their appearance in pairs 

 about as follows: The pair in the center are the first to 

 appear and they have displaced the temporary pair and are 

 full grown when the colt is from 2 l / 2 to 3 years old. The 

 second pair or the two next to these are fully grown at 

 3!/2 to 4 years and the third pair have displaced the two 

 corner temporary incisors at 4% to 5 years of age. At 

 this time the horse usually has a full mouth. 



88. Disappearance of the Tables. The best indications 

 of the age from five to ten years is the order of the disap- 

 pearance of the tables or marks in the incisors. At five 

 years the tables in the central pair of incisors of the lower 

 jaw show some wear but it is not until the horse is about 

 six years old that they have almost disappeared. At seven 

 years of age the " swallow-tail' ' as it is called, or the nick 

 in the corner incisor appears. At this age also, the two 

 incisors next to the central pair lose almost all traces of 

 their tables through wear, and at eight years the corner 

 incisors or outside pair are so worn as to be almost free 

 from any appearance of having tables. At nine years of 

 age the tables have disappeared from the central pair of 



