Equine Ulcers and EGUS

Written by Mark DePaolo, DVM.  COPYRIGHT © 2012 All rights reserved.

What are equine ulcers?

Equine ulcers represent the single most preventable health issue horses face today. A product of modern horse keeping practices and stresses, gastric ulcers, small and large intestinal ulcers, cecal and colonic ulcers and hindgut acidosis can have a drastic impact on horse health, disposition and performance. Extensive research over the last two decades highlights the severity and scope of Equine Gastric Ulcer Syndrome (EGUS) – a collective term for ulcers and digestive upsets.

Indeed, a study published in the March 2005 issue of the Journal of Equine Veterinary Science notes that as many as 90% of performance horses have some kind of ulcer. The sheer numbers underscore the importance of promoting digestive tract health and understanding the causes, symptoms and treatments for ulcers and related gastrointestinal issues.

Equine ulcers fall into two primary categories – gastric (stomach) ulcers and hindgut ulcers. By far the most common and easily diagnosed type of ulcer, gastric ulcers are caused by excessive amounts of stomach acid. Elevated acid levels compromise the stomach’s lining and eventually lead to the formation of painful lesions and sores. These sores are repeatedly irritated by stomach acid and can produce significant health issues, ranging from grouchiness to colic and, in severe cases, death.

What is the difference between gastric ulcers and hindgut ulceration?

Gastric ulcers occur in the upper 10% of a horse’s gastrointestinal tract, and are thus easier to identify and understand. Modern diagnostic approaches, including the use of endoscopes, offer the opportunity to discover and treat gastric ulcers fairly efficiently.

Hindgut ulceration is equally troubling and perhaps a greater concern due to the difficulty in imaging and evaluating a horse’s lower gastrointestinal tract. A three-meter endoscope can easily identify stomach ulcers, but lacks the length to evaluate a horse’s hindgut. Making matters more difficult, equine colonoscopies are highly invasive and carry a significant mortality risk. As such, less is known about small intestinal, cecal and colonic ulcers, though studies indicate they are quite common and can have a considerable impact on overall horse health.

Hindgut ulcers occur when lesions form anywhere in the digestive tract behind the stomach. These sores are typically the result of a disruption in the  pH balance, a condition known as hindgut acidosis. The majority of equine digestive processes take place in the hindgut, where microorganisms ferment food and create volatile fatty acids – compounds that provide most of a horse’s energy.

When excessive amounts of undigested food pass from the stomach into the small intestines, lactic acid is produced and pH levels decline. This drop in pH can impede the production of protective mucous and affect the balance of microbes that aid in digestion, leaving the colon and hindgut vulnerable. A shift in hindgut pH can kill off helpful microbes and release endotoxins that can trigger colic and allow harmful microbes to take their place and possibly cause damage to the intestinal lining. Hindgut ulceration has also been linked to the use of non-steroidal anti-inflammatory drugs (NSAIDs), like Bute and Banamine.

These drugs can affect mucous production and blood flow, leading to ulcers.  Gastric and hindgut ulcers share many symptoms and external indicators. These common symptoms include weight loss and loss of appetite, negative changes in attitude and performance, irritability, cribbing, pawing or lying down excessively. Horses with ulcers may also express a reluctance to extend, collect or flex properly as well as exhibit a tendency towards colic and anemia due to inefficient digestion and nutrient absorption.

How did my horse develop ulcers?

Today’s horse lives a vastly different lifestyle than that of its ancestors. Thousands of years of evolution conditioned the horse to thrive as a free-grazing herd animal, ranging great distances and foraging on a variety of grasses and roughage. In contrast, the modern performance horse finds itself largely confined to stalls and sustained by measured meals high in grains and carbohydrates.

As caretakers, we have changed the way horses live, but we cannot change thousands of years of digestive evolution. Horses evolved to eat small portions, constantly. Thus, gastric acid production in horses is continuous and the stomach lining is left susceptible without sufficient food in the digestive tract.

By feeding measured meals two to three times a day, we increase the risk of gastrointestinal damage because there is not enough food to absorb and neutralize continuously produced digestive acids. Horses that are fed infrequently have empty stomachs much of the time and acids are left to slosh around unimpeded, eating into stomach lining and leading to painful gastric ulceration.
Although stomach acid is produced 24 hours a day, the best buffer of acid, saliva, is only secreted when the horse is chewing.

