Page 42 - NMHBA Spring 2021

by Megan Petty, DVM
How often have you heard a friend or colleague talk about a horse that is “just a little thin?” Maybe you even have one of your own. Invariably there are steps people take when they think their horse doesn’t look as good
as it should. Usually, you will hear about the improvements they have made to combat this condition, often including deworming and an increase/change/modification to the diet of
the horse. When I have this conversation with someone, my very first question is/has been/ will always be, “When was the last time your horse had their teeth done?” The response is almost universally a pregnant pause. This pause happens for a variety of reasons. Sometimes it is to shake off the cobwebs and remember when just exactly that was. Sometimes it is to find a reason that it has been so long.
Sometimes, however, it is because the owner does not know the answer at all. Dentistry, also typically referred to as “floating,” is a supremely important aspect of horse husbandry that is often overlooked. Cost is occasionally a factor, as is the availability of a person willing and able to perform quality work. Yet, all too commonly
it is because people simply do not know it needs to be addressed.
Horses have hypsodont teeth, meaning they are constantly erupting and growing longer and taller as the horse ages. As the horse chews, the in-wear portion of the tooth is worn down, but never gets appreciably shorter due to this almost constant growth. However, due to their rotary chewing motion and the anatomy of the horse’s jaw, this cycle of grinding and growing creates a real issue for the horse. The top jaw, or maxilla, is wider than the lower jaw, the mandible.
This asymmetry causes the horse to develop sharp enamel points along the cheeks on the upper teeth, and also along the tongue on the lower teeth. These sharp points make chewing remarkably uncomfortable and can cause the horse to drop feed and sometimes be reluctant to eat at all due to the pain. We all know the purpose of teeth is to grind up food, but in truth the mouth and teeth are the first part of the digestive tract. Without a good way to break down large food particles in the mouth, the rest of digestion does not occur appropriately. This is especially true for the horse who is designed to eat a predominantly long-stem roughage diet.
Horse teeth fall into three broad categories: incisors, premolars, and molars; and in all,
the horse has anywhere between 36-44 teeth. The number disparity occurs due to the fact that some horses lack canine teeth and/or their 1st premolars more commonly referred to as “wolf teeth.” It is more typical to find wolf
teeth in male horses, and mares usually will not have canine teeth. Horses are born with deciduous premolar teeth already present, the exception being the wolf tooth that erupts
at approximately 5-6 months of age. Next to erupt are the first set of deciduous incisors at 6-8 days, followed by the second set at 6-8 weeks of age, and the third set at 6-8 months
of age. Deciduous teeth are baby teeth, or caps, which will be replaced as the horse grows with permanent teeth. When molars erupt, they do so without a baby tooth to precede them and they erupt in order starting at 1 year of age until around 4 years.
A common misconception I encounter is that the only horses who require dental attention are older horses. While it is true that older horses require special attention to their teeth, they aren’t the only ones who need their mouths addressed. Young horses also benefit from more frequent dental work due to the presence of
caps. Premolar caps are shed from front to back at approximately 2 years 6 months, 2 years 8 months, and 3 years 6 months of age. Permanent incisors erupt from inside to outside at 2.5, 3.5, and 4.5 years respectively. Usually, a cap breaks loose and falls out on its own as the permanent tooth below it erupts. But for our racing and performance horses, occasionally we have to expedite the process by pulling the caps. The loose cap is a perfect location for hay and grain to become lodged, and the roots as they loosen are sharp and can pinch the tongue, cheeks, or
The top jaw, or maxilla, is wider than the lower jaw, the mandible. This asymmetry causes the horse to develop sharp enamel points along the cheeks on the upper teeth, and along the tongue on the lower teeth.
40 New Mexico Horse Breeder
EQUINE DENTISTRY