Article and Photos by Juliette Beauchamp. This article appeared in our July/August 2016 Issue

020low-resUlcers in horses are very common but they can be tricky to diagnose as there are a wide range of symptoms. With multiple factors that can influence a horse’s risk of developing ulcers, it takes a team effort to address and treat the problem. Horses may develop both gastric and/or colonic ulcers, although gastric ulcers are more commonly diagnosed.

The horse’s digestive system is a complex structure, sensitive to minute changes in diet and environment. Horses’ stomachs are comparatively smaller (about the size of a pumpkin) than the stomachs of other species, designed for frequent, small meals. This makes sense for a prey animal, as they are able to constantly forage and graze while remaining alert to any threats. Their stomachs produce large amounts of acid in preparation for continual grazing, and this is where a lot of problems arise with modern horses and how they are managed. For many horses, full-time turnout and grazing as nature intended is not possible, and instead they are given two or three large grain meals per day. This means they spend a lot of time with an empty stomach that is still continually producing acid- up to nine gallons per day, compared to about half a gallon produced by the average human.

The horse’s stomach is made up of two regions, with the top portion of the stomach being the squamous region and the bottom region made up of glandular mucosa. The bottom, glandular region is where the acid is produced, as well as the protective mucus. When gastric ulcers are seen, they are generally in the top, squamous region.

Stress, either due to a demanding show schedule, a prolonged period of stall rest, or a long trip in the trailer can also lead to the formation of gastric ulcers. Some studies have demonstrated that ulcers can form after just a few hours in a trailer. NSAID’s such as phenylbutazone, (“Bute”), and flunixin meglumine (Banamine) can increase a horse’s chance of developing ulcers by decreasing the stomachs’ mucus lining and thus decreasing the natural protection from the acid. Hind-gut ulcers and gastric ulcers found on the glandular region of the stomach are often due to chronic or overuse of NSAID’s.

Gastric ulcers are very common in horses, with some studies suggesting an 80-90% frequency among racehorses, and up to 60% in show horses. While some horses may show serious clinical signs, such as recurring colic or dramatic weight loss, the majority have much subtler symptoms such as generalized poor condition and coat health, loss of appetite, or a decrease in performance. Some may even appear completely healthy.

Gastric ulcers are also seen in foals, and tend to be more serious. Increased recumbency in foals can be a sign of ulcers. Photo by Juliette Beauchamp

Gastric ulcers are also seen in foals, and tend to be more serious. Increased recumbency in foals can be a sign of ulcers. Photo by Juliette Beauchamp

Gastric ulcers are also seen in foals, and tend to be more serious. Clinical signs in foals may include bruxism (grinding of teeth), diarrhea, lack of appetite, and frequent recumbency. Foals with ulcers will often lie on their backs in an attempt to avoid the pain. Interestingly, gastric ulcers were first discovered to be a serious problem in foals in the 1960’s, when they were seen on post-mortem exams and thought to be the result of eating rocks. By the mid-1980’s, it was well-recognized that foals could develop painful ulceration; this was also about the time that a long enough endoscope was developed for diagnosing gastric ulcers in mature horses.

Ulcers can only be diagnosed through gastric endoscopy (gastroscopy), which allows the veterinarian to visualize the stomach’s surface. Prior to gastroscopy, horses are fasted for 12 hours and lightly sedated. The endoscope is inserted through the horse’s nostril and into the stomach via the esophagus. This method allows for a clear diagnosis and treatment plan, although many simply treat suspected ulcers and allow improvement in behavior and health to be the diagnosis. This is a more cost-effective plan, but without gastroscopy it is impossible to truly know if there is ulceration and how severe it may be.

There is currently only one treatment for equine gastric ulcers approved by the FDA. Omeprazole (brand name GastroGard and UlcerGard) is a paste which is given for one month after diagnosis. After the month-long treatment, the horse should be scoped again to ensure healing of ulcers. To avoid recurrence of ulcers, some veterinarians recommend giving a single preventative dose of omeprazole during transport or competition. To prevent ulcers, it is best if horses can have as much turnout and free grazing time as possible, and to be sure they have companionship if they must be stalled. Feeding alfalfa hay or cubes can also be helpful as the alfalfa buffers acid production, and it is recommended to decrease grain rations (which produce volatile fatty acids and can lead to an increase in ulcers). There are also many supplements and feed additives on the market that claim to aid in preventing ulcers.

Horses can also develop colonic (or hindgut) ulcers. This condition occurs less frequently than gastric ulcers, but has similar symptoms. Horses often have mild colitis or intermittent colic symptoms followed by weeks or months of no clinical signs. Stress and chronic use of NSAID’s are the main risk factors for hindgut ulcers, with competition horses being most likely to develop them. Chronic ulceration of the colon is commonly referred to as Right Dorsal Colitis (RDC), and often gets worse as time goes on. Horses can develop both gastric and colonic ulcers; ultrasound of the right dorsal colon may help reveal the thickening of the colon wall indicative of hindgut ulcers.

Treatment of colonic ulcers consists of minimizing NSAID use and reducing bulk feed to allow the colon to rest and heal. Many horses are transitioned to a complete feed or alfalfa based feed so bulky, fibrous hay may be reduced. Psyllium (the fibrous seed husks from Plantago plant species, commonly used as a laxative) is often added to the diet as a lubricant and to increase intestinal water content. While medications used for gastric ulcers will not address colonic ulcers, sometimes antacids such as sucralfate are used to form a sort of bandage over the ulcer bed and promote healing.

Due to stresses involved in most horses’ daily routines, ulcers are very common. Fortunately many horse owners now are aware of the risk factors and best management practices to reduce them. A recent survey posted on a popular Virginia equestrian social media site resulted in a surprising number of responses from horse owners, all of whom had at some point treated horses for ulcers (with and without gastroscopic diagnosis). The most common treatment was omeprazole following endoscopic diagnosis, although some also treated suspected ulceration with ranitidine (Zantac) with good success. There were also some all-natural methods used, including papaya juice and even aloe vera juice infused with a medical marijuana tincture.

For Victoria Henderson, of Chesterfield, Virginia, it just made sense to spend the extra money for a definitive diagnosis after struggling to put weight on her recently purchased retired racehorse. Henderson’s vet scoped her gelding, Tonic, in April and discovered multiple gastric ulcers. The recommended treatment was GastroGard, one tube daily for 28 days. During the month-long treatment, Tonic’s appetite returned and he began gaining weight. Along with the GastroGard, Tonic was also transitioned to a high-fiber Senior feed as well as alfalfa hay and pellets, and turnout time was increased. A second endoscopy thirty days later revealed that all ulceration has healed, although there is still some scaring.