44 AGE OF THE DOMESTIC ANIMALS. 



supposed to be born on the 1st of May, while thoroughbreds 

 are supposed to be born on January 1st, and each dates its age 

 accordingly. We may, therefore, have horses which officially 

 have the same age vary from each other in their real age by 

 some months. 



Races which develop slowly, a debilitated temperament, and 

 an impoverished nourishment, all tend to retard the eruption of 

 the teeth, while, on the contrary, precocious races, strong feeding, 

 etc., hasten the appearance of the full mouth. Gestation in the 

 young mare retards the eruption of her teeth, especially of the 

 corner teeth, which mark the five years. In cold, damp climates 

 the teeth are several months later in appearing than they are 

 in warmer and dryer climates. The thoroughbred and all 

 improved horses develop their full mouths earlier than their less 

 well-bred relations. Exceptions may occur in both extremes. 

 A rising three-year-old has been known to have all of its per- 

 manent incisors, and more frequently a six- or seven-year-old is 

 seen with its corner milk-teeth. 



ERUPTION OF THE TUSKS. 



The appearance of the tusks is so variable that it is of little 

 value as an indication of age. They are usually absent in the 

 mare, and in the horse or gelding may be out at three years, or 

 may not pierce the gums until the animal has had all of its 

 other permanent teeth. The lower tusks frequently appear 

 almost a year in advance of the upper ones. They usually appear 

 at about the same time as the corner incisors. 



ERUPTION OF THE MOLARS. 



As the young horse becomes older the deciduous molars 

 become worn down until they only exist as thin plates which 

 cap the crowns of the first three molars of permanent dentition 

 and are but loosely held in their alveola. They become broken, 

 and the sharp points wound the neighboring cheek, causing 

 difficulty of mastication, which can frequently be relieved by 

 removal of the loosened teeth. 



The two first molars of first dentition are through the 



