Equine Gastric Ulcer Syndrome


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ulcerDid you know that the symptoms of stomach ulcers in horses can be so subtle and nonspecific that they are easy to miss? Did you know that ulcers can affect any horse, regardless of use or age? The term “equine gastric ulcer syndrome,” or EGUS, is used to describe ulcerations of the end of the esophagus, the stomach, and the beginning of the small intestine. Gastric ulcers can be caused by many factors and are one of the most common ailments suffered by horses today.

Gastric ulcers have an estimated prevalence in 50% to 90% of adult horses. These ulcers occur most frequently in horses that perform some sort of physical activity such as racehorses (90%), endurance horses (70%) and show horses (60%). However, even recreational horses and foals can suffer from EGUS.

Does My Horse Have EGUS?

The symptoms of EGUS can be very subtle and vague, oftentimes presenting themselves in a slight attitude change, a reluctance to train or a decrease in performance. In fact, the majority of horses with gastric ulcers will not show any specific clinical signs but will often show more subtle indicators such as:

* Poor appetite

*Poor body condition

* Dullness

* Poor hair coat

* Weight loss

* Excessive time spent lying down

* Low grade colic

* Loose feces

* Teeth grinding

* Sensitivity to touch of the belly/flanks

The only way to definitively diagnose gastric ulcers in horses is through gastric endoscopy. This involves placing an endoscope into the stomach and examining the tissue surface for irritation and lesions.   Scoping can be used to determine the presence of gastric ulcers, and it can be used after treatment to determine if ulcers have healed adequately for treatment to be discontinued.   Some owners choose to treat their horses for gastric ulcers without endoscopy and simply look for a change in clinical behavior. While this can be helpful, the only way to truly know if treatment can be discontinued is to scope the horse to ensure that all ulcers have healed.

Why Is EGUS So Prevalent?

The main reason why horses are so susceptible to gastric ulcers is due to their stomach anatomy. First, the horse’s stomach is much smaller compared to other animal species, so it cannot handle large amounts of food at once. Horses are built to eat small, frequent portions of feed over extended periods of time. Because of the natural grazing situation of continuous intake a horse evolved in, a horse’s stomach constantly produces a steady stream of acid to digest the continuous feed intake.   A horse’s stomach produces acid 24 hours a day, 7 days a week. This can amount to up to 9 gallons of acidic fluid per day, even when the horse is not eating!

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In a natural environment, this stomach acid is buffered by the continual intake of grass and forage. However, in today’s environment where horses are fed in two to three larger meals a day, the stomach is subjected to long periods of time with no feed to neutralize the acid. If there is no feed present in the stomach for the acid to work on, it will begin to eat at the stomach lining itself.

In addition to stomach anatomy, the types of feed we incorporate into our horse’s diets today can increase the risk for EGUS. Diets high in non-structural carbohydrates, like sugar and starch, greatly increase ulcer risk because these diets produce volatile fatty acids upon digestion. These volatile fatty acids can contribute to ulcer development.

There are several other factors that can contribute to a high risk of ulcer development in horses.Stomachs_Blog Physical and environmental stressors, such as transport stress, stall confinement, and lack of exposure to other horses, can increase a horse’s risk for EGUS. In addition, chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) such as Bute or Banamine can increase the risk of EGUS. Lastly, exercise and training can greatly increase the prevalence of EGUS, as exercise increases the production of gastric acid. Also, many horses are exercised on an empty stomach, which gives the sensitive stomach tissue no protection against this increased stomach acid.

EGUS Prevention and Treatment

While a veterinarian can recommend the best medical treatments to address EGUS, there are several feeding and management practices that can prevent and manage the occurrence of gastric ulcers.

  • Allow horses free choice access to forage, whether it be hay or grass. Allowing the horse to graze on some type of forage on a continuous basis helps buffer stomach acid.
  • Horses with a history of EGUS can benefit from a small amount of alfalfa added to the diet. Alfalfa has a buffering effect on stomach acid and has been shown to reduce the incidence of EGUS in horses. Many times, one flake of alfalfa per day added to the diet is enough to make a difference.
  • Mix a small amount of chopped hay into your horse’s grain meals. Adding chopped hay causes the horse to chew more, which creates more saliva production. Saliva is an excellent stomach acid buffer.
  • Reduce the amount of sugar and starch in the horse’s diet to control volatile fatty acid production.
  • Maximize turnout out for ulcer affected horses. If these horses must be stalled, allow them to have access to see and socialize with other horses to reduce stress.
  • Do not exercise a horse on a completely empty stomach.
  • Avoid or decrease the use of NSAIDs, or consider alternatives if necessary.

Take Home Message

While EGUS is extremely common in today’s horse population, and most of our horses experience at least one strong risk factor for the disease, an ounce of prevention goes a long way in reducing the chances that our horses will ever suffer from gastric ulcers. Many times, making just a few small dietary or management changes is enough to keep our horses healthy and comfortable for years to come.   It’s important to remember that not all horses are the same, so it’s up to the horse owner to determine which recommended approach works best for their specific horses. If you have any questions about managing your ulcer prone horse, it’s always best to consult with a certified equine nutritionist and your veterinarian to create an individualized program that maximizes your horse’s comfort and health.

Beth Stelzleni, M.S., PAS
Seminole Feed®