If you are a horse owner or equine professional, it is very likely that you have been concerned about stomach ulcers at some point. It is estimated that 60-90% of performance horses have some degree of equine gastric ulcer syndrome (EGUS). The clinical signs and treatment are widely understood, however there is quite a bit of misinformation that is passed along. Thorough discussion with your veterinarian about any concerns for EGUS is imperative to accurate diagnosis and treatment.
Why do horses get ulcers?
The equine stomach is composed of two different types of tissue: glandular and non-glandular. The glandular portion encompasses the bottom two thirds of the stomach and is responsible for secretions such as hydrochloric acid (HCl) that help to digest food. Mother Nature aptly built in great protective mechanisms for this part of the stomach, so that it doesn’t injure itself just by doing its job! However, the top one third of the stomach isn’t so lucky. It is in this non-glandular portion that 80% of gastric ulcers are found, presumably from contact with unbuffered acid. To add insult to injury, horses secrete acid continually, which means this area is exposed to acid at all times.
Who is at risk?
It is common knowledge that stress is a large contributor to ulcers, though this is difficult to define. Some horses may be affected by small management changes, such as stall neighbors or turnout times, and others may not seem to mind. More proven risks of gastric ulcers include training, transport, stall confinement, intermittent feeding, high grain diets, and use of non-steroidal anti-inflammatory drugs (phenylbutazone and flunixin). All these factors expose the non-glandular portion of the stomach to acid through movement, lack of hay or saliva buffers, or increased concentration of acid products.
Does my horse have ulcers?
There are many equine behaviors that get quickly attributed to ulcers, especially if one or more of the above risk factors is present. In fact, ulcers were identified in up to 92% of horses in whom an owner reported conditions or behaviors commonly associated with ulcers. The most common clinical signs associated with ulcers in adult horses include poor performance, decreased appetite, intermittent colic of varying degrees, poor body condition, attitude changes, inadequate energy, and chronic diarrhea.
This list of symptoms is not unique to gastric ulcers and could just as easily be a partial list of signs for several other ailments. The only way to truly diagnose EGUS is with gastroscopy, a procedure performed by a veterinarian that allows visualization of the inside of the stomach. This procedure is done under standing sedation and is typically complete within 30 minutes. Thoroughly examining the interior of the stomach allows a complete understanding of the presence or absence of ulcers, and their severity and location. The ultimate outcome of this exam is appropriate management both for treatment, as well as prevention. Unfortunately, at this time, there is no reliable laboratory test (blood or feces) that will diagnose EGUS.
It is not uncommon to assume the presence of ulcers based on clinical signs and attempt treatment, interpreting a positive response to treatment as proof of the diagnosis. This approach, while not unacceptable, ultimately puts the horse at risk for inappropriate treatment as severity and location of ulcers is not known. Additionally, it does not allow for follow up exams to ensure complete resolution, and potentially can delay treatment of a disease other than ulcers.
How are ulcers treated?
Treatment of EGUS may be one of the most questioned topics in equine medicine, primarily due to cost and owner experience. There are two primary groups of drugs that have been used and evaluated for the treatment of ulcers: those that coat the stomach, and those that manipulate acid production.
There is only one FDA approved medication for the treatment of EGUS: GastroGard (omeprazole), at a dose of 4mg/kg orally once per day. The length of treatment has traditionally been 28 days, based on research showing the best healing at that point, compared to 14 and 21 days. One study demonstrated up to 86% of ulcers to be completely healed after four weeks of medication.
GastroGard is the only drug and dose that has been extensively tested for efficacy and safety by the FDA. Each tube of medication reliably has the same amount of omeprazole as every other tube, ensuring proper dosing. The patented paste formulation has been proven to deliver omeprazole to the small intestine intact, where it gets absorbed. Any drug that is not FDA approved for this reason cannot make the same claims.
Does this mean no other medication or supplement will work? No. It means that there is a lack of scientific proof that other drugs can treat ulcers at all. It also means that the exact dose to use for ulcer treatment is unknown. From your horse’s viewpoint, it means that time and money very well may be wasted using cheaper medications that might not work.
In addition to treatment with GastroGard, management changes are crucial to both elimination and prevention of EGUS. As saliva is an excellent buffer of acid, it is recommended that horses have hay or pasture available at all times. High concentrate feeds should be fed at the minimum volume necessary for calories and should always be fed with hay or pasture. Alfalfa hay has excellent buffering capabilities as well, and can be offered if appropriate, considering other aspects of the horse’s health. Turnout as much as possible, and elimination of stressful situations should be attempted.
What is your recommendation?
As with all other equine health concerns, it is best to open a discussion with your veterinarian. My personal recommendation, in situations where ulcers are suspected, is an initial gastroscopy to evaluate the degree and severity of ulcers. If they are present, GastroGard is recommended at a 4mg/kg daily dose. A recheck gastroscopy at 14 days is ideal and may determine the appropriateness of decreasing the dose of medication. A final gastroscopy at 28 days, prior to discontinuing GastroGard is strongly recommended.
In addition to management changes, omeprazole (GastroGard or UlcerGard) may be used for prevention of ulcers at a lower dose around times of high risk.
Kristi Gran, DVM, DACVIM