Telling an older horses age using Galvaynes Groove   QUESTION:  How do you tell the age of an older horse, say over 10 years old that has no registration papers and comes from an auction so you don't know anything about it?  My Vet says there is no way because the grinding surface of the tooth wears differently depending on what the horse has ate it's whole life?   ANSWER:  Yes there is a way to tell the age pretty close on horses over 10 years old regardless of what they have ate, diet, horse dentistry done, etc. Although just an estimate, it is fairly accurate within 1 to 2 years.    By using "Galvayne's Groove" on the Upper Corner Incisor.  At 10 years old, this distinctive groove first appears, at 15 years old, it is 1/2 way down the tooth, at 20 years old it has reached the bottom of the tooth.  It then begins to slowly disappear from the top of the tooth where it first appeared.  By 25 years old it has disappeared from the top 1/2 of the tooth. By 25 years old, the teeth are completely finished erupting from the gums, thus age is difficult to tell accurately after 25 years old. They say that by 30 years old, the groove is completely gone, having disappeared now from the bottom half of the tooth also, but have only read Galvayne's Groove on horses accurately up to 25 years old.