Its well known that gastric ulcers affect many racehorses, it is less well known that around 60% of performance horses and approx 40% of leisure riding horses are also affected by this condition. The non-specific nature of the equine gastric ulcer syndrome (EGUS) means that it is possibly a very much under reconised problem, however progress in the developement of diagnostic equipment has helped veterinary surgeons identify and confirm the presence of ulcers in horses, a long endoscope (gastroscope), 2 to 3 metres long passed down ainto the horses stomach is the only definitive test to verifiy the presence of gastric ulcers.

Symptoms

One of the challenges of this condition is the variablility and vagueness of the symptoms, which can include some of the following; reduced appetite, slow eating, poor physical condition, dullness, changes in attittude such as sourness or irritability, colic, poor performance and reluctance to work. However at times it is difficult to attribute these signs specifically to gastric ulceration.

To add to the complication, the correlation between clinical signs and severity of ulceration is not always consistant. On examination, some horses have shown relativly few clinical signs are found to have severe ulceration, whereas the reverse has been found in others.

How and why are ulcers thought to form

Horses are designed as trickle feeders with free access to grazing, in contrast depending on the level of work and yard regime our modern horse in traing is usually stabled, often with restricted access to food, an important feature of equine gasteric ulcers is that horses secrete gastric acid continuosly, whether or not he is eating, an adult horse will produce approximately 1.5 litres of gastric acid per hour and with restricted access to food continued secretion means the pH level can rapidly become very acidic and ulcers can start to develop, however horses that are constantly eating hay or grass have ahigher average stomach pHlevel providing a heathier enviroment.

The horses stomach is effectivly divided into two portions the upper and lower region. The lower part of the stomach has gastric pits containing the glands that secrete hydrochloic acid. Its lining is less susceptible to acid attack than the upper part, which is lined with squamous mucosa which has no secetory or absorptive function and is therefore vunerable to acid attack. Gastric ulcers usually form when the lining of the upper part of the stomach is exposed to acid for extended periods of time.

Exercise and travel

Research has shown that training has an effect on stomach acid levels. Horses fed the same diet prior to and during training had higher acid levels during the training period. More recent studies have also discovered what is known as the mechanical effect. During galloping pressure from the abdomen causes the stomach to contract pushing acid from the lower stomach up into the more vunerable upper stomach, thus further increasing  acid exposure in these animals.

In addition to the feeding regime and exercise other factors that can influence the formation of ulcers are transportation, the frequent competions and unfamilier suroundings, the use of non-steroidal anti-inflammatories such as bute has been shown to contibute to equine ulcers.

Diagnosis and treatment

If a horse is suspected of having ulcers gastroscopy will confirm the presence, severity and location of the ulceration.  Although the most common location is in the upper region of the stomach ulcers do develop in other areas including the lower portion of the doudenum. Ulcers are graded from 0 to 4 reflecting on the severity of the ulceration with grade 0being a normal heathy stomach and grade 4 demonstrating extensive leisions with areas of apparent deep ulceration.

Studies have shown the most effective treatment is the acid inhibitor, omeprazole. This is sold under licence as GastrogardR , this is the only licensed treatment for equine ulcers in the U.K. An orasl paste it isa potent inhibitor of grastric acid secrtion and is highly effective in healing gastric ulcers, it takes 3 to 5 days for a steady state of acid suppression to be reached and total healing time is usually between 2 to 4 weeks, although severe cases can take a little longer

A full course of tratment is prescribed for 28days with one treatment a day the horse can be taken out of work during this period but it is not always necessary and really depends on the individual circumstances and preference of the owner/rider, if you think your horse might have ulcers we reccomend you consult a veterinary surgeon

Re-occurence and prevention

Many owners and riders note a sinificant improvement in their horse, sometimes within days of treatmen.t However once the ulcers have healed unless you make changes to your horses regime the ulcers are likely to return. For a horse in hard work ulcers can start to appear as early as 3or 4 days after the end of treatment however even subtle changes to the daily regime can make a difference.  Because horses are trickle feeders we must try to emulate the horese natural environment as closly as possible, free access to hay daily turnout- even for short periods- can help significantly. Access to grazing plays an important part in the prevention of ulcers in horses. We knowthat where horses have been rested at grass for a few weeks the incedent of ulcers will be minimal but once brought back into work and stabled full time the a good proportion of animals will develop ulcers within 3 to4 weeks

Administration of hard feed in smaller quantities more frequently I.E the same amount in total given 4 times day instead of 2 can help.

In additition to management modifications, or where the regime alredy emulated a more natural environment, horsrs of high risk of recurrence may also require an ongoing preventive dose of gastrogard to keep them clear of ulceration. In our continuation to create greater awareness of equine gastric ulcers, the clyde veterinary group  is holding a gastroscopy clinic and seminar later this spring. Gastrogard is a registered trademark of the astraZenica group of companies. Legal category POM-V GastroGard contains Omeprazole