EGUS Series Part 3: Management of the horse with Equine Gastric Ulcer Syndrome (EGUS)

So, we now know how to recognize horses afflicted with EGUS and also the proven therapeutic methods used to treat such horses.  This begs the question, how do we manage these ulcer patients?   Numerous studies have shown that intense training and competition schedules, frequent shipping, high concentrate (starch) diets, decreased availability of pasture and insufficient ingestion of hay are all common contributing factors to the development of EGUS.  Our goals as veterinary professionals are multifaceted and include neutralization of acid, promotion of mucosal repair, and the improvement of management processes. 

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Knowing that the equine stomach produces 1.5L of acidic stomach juices on an hourly basis, we can already begin to recognize the benefits of having a constant input of hay into the horse’s GI tract. Additionally, if your horse can handle some alfalfa in his diet, there are several benefits to ingesting this leafy legume.  When compared to timothy, brome and orchard grass, alfalfa is higher in calcium and protein, both of which act as literal chemical buffers to stomach acid.  Additionally, if we consider that alfalfa often has a coarser texture, this means the horse is required to take more chews before swallowing the feed.  As the horse masticates, he produces saliva.  This gooey substance is high in bicarbonate, a chemically basic molecule which also aids in the neutralization of stomach acid.  If your horse is an easy keeper or has some metabolic/nutritional restrictions, high quality straw can also be incorporated into the horse’s forage regime to provide valuable roughage without adding starch or calories.  

Why do we avoid diets high in starch?  As starch is broken down in the stomach, it is fermented by the resident bacteria into volatile fatty acids and lactic acids, all of which contribute to the already acidic environment of the stomach.  If your horse is in an intensive training program and consuming large amounts of grain, breaking the total volume of grain into multiple small feedings throughout the day will help to reduce the amount of acid produced at the time of ingestion.  Additionally, fats can be substituted for starches in the form of rice bran, bean meal, and oils as a means to provide calories without the detrimental by-products of starch fermentation. 

In addition to the continuous ingestion of fiber products, care should also be taken to reduce the stresses of competition and travel.  For those equine athletes where the stresses of competition are unavoidable, the use of PPIs or H2 blockers to prevent the development of gastric ulcers is highly recommended.  Finally, while there is no direct link today between the use of probiotics and the prevention of gastric ulcers, such products may be helpful in maintaining hindgut health in stressed equines. 

Other ulcer-inducing risk factors in an equine life may include aggressive pasture/stall mates, lack of turnout, consistent loud noises, persistent radios, systemic illness, chronic pain, long term use of NSAIDs (bute, banamine, etc), intensive breeding programs and routine training on an empty stomach. 

In conclusion, EGUS is a clinical condition requiring both medical and long term nutritional management.  The continuous ingestion of fiber products is by far one of the most important aspects to managing a horse with clinical signs of ulcers, and in achieving long term optimal GI health.

EGUS Series Part 2: Common (Proven) Treatment Methods of horses with Equine Gastric Ulcer Syndrome (EGUS)

Let’s say you’ve just indulged in a rich gourmet meal complete with red wine and a decadent chocolate dessert.  An hour or so later, you’re regretting that decision as some pesky heartburn keeps you awake.  Eventually you swallow some Tums©, Tagamet©, Zantac© or even Nexium© and breathe a sigh of relief as those clinical signs abate and you drift off to sleep.  Believe it or not, many of the medications we use to treat our own heartburn work on horses as well.  The goal of EGUS therapy is not to treat the ulcer itself, but to decrease the acidity of the horse’s stomach to allow its natural healing mechanisms the opportunity to repair the damaged mucosal lining.

The gold standard in the treatment of EGUS is omeprazole, sold under the trade name Gastroguard©.  This product stops the production of gastric acid at the immediate source, and is known in the chemical world as a proton pump inhibitor (PPIs).  By stopping the production of gastric acid, the mucosal lining of the stomach is allowed to heal, which can take anywhere from a couple days to multiple weeks, depending upon the size, severity and location of the ulcer within the stomach.  UlcerGuard© is another omeprazole product, given at a quarter of the dose of Gastroguard©, and utilized in the prevention of gastric ulcers.  Both of these products are given once a day, and elicit the best response when given in the morning on an empty stomach.  They are most effective in the first eight hours after administration.  It must be noted that long term use of PPIs has been shown to impair the digestion of protein, an integral component to a horse’s nutritional demands.  PPIs are safe for use up to 90 days (so your 4 weeks of omeprazole therapy is perfectly safe) but relying on them for longer periods of time is not recommended. 

Ranitidine (Zantac©) and cimetidine (Tagamet©) have also been used routinely in the prevention and treatment of gastric ulcers.  Both drugs are considered H2 receptor antagonists, or H2 blockers.  Where omeprazole prevents the production of gastric acid directly at the source, H2 blockers are one step removed from that process and prevent the H2 signaling molecule (histamine) from binding to the receptor which activates the production of gastric acid.  Sounds complicated, right?  My goal in providing readers with such information is not to overwhelm you, but instead, to illustrate why veterinarians consistently turn to omeprazole when faced with EGUS; it halts the production of acid at the source and has a longer duration of efficacy compared to H2 blockers.  Sometimes, though, weeks of omeprazole therapy are not a viable, financial option for clients, so we may turn to the H2 blockers to help try to achieve similar results in the reduction of clinical signs of EGUS.  For the best efficacy, H2-blockers must be given three times a day, making them slightly more challenging from a management perspective.

Sucralfate is another product occasionally used as a protective agent in horses with ulcers located in the glandular region of the stomach.  When exposed to such acidic environments, this fluid is converted into a sticky substance which coats the lining of the stomach and binds to preexisting ulcerations to form a protective barrier.  This product must be given on an empty stomach (which we try to avoid in horses with EGUS) and may prevent the uptake of other drugs administered simultaneously.  While effective, the size of the dosage and the duration of therapeutic programs often makes this product cost prohibitive. 

A phenomenon which must be mentioned in this discussion is that of rebound acid hypersecretion.  Long term use of PPIs followed by abrupt discontinuation of therapy has been shown to cause a consistent increase in gastric acid production, often worse than the initial stomach condition.  When using PPIs, it is important to wean the horse off of medication using progressively lower doses over the course of 10 days.  There are several studies demonstrating the beneficial effects of using sea buckthorn in the prevention of rebound acid hypersecretion. 

Stay tuned for Part 3 of Dr. Hartman’s blog regarding the management of horses with EGUS!