Equine gastric ulcer syndrome can be a cause of poor performance, behavioural problems, poor condition, recurrent colic and more. The term equine gastric ulcer syndrome is an umbrella term for two conditions – squamous disease and glandular disease.
The equine stomach can be divided into two parts:
- The bottom two thirds of the stomach is known as the glandular portion, lined by glandular mucosa. This mucosa produces acid and digestive enzymes for digestion and mucous for protection, it is therefore well adapted for contact with acid.
- The top third of the stomach is known as the squamous portion, lined by squamous mucosa. This mucosa is sensitive and not well adapted for direct contact with acid.
Equine squamous gastric disease (ESGD) is well understood. Due to the nature of this mucosa and its limited defence mechanisms, ulceration in this area is caused by direct acid injury.
Risks for squamous ulceration include exercise, fasting and increased acidity in the stomach contents.
- Exercise – exercise increases the pressure in the abdomen which causes acid to be pushed up and splash onto the squamous mucosa. The higher the intensity of the exercise the greater the splash effect is.
- Low forage diet – horses have evolved to eat a high fibre trickle diet, therefore they need constant access to forage. Chewing forage produces saliva – this saliva contains bicarbonate which buffers the acid produced by the stomach
- High concentrate diet – hard feeds don't produce the same quantity of saliva as forages do. They also result in greater production of volatile fatty acids contributing to an increase in acidity of the stomach contents
- Prolonged periods without food – longer than 6 hours between forage feeds greatly increases the risk of ulcers
The risk factors for equine glandular gastric disease (EGGD) are not as well understood as squamous disease. The exact reasoning as to why we can see a failure in the stomach's natural defence mechanisms is unknown, however it is often highly influenced by external risk factors:
- Exercise – there may be a link between exercise and reduced gastric blood supply, frequency of exercise appears more significant than intensity for glandular disease. Performing exercise more than 4-5 days per week has been shown to increase the risk of EGGD in racehorses.
- Stress – causes of stress such as reduced turnout time, box rest, isolation or just general changes in routine. Studies show stressed horses are more likely to develop gastric ulcers however again the link is not well understood.
- Concurrent pain – there may be some association between orthopaedic disease and EGGD, however this requires further investigation
So with these risk factors in mind, what can you do to help reduce the risk of gastric ulceration?
Squamous ulcers
- Feed 2 litres of chaff or an equivalent volume of forage 30 minutes prior to exercise – this creates a fibre matt on the surface of the stomach acid and reduces splash
- Ensure constant access to good quality forage
Glandular ulcers
- Provide 2 rest days from work per week
- Maximise turnout time
- Minimise management changes and stress factors
- Address any concurrent conditions that may be causing pain