“Don’t look a gift horse in the mouth.” We are all familiar with this old adage instructing us to be gracious for what we receive, no matter its monetary value. However, most of us have not stopped to think about exactly why the condition of the horse’s mouth has a direct relationship to its “value”. A valuable horse is a healthy horse; its dental health has a profound impact upon the animal’s overall condition and vitality. Nutrition provides the building blocks for life, growth, and protection from illness. Despite an abundant supply of quality feed and pasture, dental disease may interfere with the delivery of nutrition into the body, leaving the horse susceptible to many other health problems.
Primary teeth (aka baby teeth, milk teeth, or deciduous teeth) are usually shed by the age of five, and replaced by 36 to 44 permanent teeth depending upon the sex and breed of the horse. The forward most teeth are called the incisors. They are used for cutting grass during grazing, opposing each other in the upper and lower jaws like the blades of scissors. Directly behind the incisors are the canine teeth. These are sharply pointed “fangs” used only during male sparring, and are rarely present or significantly underdeveloped in females. Wolf teeth may come next, after a natural gap in the tooth distribution along the jawbone. Wolf teeth are vestigial structures that are no longer used by modern horses. They are present in less than a third of all horses, male and female. The rearmost teeth in the horse’s dental anatomy are the premolars and molars, also called cheek teeth. These are used for thoroughly grinding and pulverizing (masticating) food before swallowing. Proper mastication is necessary to derive all of the essential nutrients from plants. Food that is not chewed sufficiently passes through the digestive tract unutilized. A horse’s teeth continue to erupt or grow out of necessity, in order to compensate for the huge amount of wear that takes place in consuming abrasive plant material.
Problems affecting the teeth are many times a result of modern horse husbandry practices, despite the best intentions by owners. Wild equines had to pick through many tougher stalks in unmanaged savannahs to get to tender, more desirable shoots. These plants contain a higher silica content which is abrasive to tooth enamel. The rate of tooth wear was much higher than for today’s horses kept in lush pastures of fine, soft grasses. Wild equines had (and still have) shorter life spans as a result of rapid tooth “wear-out”, but today’s domesticated horses are more prone to tooth overgrowth and subsequent dental disease which can compromise their extended life expectancy despite better overall provisions and care.
Horses fed processed diets may have more abnormalities with their cheek teeth. These abnormalities can be sharp points that arise due to abnormal wear because of less chewing action during mastication. These edges may cause ulceration of the cheek and tongue, which causes pain and may lead to infection.
Horse anatomy also plays a role in premolar and molar wear patterns. The lower jaw is narrower than the upper, which correlates with a 15 degree angle (approximately) of the cheek teeth.
Canine teeth in stallions can grow tall and sharp, posing an increased risk of severe injury and fight-wound abscesses in other animals during sparring. They are not used for mastication whatsoever and do not wear down much naturally. Overgrown canines may cause difficulty when placing and removing the bit during bridling. Wolf teeth may interfere with proper bit placement as well and are often removed if present.
Symptoms associated with dental problems are vast and not always easily recognized as originating in the mouth. Furthermore, horses try to conceal pain in an effort to avoid the attention of predators. Therefore, oral health is always examined regularly and if the animal shows any signs of illness.
Mouth discomfort can lead to improper mastication and swallowing of large food particles that may not be processed fully in the GI tract. This can lead to colic, weight-loss, and malnutrition derived diseases. Occasionally, severe dental problems can lead to a condition called choke, where a large bolus of un-chewed food becomes lodged in the esophagus. Symptoms more obviously related to dental pain include head tossing, fighting the bit, unruly riding behavior, unilateral nasal discharge and odor or blood from the mouth. A simple change in behavior however, may be the only evidence of oral health problems.
A thorough dental exam should be performed by the veterinarian at least once a year, and more often for problematic horses. The doctor will float the teeth – a process involving sedation and filing of any overgrown or irregularly worn teeth – and inspect the oral cavity for signs of infection or disease. The idea of floating is to create a symmetrical profile of the upper and lower teeth to cause them to wear more evenly. In addition, retained primary teeth, that are a source of infection and odor, will be removed when needed.
It is clear that the horse’s mouth is directly linked to its overall health, performance, and potentially its lifespan. Regular preventive measures and minor wear corrections are far easier to deal with than established and secondary complications of poor dental health.