How to Tell a Horse's Age by Its Teeth
Many people think that you can tell a horse's age by its teeth. This isn't quite true. Horse's teeth aren't like the rings of a tree that show each year's growth. Telling a horse's age by its teeth is not 100 percent accurate, but it will give you an approximate range if you don't know the horse's actual date of birth. The younger the horse, the closer the teeth will match its real age. As horses age, many factors can affect the condition of the teeth and make it more difficult to estimate age. Things like basic maintenance, diet, grazing conditions, vices, and genetics all play a role in how the horse's teeth themselves are aging.
Baby Horse Teeth
Foals get their first milk or deciduous teeth shortly after birth. The final milk teeth are grown in by the time the foal is about nine months
old. The first permanent teeth begin to grow in when the horse is between two and three years old. It's not unusual for a horse owner to find a shed tooth in a feeder or on the ground. The milk teeth are shed gradually, and all of the permanent teeth are grown in by around age five. Milk teeth are paler in color and shorter than permanent teeth.
Adult Horse Teeth
The eruption times of the upper central incisor (2.5 years), upper middle incisor (3.5 years) and upper corner incisor (4.5 years) for horses under 5 years of age is considered fairly accurate in determining a horses age. 1
The new permanent teeth are quite concave on their surfaces and these "cups" along with the angle, shape and a groove on the outer vertical