Equine Gastric Ulcer Syndrome (EGUS)

By Nia O'Malley, BSc. Eq. Science

Every horse owner appreciates the delicate nature of the horse’s gut. Gastric ulceration is a widespread condition which unfortunately seems to affect mainly adult horses in high performance work.

Recent studies have indicated that over 93% of racehorses and 63% of competition horses are affected. However, only 50% of those presenting with gastric ulceration may actually show clinical signs.

Unlike gastric ulcers in humans, which is caused by a Helicobacter pylori bacterial infection, Equine Gastric Ulcer Syndrome (EGUS) appears to be a predominantly man-made problem, resulting from a variety of factors, including physical and psychological stressors, medications and underlying diseases. Diet and feeding management also play a part, as in limited access to forage, meal feeding, fasting and high carbohydrate diets.

There are many clinical signs and symptoms that are associated with EGUS. Common signs include poor performance, colic and poor appetite. Other signs include attitude changes, poor body condition, a tucked up appearance or a dull coat.

It is important to note that in many horses, the clinical signs of stomach ulcers may not be noticeable. In fact, by the time obvious symptoms appear, stomach ulcers may be advanced and more difficult to treat. The presence of ulcers can be confirmed through examining the inside of the stomach through an endoscope, but certain symptoms strongly suggest ulcers.

The major cause of gastric ulcers in horses is prolonged exposure of the squamous mucosal lining to gastric acid. Gastric mucosal damage can manifest as inflammation, with no break in the integrity of the surface; erosion, where just the superficial layer is affected; or an ulcer, where the lesion penetrates deep into the stomach wall, sometimes causing bleeding if a vessel is involved, or sometimes penetrating all the way through, causing serious or fatal peritonitis.

The horse’s stomach is divided into two parts. The bottom glandular part that secretes acid and has a protective mucous coating to keep it from being damaged by the acid, and the upper, non-glandular squamous portion of the stomach, which is designed for mixing of the contents of the stomach.

The only protection that this portion of the stomach has from gastric acid comes from saliva production. If adequate saliva is not produced to buffer the gastric acid and coat the surface of this part of the stomach, then gastric irritation occurs and ulcers may develop.

A horse’s natural diet of highly fibrous food ensures adequate saliva production. Restricting forage availability for horses in training may help reduce gut fill, but unfortunately it also helps reduce the horse’s own ability to buffer stomach acid.

Unlike humans, horses secrete gastric acid continuously, whether they are eating or not. This accommodates their natural lifestyle perfectly, since horses by nature are continuous grazers, eating small amounts of relatively fibrous forage throughout most of the day. As a result, the stomach is never empty and the lining is always protected from the gastric acid by the ingested food.

Modern training practices, however, incorporate meal feeding as opposed to trickle feeding, and as a result, the horse endures long periods of fasting in between meals, during which time gastric acid begins to accumulate.

Similarly, with high performance horses fasted before intense exercise, with the onset of work, the squamous mucosa can get entirely bathed in gastric acid. Also, horses not eating due to an underlying medical condition - or from stress - are in danger of developing ulcers. Prolonged periods of fasting can cause gastric inflammation or erosions in as little as 24-48 hours.

The high energy demands of competition require a high energy diet. Grain has always been the forerunner in providing energy in the horse’s diet, but unfortunately it has its disadvantages - it actually increases gastric acid secretion.

Grain causes an increase in the production of a hormone called gastrin, which is released by the stomach and acts as a stimulant for acid secretion. Feeding high grain meals with limited access to forage leads to excess gastric acid output without adequate saliva production to buffer the acid.

Alternative sources of energy can be added to the diet in place of grain such as fat (rice bran, soya oil) or superfibres (soya hulls, beet pulp, alfalfa).

The treatment of stomach ulcers involves a combination of changes to feeding management, medical therapy, as well as reducing stress. Turning a horse out to pasture for a month will heal most ulcers, but this is not always practical. For the ulcer to heal, gastric acid secretion will need to be inhibited or the acid that is secreted neutralised.

There are drugs available to inhibit gastric acid secretion, cimetidine (Tagamet), ranitine (Zantac) and omeprazole (Gastroguard), with the latter being the most effective, but also the most expensive. An alternative to restricting acid secretion is to neutralise the acid secreted with the use of antacids.

However, it is the prevention and management of ulcers that is the key. Removing predisposing factors such as obvious sources of stress and treating underlying disease, adjusting the horse’s daily routine to incorporate as much turnout as is practically possible, and most importantly, revising the horse’s diet.

When reviewing dietary changes, the best way to prevent gastric ulcers is to mimic the life of a horse at free range, i.e. providing a constant supply of fresh forage, trickle fed or free choice, so as to stimulate saliva production, nature’s best antacid, which will neutralise gastric acid, and to feed frequent but small low carbohydrate high fibre meals.

Horse Care Cubes has been specially formulated to complement a feed management programme that is as close to nature as possible. Being a beet pulp, alfalfa and oil based product, it is naturally high in fibre and oil, and with limited grain, it is relatively low in starch. It also contains natural antacids to help act as a buffer to gastric acid and complements a balanced and healthy regime for the management of ulcers.

An all round management approach is vital for a long-lasting solution for horses prone to gastric ulcers. Feeding, exercise and stress must all be carefully managed to prevent and treat this distressing and performance inhibiting condition.

Our experts recommend avoiding exposing your horse’s stomach to long periods without food. Be sure to provide adequate forage, allow as much access to grazing as possible and finally, feed concentrates in small regular meals, ideally 3 or 4 times per day. Common sense also points towards minimising stress and avoiding excessive exercise.

With over 100 years of experience and dedication, Connolly’s RED MILLS have come to understand what it takes to create the very best food. With the knowledge and expertise gained throughout the years, our equine nutritionists have created an advanced feed specifically formulated for horses suffering from gastric ulcers or tying up.

Taking our lead from nature, Connolly’s RED MILLS have developed Horse Care Cubes, with its innovative and wholesome approach to equine nutrition, which is reflected in their tag line - nutrition as nature intended!

For further information on EGUS, contact the RED MILLS nutrition team