HISTORY OF HEREFORD CATTLE 



303 



the incisors and a few points of the molars are 

 uncovered. 



"The advance of the teeth and the receding 

 of the gums proceed very rapidly after birth, 

 and at the age of one month the temporary 

 teeth, viz., eight incisors in the lower jaw and 

 three molars in each side in the top and bottom 

 jaws, are fully developed. 



"No accurate opinion of the age of a calf can 

 be formed from the observation of the state of 



dentition between 

 the ages of one and 

 six months, when 

 the fourth molar is 

 cut; but during 

 this period the 

 jaws expand, the 

 incisor teeth grad- 

 ually become less 

 crowded, and the 

 space between the 

 third molar and 

 the angle of the 

 jaw increases as 

 the fourth molar, 

 which is the first 

 advances to occupy its 



FIG. 6. CALF'S TEETH AT 11 

 MONTHS. 



tooth, 



permanent 

 space. 



"At the age of six months the fourth molar 

 is well developed, but it is in close contact with 

 the angle of the jaw, and the posterior sur- 

 face is not quite free from the covering of the 

 gum. 



"Between six and twelve months old there 

 are no important dental changes, the incisor 

 teeth become worn, and as the jaws increase in 

 size there is more space left between them, but 

 it is not possible to assert from the state of the 

 incisor teeth whether an animal is under or 

 over the age of one year. (Fig. 7.) 



"Shortly after one year the fifth molar be- 

 gins to make its appearance, and at fifteen 

 -months it is well up. The appearance which 

 the fifth molar presents at this age is very much 

 like that of the fourth molar at the age of six 

 months. The new tooth is in close contact with 

 the angle of the jaw, and the gum covers the 

 extreme posterior part of its surface. 



"No change occurs in the incisors, except that 

 which is caused by the wear of the teeth and 

 the growth of the jaw, until the age of one 

 year and eight or nine months, at which time 

 the two central teeth are loose, and the first 

 broad teeth sometimes begin to project through 

 the gum. In very forward animals the central 

 permanent incisors are cut at the age of a year 

 and seven months, but they are never level with 

 the other incisors before one year and ten 



months, and their perfect development is in- 

 dicative of the age of two years. 



"The illustration (Fig. 10) was taken from 

 a Shorthorn heifer at the age of one year and 

 ten months, and may be accepted as indicative 

 of the general appearance of the incisors at 

 that age. 



"While the first pair of permanent incisors 

 are advancing to take the place of the tem- 

 porary teeth, the sixth and last permanent 

 molars push their way through the gum, and at 

 the age of two years are in position. Any error 

 of opinion as to the age which might arise from 

 the premature cutting of the central permanent 

 incisors may be corrected by reference to the 

 state of the molars. 



"The sixth molar takes the position de- 

 scribed, and the first and second permanent 

 molars take the places of the temporary teeth; 

 this change, in my experience, does not usually 

 occur until the animal is a month or two over 

 two years of age. 



"From two years and three months to two 

 years and six months the second pair of broad 

 teeth the middle permanent incisors occupy 

 the place of the corresponding temporary teeth 

 in all the cultivated breeds. Instances of late 

 dentition present themselves from time to time 

 in which the middle permanent incisors are not 

 cut until the animal is approaching three years 

 old. There is consequently a possible variation 

 of six months in the time of the appearance of 

 these teeth. 



"In the illustration (Fig. 12) the ordinary 



.IT 210 



FIG. 7. YEARLING'S TEETH AT 12 MONTHS. 



condition of the incisor at two years and six 

 months is shown. 



"It must be understood in reference to the 

 appearance of the second pair of broad teeth 

 that an expert, looking at a mouth which cor- 

 responds to the drawings, will conclude that the 

 animal is two years and a half old, but if he is 

 required to certify that the age is under or 

 above that period he must proceed to inspect 

 the molar teeth, and take into account the ani- 



