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. 

Photo Courtesy Public Domain Photos via Flickr

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!

EGUS Series Part 1: What’s the fuss over gastric ulcers?

Be it in the show ring or over dinner with horse friends, the topic of gastric ulcers always seems to elicit sentiments of frustration and misunderstanding.  What causes these pesky ulcers and what can we do as horseman to combat them?

To start, it’s important to understand that before horses were domesticated by humans, they spent their days slowly grazing across the plains and grasslands.  The slow ingestion of fibrous plant products creates an integral part of the horse’s digestive mechanism called a fiber mat, which naturally floats on the top of the stomach contents. 

Why is this fiber mat so important?  The horse’s stomach is separated into two regions, glandular and non-glandular.  The glandular region is responsible for the production of gastric acid which is necessary for the digestion of forage.  To avoid self-destruction, the glandular region of the horse’s stomach has protective mechanisms that keep the gastric acid from digesting the very tissue that produces it.  Unfortunately, the non-glandular region does not possess such protection and is susceptible to the destructive effects of the acidic stomach contents.  This is where the fiber mat comes into play.  Horses that graze throughout the course of the day are continuously adding plant fiber to the fiber mat which serves as a protective boundary between the acidic gastric contents and the non-glandular portion of the stomach. 

Let’s jump ahead to our typical domesticated horse which lives in a commercial boarding situation.  These horses are usually fed twice a day, often going more than twelve hours between their evening meal and breakfast.  The detriment here is without the continual ingestion of hay, that fiber mat is quickly digested and sent past the stomach into the rest of the GI tract.  This leaves the non-glandular portion of the stomach exposed and susceptible to the deleterious effects of the acidic stomach juices, as these secretions are produced on a continual basis.  Now, let’s say we decide to ride this horse without his fiber mat and the increased activity level causes more splashing of the stomach contents onto that already sensitive region.  As the acid begins to eat away at the lining of the non-glandular region of the stomach, the horse is thrown into a downward spiraling scenario that, without medical intervention, is quite difficult to recover from. 

How do you know if your horse has ulcers?  Common clinical signs of a horse with ulcers are aversion to tightening of the girth, sensitivity to grooming (especially behind the elbows), finicky eating habits or changes in behavior both on the ground or under saddle.  The only guaranteed diagnostic method to confirm the presence and severity of gastric ulcers is by passing an endoscope into the horse’s stomach and visualizing the integrity of the gastric mucosal lining.  For many of our clients, this is not a viable diagnostic mechanism, so instead, we assess the horse’s response to medical therapy for ulcers.  If there is a vast improvement in clinical signs over the course of therapy, the likelihood of gastric ulceration is high and we can continue with medical intervention and nutritional management. 

Stay tuned next month for part 2 of our blog discussing the treatment and management of horses with Equine Gastric Ulcer Syndrome (EGUS)!

Benefits of Gastroscopy

Most horse owners are familiar with equine gastric ulcers, or EGUS (equine gastric ulcer syndrome).  Gastric ulcers are extremely common in horses and likely underdiagnosed. Because horses evolved as grazing animals, their stomachs are designed for continual digestion and eating, continually secreting stomach acid. Management of the modern horse often prevents continual grazing, so periods of time without access to forage allow stomach acid to contact the stomach lining, causing ulcerated areas. Common risk factors include periods of time with an empty stomach (such as stalled horses without grazing access), stress (training, showing, travel), and administration of non-steroidal anti-inflammatories (phenylbutazone and banamine).

The gold standard for diagnosis is gastroscopy, where your veterinarian will examine the stomach and document findings with photos. Gastroscopy allows us to assign a score of severity to the horse’s ulcers as well as demonstrate healing following treatment. Recent technological advances have made this diagnostic modality available in the field, so gastroscopy can now be performed on the farm instead of trailering in to the clinic.

After you and your veterinarian have decided that gastroscopy is indicated for your horse, the most important part of the gastroscopic exam is patient preparation. Preparation requires fasting your horse for about 20 hours before the exam to ensure your horse’s stomach is empty. If there is food remaining in the stomach, your veterinarian will not be able to perform a complete examination. Frequently we recommend applying a muzzle to your horse during fasting since some horses will ingest shavings or straw. Water must be removed 3 hours prior to gastroscopy.

At the appointment, your veterinarian will sedate your horse to allow passage of the scope. The scope is passed up one nostril and to the back of the throat, when your horse will swallow it. During this process, the back of the throat can also be examined. After swallowing, the scope is passed down the esophagus (also examined) and then into the stomach. The upper portion of the stomach is called the squamous/non-glandular portion, based on the cell type composing the lining. The lower portion of the stomach is the glandular portion, where stomach acid is secreted. These 2 areas are divided by a  demarcation called the margo plicatus. Ulcers are most commonly found on the squamous portion of the stomach along the margo plicatus. The entire stomach is examined, including all the way to the exit of the stomach (pylorus) and ideally including the beginning portion of the small intestine (duodenum). A score is assigned to your horse based on location of ulcers and the severity of ulceration, ranging from 1-4. Your veterinarian will then work with you to determine the most appropriate treatment for your horse based on this exam. Ideally, the horse is re-scoped following treatment to ensure adequate healing and response to treatment.

MVS is excited to offer gastroscopy to enable appropriate diagnosis and treatment of EGUS, keeping your horse feeling and performing at his best. Contact us today if you’re interested in gastroscopy or would like to learn more.