The age of a horse is determined by examining the teeth, a practice known as dental aging. Many factors affect a horse’s teeth as they wear down and develop. The most accurate way to determine a horse’s age is by studying the biting surface of the incisors.
The incisors are the front teeth that horses use to chop grass. Horses ages are usually estimated by the number and length of their incisors as well as the development of landmarks on the biting surface. These include cups, marks and stars. There is also a feature called Galvayne’s groove that appears on the upper incisors and can be used to estimate a horse’s age by observing its progression down the tooth.
An equine practitioner can perform a comprehensive oral exam of a horse to diagnose and treat a wide range of dental conditions, including abscesses, fractured teeth, and other serious problems that may require advanced dental care or extraction. The best time to do this is while a horse is calm and standing in a clean environment.
When a horse’s teeth are in their correct position, they are usually straight and evenly spaced. However, as a horse grows older, the incisors may become slightly longer and the angle at which they meet may change. This is why it’s important to schedule regular veterinary checkups to ensure that a horse’s teeth are healthy and in good shape.
A foal’s milk (deciduous) teeth will erupt and then begin to be replaced by permanent adult teeth, which are complete at 5 years of age. This is a critical stage in a young animal’s life, as it is during this time that the horse’s diet will have an impact on its growth and development.
To see the aging process, peel back the horse’s lips and examine the incisors. The incisors are the two central pairs both above and below, sometimes referred to as pincers or nippers. The four teeth that are next to these are known as intermediates and the outer teeth are called corners.
Observe the chewing surface of the incisors to see if there is a brown line (cup) or a round brown mark (star). Cups disappear from the bottom central incisors at 6 years of age, the intermediates at 8 years and the corners at 9 years of age. The back surface of the incisors are oval, becoming triangular in appearance at 15 years of age and then more rounded at 20 years of age.
Lastly, look at the biting surface of the incisors. A young animal’s teeth will be broad and flat and meet at a vertical line, while an older horse’s teeth will slope and are considered “long in the tooth.” This sloping angle is attributed to age and to the amount of wear that has occurred on the incisors. During this sloping period, teeth are more likely to get displaced or damaged. Keeping up with routine veterinary exams will help to prevent these problems from occurring.