Equine Gastric Ulcer Syndrome (EGUS)
In recent years the veterinary profession has identified equine gastric ulcers (EGUS) as a major health problem for many horses. EGUS can be responsible for a wide range of clinical signs including:
Behavioural changes including aggression
Mild / recurrent colic
Stretching to urinate
Discomfort on girth tightening
Linked to crib biting
Spending lots of time lying down (excessive recumbency)
Horses can have potentially serious gastric ulcers with no clinical signs at all!
Which horses are at risk?
EGUS can affect any horse at any age. Studies indicate that it is a very common problem with percentages of occurrence ranging in different groups of horses: about 35% of non – performance horses, 60% of performance horses and 90% of racehorses have been found to be affected. Foals are at a particularly high risk from EGUS and if young foals undergo treatment for any other disease, it is wise to start preventative treatment for ulcers as well.
Diagram illustrating the anatomy of the equine stomach. Most ulcers occur just above the junction between the glandular part and the squamous part – this is called the margo plicatus.
Why do horses get gastric ulcers?
To answer this question you must first have some understanding of the basic anatomy of the horse’s stomach. Basically the top part of the stomach is lined by ‘squamous epithelium’ and the bottom half by ‘glandular epithelium’. The squamous (upper) part is easily damaged by acid secretions – causing ulceration. The glandular (lower) part is able to produce a bicarbonate – rich protective mucus layer and is less likely to be involved in EGUS – although ulcers can and do occur in this part of the stomach. The lower part of the stomach produces hydrochloric acid which is vital for the digestion of food. Splashing of that acid onto the squamous part of the stomach can result in ulcers. Usually there is a fibrous mat of food material floating on top of the acidic stomach contents which helps protect against ulcers.
All the factors that contribute towards ulceration are not fully understood but some risk factors have been identified;
Training and exercise – when exercising the blood flow to the stomach decreases resulting in reduced acid removal, this coupled with increased pressure in the abdomen results in acid being pushed up onto the squamous lining of the stomach.
Diet – horses are normally trickle feeders taking little and often rather than eating large meals and living on roughage only. Prolonged periods without food can lead to increased acid contact with the lining of the stomach. When horses are starved ulcers can form relatively rapidly. Concentrate feeds with high carbohydrate levels make the stomach more acidic.
Physical stress and illness – this might include transportation or stable confinement. Horses that have had surgery or other treatment are probably at greater risk.
Medication – using most NSAIDs (e.g. ‘bute’) at normal doses is NOT associated with EGUS however used at very high doses and combined with steroids they may be a risk factor.
Bacteria – in people bacteria play an important role in gastric ulceration (Helicobacter Pylori) but in horses the significance is still unclear. In some cases in horses antibiotics are needed to heal persistent ulcers.
Can ulcers be treated?
The good news is that EGUS is a treatable condition. A product called Gastrogard which reduces the production of acid in the stomach is curative in up to 90% of cases. But you also need to look at management and feeding practices to ascertain what can be done to decrease the chances of recurrence of the problem.
There a number of dietary supplements that can assist in the management of cases or the prevention of recurrence.
Table showing the effectiveness of the well-known anti-ulcer drug Gastrogard compared to a placebo (sham treatment). It should be noted that up to 10% of cases require further treatment before improving.
The Gastric Ulcer Clinic.
Pool House Equine Clinic has a video gastroscope and holds regular gastric ulcer clinics.
Before scoping a horse MUST be completely starved for about 16 hours (no more than 6 hours in young foals). Water should be allowed up to 2 hours before scoping. Mild sedation is usually necessary.
Phone our practice for further information about the gastroscopy clinic.