The issue of non-continuous feeding is exacerbated by the type of food typically given to performance horses – grains high in carbohydrates. Feeds high in carbohydrates, fed infrequently, increase the production of gastric acid and reduce production of saliva. As a result, today’s horses are at higher risk for gastric ulceration.

In addition, horses do not efficiently process large amounts of carbohydrates, thus much of the food consumed by modern horses passes through the stomach and large intestine before acids and digestive juices can adequately process it. Once carbohydrates reach the cecum and large intestine, they are bound to produce lactic acid and gas, lower pH levels and negatively impact the balance of helpful gut microbes. The result is an increased risk for hindgut acidosis, colic, and ulceration.

Are there other contributors besides feed?

While nutrition and feeding protocols are the largest source of gastric issues and ulcers, external and emotional stresses are also significant causes of gastrointestinal dysfunction. Extreme exercise and stresses like long-distance hauling can cause an increase in acid production. Combined with shifts and delays in feeding schedules, strenuous training sessions and transportation can make performance horses particularly vulnerable to acid build up, stomach lining damage and, ultimately, ulcers. This risk is amplified by the use of NSAIDs, which reduce blood flow to the gastrointestinal tract and disrupt acid-neutralizing mucous production. Finally, emotional stress can lead to an increase in acid production.

For many horses this emotional stress stems from the confinement lifestyle of stall living. As herd animals, horses are hardwired to be amongst peers in open spaces. Some horses do not cope well in stalls without the ability to survey their surroundings and regularly interact with other horses. This emotional distress can translate to an increase in acid production, raising the risk of damage to the stomach lining and the formation of gastric ulcers.

How are ulcers diagnosed and treated?

All types of ulcers are diagnosed primarily through the observation of symptoms. Horses exhibiting gas, bloating, diarrhea or attitude changes should be watched and further evaluated for ulcers. In addition, caretakers should watch for the following indicators:

  • Girth sensitivity
  • Aggressive attitude changes
  • Excessive tail ringing
  • Decreased performance or resistance to training
  • Teeth grinding or cribbing
  • Excessive lying down
  • Poor appetite or weight loss
  • Chronic colic

The presence of any of these indicators may suggest the onset of gastric or hindgut ulcers and the need for further diagnostic investigation. However, ulcers may be present without any significant outward indicators. One non-traditional diagnostic approach skirts the reliance on obvious outward indicators by palpating acupressure points closely associated with the digestive tract. A professionally trained equine chiropractor or acupuncturist can note the presence or absence of pain or sensitivity, suggesting the presence of unseen ulcers.

Traditional veterinary approaches often turn to an endoscopy to evaluate the upper gastrointestinal tract. This relatively costly approach involves the use of a small camera at the end of a three-meter long tube, or endoscope, to take images as it is passed through the esophagus to the stomach. The exam requires fasting and sedation, but offers a very effective means to positively identify or rule out the presence of gastric ulcers. However, endoscopy offers no means to accurately diagnose hindgut ulcers, as the three-meter tube is simply too short to investigate the lengthy hindgut portion of a horse’s digestive tract.

Another, less invasive, approach involves the use of a therapeutic trial with an anti-ulcer drug – essentially treating a horse suspected of having ulcers with ulcer medication. Gastric ulceration can be effectively treated though the use of medications containing Omeprazole™.  These drugs help to reduce acid production and act as an antacid.  For sensitive horses, or those known to have gastric ulcer issues, veterinarians often advocate the use of an Omeprazole™ product a few days before hauling or a competition. The drug’s acid reducing and neutralizing traits enable cautious caregivers to minimize the risk of stress-induced ulcers associated with increased work regimens, stressful new environments and extensive hauling.

As effective as Omeprazole™ products are in the treatment of gastric ulcers, they provide no relief for hindgut ulcers or acidosis. Reducing stomach acid production has no impact on these hindgut issues tied to excessive lactic acid release and gas production related to microbial fermentation in the large intestine and colon.  The best treatment for hindgut ulceration is prevention. Short of prevention, hindgut ulcers and acidosis are best treated through digestive support supplements – feed additives that promote overall gut health. Most of these digestive support supplements contain natural ingredients designed to sooth, reduce inflammation and promote a healthy pH balance and foster the presence of beneficial gut microbes.

