by Alex Bianco, MS, DVM
University of Minnesota
While the relationships between humans and their domestic pets are varied and complex, the connection between horse and owner is unique in that it often spans years to decades. While the horse has a prolonged lifespan, often 20 to 30 years, in nature this lifespan is limited by the degenerative changes that accompany advanced age. With advancements in veterinary medicine and the shift of the horse’s role in society from beast of burden to a valued companion, more horses are reaching geriatric age (>20 years). To promote healthy longevity, early recognition and treatment of the special needs of geriatric horses are important tasks for both you and your veterinarian.
There are three major components to caring for the geriatric horse: dental care, management of osteoarthritis, and management of pars pituitary intermedia dysfunction (PPID). This is the first of three articles that will cover each of these aspects of geriatric horse care in detail. Most horse owners understand that adult horses have premolars and molars (“cheek teeth”) that continuously erupt over their lifetime. However, the entire adult premolar/molar is fully formed within the bones of the jaw (maxilla and mandible) and only a portion of the tooth is visible (picture an iceberg). This unerupted tooth is called the “reserve crown” and may be up to 4 inches long. Starting in their late teenage years/early 20’s, a horse may start to run out of reserve crown on any given tooth. This tooth may be called “expired” to signify that the horse has not lost the tooth but it has simply run out of reserve crown.
Aside from the natural expiration of teeth, geriatric horses are also prone to dental disease that can result in teeth falling out or being extracted by a veterinarian. Because each set of premolars and molars erupts at a different age, they also expire at different ages. These can lead to gaps between teeth (diastemas) and teeth of varying heights (“wave mouth”) which causes abnormal chewing patterns and uneven wear on the teeth. These variations in dentition, combined with the rough nature of forage and the natural bacterial population of the mouth, can lead to secondary infections of the teeth below the gum line, at the tooth root. Bacterial tooth root infections typically result in loose, and/or fractured teeth. If the tooth is an upper molar, the infection may also spread in to the maxillary sinus and cause a secondary bacterial sinusitis.
While dental infections rarely lead to systemic disease, dental abnormalities or tooth root infections often result in ineffective or painful chewing which results in decreased feed intake, weight loss, and increased risk of esophageal obstruction (“choke”). Key facts for dental care of your geriatric horse include signs of dental disease, oral examinations, dental floating (occlusal equilibration), and nutrition. Signs of equine dental disease include dropping feed, malodorous or bad breath, nasal discharge, and/or weight loss. If these signs are observed, schedule an oral exam as soon as possible as these may be signs of dental disease. Geriatric horses should have an oral exam every 6 months. A sedated oral exam using an oral speculum should be utilized at least once a year as it is the only way to properly evaluate for fractured or loose teeth, especially molars. Prior to being a teenager, your horse may only need their teeth floated every 1 to 2 years. While they may be “routine” floats, establishing a preventative dental care program will help your horse transition in to old age.
A dental float should be performed by a veterinarian at least once a year once horses reach geriatric age. This is the best way to identify dental abnormalities prior to the development of secondary complications. Only a veterinarian should be used for dental care, as only a veterinarian is trained to (and legally allowed to) appropriately sedate your horse and properly diagnose and treat disease. The more missing or expired teeth a horse has, the more difficult it will be for the horse to sustain their body weight on hay alone.
The development of complete pelleted feeds have revolutionized our ability to maintain geriatric horses that cannot get what they need from hay alone. Your veterinarian may recommend that a complete pelleted feed be your horse’s primary diet, with or without supplemental hay. Your veterinarian may recommend a fat supplement to provide additional calories if your horse still has difficulty maintaining their weight. An equine nutritionist should work with your veterinarian if weight loss becomes an issue for a geriatric horse.