Things You'll Need
- Halter
- Lead rope
Instructions
Place a halter on your horse. Restrain it in cross ties or tie it by the lead rope in its stall.
Raise the horse's upper lip so that you have a clear view of one of its upper-corner incisors -- the teeth immediately to the right or the left of the two central upper-front teeth.
Note the appearance of the darkened groove running through the middle of the tooth. If there's no noticeable line, the horse is likely less than 10 years old.
Observe the beginnings of the furrow at the gum line somewhere around age 9 or 10. It grows down the outer surface of the tooth as the horse ages.
Notice when the groove approaches the bottom of the tooth. By the time the horse has reached the age of 15, the groove should be halfway down the incisor. Galvayne's groove reaches the bottom of the tooth by the time the horse is 20 years of age.
Detect when the line begins to recede from the gum line, down the surface of the tooth. This typically begins at age 20, with the groove moving down from the gum to the bottom of the tooth as the animal ages, until age 30, when Galvayne's groove disappears entirely.