Solipeds 12 12 12 4 24
Ox 8 12 8 0 24
Sheep 8 12 8 0 24
Hog 12 12 12 4 24
The tusks or canine teeth are not always present in the female. Ruminants do not have upper incisor teeth. The temporary teeth are erupted either before or within a few days to a few months after birth. The eruption of the permanent teeth and the replacement of the temporary teeth occur at different periods up to the age of four and one-half years (Fig. 53). It is well to keep the following table of dentition in mind when examining the mouths of animals for the purpose of determining their age.[1]
Horses Cattle Hogs
Teeth Temporary Permanent Temporary Permanent Temporary Permanent
Incisors: yrs. mos. yrs. mos. mos.
Centrals At birth 2 6 At birth 1 8 At birth, 12
or 3-4
weeks
First 4-6 wks. 3 6 At birth 2 9 8-12 wks. 18
laterals
Second 5-12 days 3 6
laterals
Corners 6-9 mos. 4 6 12-18 days 4 6 At birth 9
Molars:
First At birth 2 6 At birth 2 6 7 weeks 5
Second At birth 2 6 At birth 1 6 8-28 days 14
Third At birth 3 6 At birth 3 8-28 days 13
Fourth 10-12 1 6 13
Fifth 2 2 5
Sixth 4-5 2 6 9
Seventh 18
Canines or 4-5 9
tusks
IN DETERMINING THE AGE of the different domestic animals by the development and appearance of the teeth, most of the attention is given to the lower incisor teeth. Up to the fifth year, the age of the horse or ox can be easily determined by the eruption and replacement of the incisors.
At one year of age the colt has a fully developed set of temporary incisors. The ruminant's incisors at this age all show wear.
The two-year-old colt shows a well-worn set of incisor teeth, and the ruminant at this age has replaced the nippers or centrals.
The third, fourth and fifth years are indicated by the replacement of the temporary nippers, dividers and corners in the horse, and the first and second dividers and corner teeth in ruminants.
[Illustration: FIG. 52.—Longitudinal section of incisor tooth: cup; cement; enamel; ivory; and pulp cavity.]
In the horse the permanent nippers are full grown and in wear at three years of age; the permanent dividers are full grown and in wear at four years of age; and the permanent corners are full grown and in wear at five years of age. The table surfaces of the incisor teeth of a five-year-old horse show different degrees of wear. At this period in the animal's age, the nippers have been in wear two years, the dividers one year, and the corners are beginning to show wear. In ruminants, all of the chisel-shaped table surfaces of the incisors show considerable wear when the animal is five years old.