Inside the horse's mouth

A ton of teeth

The adult male horse has up to 44 permanent teeth, and a mare may have between 36-40 permanent teeth. Like humans, horses get two sets of teeth in their lifetime. The baby teeth, also known as deciduous teeth, are temporary. By age five, most horses will have their full set of permanent teeth.

Why so many? Evolution has designed the horse's skull to accommodate greater quantities of high-fiber forage foods. The horse's Eocene ancestor stood a little over two feet tall. Modern equus are now almost triple that height and require 27 times more food! An amazing grinding system of the horse's teeth accommodates such an increase in food intake and processing.

Elongation of the head and neck allowed for continual pastural grazing; increasing the height and complexity of the tooth shape. The forward teeth, known as incisors, function to shear off forage. The cheek teeth, including the molars and premolars with their wide, flat, grooved surfaces, easily grind the feed to mash before it is swallowed.

Biting the basics

To help appreciate the horse's distinct eating process, let's follow the path of the food particle.

First, the food touches the lips. Sensitive upper and lower lips are the integral structures for feed apprehension. During grazing, the lips are drawn back to allow the incisor (front central teeth) to sever the grass at the base.

Once the food enters the mouth, the horse begins mastication, or chewing, of the food by grinding it. This occurs by moving the mandible, or jaw, in a side-to side chewing movement; not up and down.

Chewing takes place where the molars are aligned in the skull, also known as the "molar arcade." After several minutes of chewing, the food softens and is suitable for swallowing.

Picky, picky

Horses are selective eaters; they prefer grasses and legumes but a wide variety of shrubs, herb, woody plants and even roots may be selected. They tend to avoid eating grass in areas polluted with manure or horse urine.

The horse is a continuous grazer; that is, both confined horses in a stall and free-ranging animals usually eat 10-12 hours daily for 30-180 minute intervals if hay or pasture is available.

However, full confinement to a stall does affect eating behavior. Confined horses fed concentrate or pelleted feed eat more rapidly and spend the remaining time in boredom (i.e. standing, lying down, searching for food, chewing wood, etc.). Horses confined and not allowed access to pasture don't use incisor teeth for shearing and this may lead to incisor overgrowth.

This is where your equine veterinarian comes in. Many arbitrary practices such as training techniques and full boarding change natural functions in the horse's mouth. Dental problems can continually worsen unbeknownst to the owner or trainer. The horse may begin to resist the bit, not respond to common training techniques or even lose weight and the trainer may never consider that it may be a dental problem. From floating to filling, your practitioner can help you develop a dental hygiene program for your horse to help put "power steering" in your horse's mouth.

Floating

The techniques used to float teeth vary between practitioners. Some veterinarians will sedate the horse and use a full-mouth speculum to allow greater thoroughness in the examination and more precision in performing corrective procedures.

But floating teeth is just one of many procedures that may be available from your veterinarian. Many other dental problems can develop and go undetected until severe pain becomes obvious.

Recap on caps

Deciduous (baby) teeth all should be replaced by the age of five years. Sometimes, however, these teeth are not shed and cause a "retained cap." This condition can cause inadequate chewing, anorexia (loss of appetite) and poor performance.

Your veterinarian can extract the deciduous premolar or incisor once the boundary between the deciduous and permanent tooth is visible. If the baby tooth is extracted too early, though, the permanent tooth can be damaged.

Canines

As the name suggests, canine teeth are sharp, tall teeth used for tearing food. Canines are primarly found in the male horse and can become too tall and sharp; increasing the risk of laceration to other horses when playing, chance of injury by catching on fixed objects, and difficulty in inserting and removing the bit. A veterinarian can shorten tall and rasp sharp canine teeth to prevent these occurrences.

More than just a toothache

Just like you, your horse can have many other problems with his dental hygiene. Common ailments horses suffer include loose and/or broken teeth, excessively worn teeth, infected teeth and gums and even gum disease.

Identify problems

It is important to catch dental problems early. Waiting too long may increase the treatment needed or may even make remedy impossible.

If a horse starts behaving abnormally, dental problems should be considered as a potential cause. Horses with dental problems may show obvious signs, such as pain or irritation of the mouth. Other indications of dental problems include

• loss of feed from mouth while eating
• difficulty chewing or excess salivation
• loss of body condition
• large, undigested food particles in manure
• head tilting or tossing, bit chewing, tongue lolling, fighting the bit or resisting the bridle
• bucking or failing to stop or turn
• foul odor from mouth or nostrils
• traces of blood in mouth
• nasal discharge or swelling of the face

Other horses may show no noticeable signs because they simply adapt to their discomfort. For this reason, have your veterinarian thoroughly examine and float your horse's teeth at least once a year. This dental exam provides the opportunity to perform routine preventative dental maintenance and avoid having relatively minor problems become serious in the future. The end result is a healthier, more comfortable horse.