Spring is upon us once again! Hopefully, your pastures are greening up and you are able to get more riding in before the sun goes down. However, don't forget to limit feeding time on the new spring grass for horses that have been eating mostly hay all winter. Start with an hour on the pasture and work your way up to a full day over the course of a month or more to avoid grass diarrhea and possible laminitis. Horses that have been diagnosed as insulin resistant or Cushinoid should not have access to new spring grass at all. These horses should be kept off the pasture entirely or muzzled during turn-out until the grass dies back in the heat of the summer, usually July.

Everyone knows that you shouldn't look a gift horse in the mouth. And why not? Probably because you are likely to find that your gift horse is a bit older than the giver told you he was. Aging horses based on their teeth is not an exact science, and it can take years of experience to be competent. If aging the horse is of critical importance, please have your veterinarian do it for you. However, if you want to try to do it yourself, how would you? 

The easiest part of the horse's mouth to look at are the incisors, or front teeth. Horses have 12 incisors and up to 4 canine teeth, though geldings are more likely to have canines than mares. Just like people, horses first grow baby teeth, or deciduous teeth, then these teeth fall out and are replaced by a permanent set that the horse keeps throughout his life.

In foals, the deciduous incisors are often wider than they are tall. Foals get their first four incisors within the first week of life. These are the central four. The second four incisors erupt at approximately 4-6 weeks old, and the third set of four (the corners) erupt at 6-9 months old. Therefore, you can reliably estimate the age of a foal based not only on body size, but dentition.

As foals grow up, they begin to lose their deciduous incisors. In general, they replace the central set of incisors at 2.5 years, the middle set at 3.5 years, and the corner set at 4.5 years.  The permanent teeth tend to be more rectangular in shape and taller than they are wide. Especially when the permanent teeth are newly erupted, they have a very deep cup in the chewing surface called the infundibulum.

So, here is a quiz. How old are these horses?

Horse 1:

This horse is A) 6 months  B) 1.5 years  C) 2.5 years  D) 3.5 years

Horse 2:

This horse is A) 1 year B) 2 years  C) 3 years  D) 4 years

Horse 3:

This horse is A) 1 year B) 2 years  C) 3 years  D) 4 years

Horse 4:

This horse is A) 6 months  B) 2 years  C) 4 years  D) 6 years

Horse 5:

This horse is A) 3 days  B) 6 weeks  C) 9 months  D) really cute!