In the last few years the recognition of equine gastric ulcer syndrome (EGUS) has become more commonly identified amongst the horse population with the greater accessibility of video gastroscopy.
It has been a difficult condition to identify by its clinical signs as they are not unique to EGUS and are often subtle. It is however a significant disorder affecting performance, appetite and temperament.
The incidence in racehorses has been found to be over 80% and in competition horses up to 70%. It is the most common disease of horses but still greatly under-diagnosed.
Following treatment most horses show a big improvement in performance (improved placing of horses/wins in races), better temperament (decreased bucking, more placid under saddle, less aggression), better appetite and improved condition.
Why does it happen?
The horse in its natural environment should spend up to 16 hours per day feeding in a herd, with the occasional need to move at high speed to evade predators. In this state the horse’s naturally acidic stomach contents are buffered by saliva produced in response to regular eating. With normal gentle relaxed movement, the gastric contents generally are restricted to the lower glandular part of the stomach rather than the upper part lined by stratified squamous epithelium. The glandular part of the stomach is protected by a mucous/bicarbonate protective layer, rapid cell turnover, prostaglandin and intracellular tight junctions. The upper stratified squamous epithelium lacks these defensive mechanisms but in the natural situation rarely comes into contact with the acidic stomach contents.
By domesticating the horse we have done the following, these factors lead to EGUS:
- Reduced the time that it spends eating – decreasing saliva production.
- Regularly exercised the horse – splashes contents around the lining and reduces blood flow to the wall.
- Reduced the amount of forage in the diet and restricted feed intake.
As mentioned above the clinical signs are variable and often subtle and may well be shared with a number of other conditions. The symptoms may include one or more of the following symptoms:
- Poor performance.
- Reduced appetite.
- Altered temperament – difficult to ride, bucking, refusing at jumps.
- Weight loss.
- Teeth grinding.
- Crib biting.
- Back pain.
- Peritonitis and death (extremely rare).
The only accurate method of diagnosis and monitoring of the condition is by gastroscopy. Patients should be starved for 12 hours before this procedure and their water supply should be removed four hours beforehand. During the examination the horse’s oesophagus, stomach and proximal duodenum are visualised and inspected. Ulceration is graded on a scale of one to four with one being mild thickening only to four being deep widespread ulcers. Bleeding does not relate to the depth or the severity of the ulcer. It is important to assess the stomach by gastroscopy, to confirm the presence of ulcers to avoid treating unnecessarily.
The licensed veterinary product is omeprazole, a proton pump inhibitor, which is marketed under a variety of trade names including Gastrogard and Peptizole. This is by far the most effective treatment for the vast majority of cases. Other drugs used include cimetidine and ranitidine, H2 receptor antagonists, and sucralfate, a mucosal binding agent It is estimated that around 80% of cases have complete resolution of gastric ulceration after four weeks of treatment, however because approximately 20% of cases need longer treatment courses, we strongly recommend repeat gastrocopy after four weeks of treatment to ensure complete resolution before stopping treatment. The combination of management changes, drug treatment and, in some cases, long term supplementation with products aiming to promote good gastrointestinal health, usually leads to successful resolution of the ulcers and their accompanying clinical signs.
If you would like to discuss gastric ulcer syndrome the please contact Mark or Yolanda at the surgery.