Dr. DePaolo's has an easy do-it-yourself method of palpating acupuncture points as a great indication of the presence of painful and debilitating ulcers.  This involves palpating acupuncture points near the horse’s girth area. These points are closely associated with the digestive tract, and start just behind the withers, run down along the horse’s barrel (behind the elbow) and cross the sternum. If the horse reacts with pain or sensitivity, it is very likely that your horse has an ulcer. You may also notice a defensive or reactive response when saddling or brushing this area. Severe acidosis and un-diagnosed ulcers cause often very sensitive withers or chronic sore backs. 



How can I prevent gastric ulceration?

While gastric ulcers can be effectively treated through a drug protocol, the best possible approach to equine ulcers and gastrointestinal health lies in prevention. Research has yet to address the effects of long-term gastric acid suppression associated with continued Omeprazole™ administration. As such, drug therapy is best used in small doses – not as a long-term solution unless there is no viable alternative. Indeed, gastric issues can often be preempted by a thoughtful feed regime, the use of digestive support supplements, and minimizing external and emotional stresses whenever possible.

Contentious caregivers should carefully examine their feed selection and care regimen. Emulating a horse’s natural environment as closely as possible represents the best way to minimize the threat of ulcers and gastrointestinal issues. Whenever possible, horses should be afforded the choice of pasture, hay or both. The ability to graze continually will fill the stomach consistently, instead of incrementally, and neutralize the negative impact of constantly produced gastric acids on an empty stomach.

Caregivers should also consider a reduction in the amount of grain given during each feeding. While concentrate types of feed are sometimes essential to provide the energy required for performance horses, the negative effects of high-carbohydrate diets on the digestive system are counterproductive.

As an alternative, caregivers should consider substituting moderate protein source and fats for all of the grains/carbohydrates. Suitable high fat/high fiber substitutes include rice bran, and alfalfa pellets will act as a moderate protein source. Any grain should be carefully reviewed to ensure it has a low glycemic index, as high-sugar feeds can result in a rapid decrease in the hindgut pH and a higher risk of acidosis and ulceration.

Finally, caregivers should try to feed small meals often. This practice ensures there is always food in the stomach to prevent unchecked stomach acid from irritating the stomach lining. Providing several small meals a day also reduces the risk associated with large quantities of undigested, carbohydrate laden food being passed into the intestines. By minimizing the amount of food processed at one time, the threat of hindgut acidosis and ulcers is cut significantly. All feed changes should be conducted gradually, as studies have indicated that nearly one-third of colic cases can be linked to recent dietary change. As such, changes to a feed protocol should be implemented over the course of one to two weeks.

Aside from a carefully planned feed protocol, a digestive support supplement, such as Excel, represent the best option for promoting digestive health and minimizing ulcer-related issues.  This daily supplement can help reduce inflammation and soothe a previously ulcerated digestive tract. By incorporating fiber, prebiotics and natural anti-inflamatory ingredients, Excel encourages healthy populations of micro flora to aid in nutrient absorption and normalize the digestive tract, thus reducing the threat of hindgut issues.

This information is for educational purposes only and should not be considered as Dr. DePaolo diagnosing your horse’s health. DePaolo Equine Concepts, Inc. recommends that you consult your regular veterinarian regarding specific health concerns.

At a Glance:

  • Equine ulcers represent the single most preventable health issue horses face today.
  • Performance horses are regularly subjected to  the use of non-steroidal anti-inflammatory drugs (NSAIDSs), extensive hauling and exhaustive training sessions which are all contributors to developing ulcers.
  • Research suggests that horses allowed to move at will have a lower incidence of colic and ulcers than those that remain stall bound.  In general, the healthiest horses are invariably those that are allowed to live as natural a life as possible.
  • Equine ulcer diagnosis can easily be done without the need for a vet.
  • A carefully planned feed protocol and a digestive supplement, such as Excel, represent the best option for promoting digestive health and minimizing ulcer-related issues.