In a number of species, the ingestion of food and distension of the stomach are factors that stimulate the release of gastric secretions. Horses secrete hydrochloric acid continuously in their stomach, which therefore has a very low pH.

To date, three major causes and risk factors for the appearance of gastric ulcers have been clearly identified:

  • Feed: when changed too often, divided up, concentrated or lacking fibre
  • Training: during intense work
  • Changes in the environment: confinement in the box, transportation, unfamiliar places etc.

Other factors that can cause ulcers include musculoskeletal pain, general anaesthesia and treatment with certain anti-inflammatory drugs.

There are currently a number of confirmed and suspected risk factors in the genesis of gastric ulcers in horses:


  • Intense, repetitive and fast training or exercise
  • Long journeys 
  • Weaning or separation
  • Confinement in stable boxes
  • Changes to food 
  • General anaesthesia


  • Type of feed (especially feed with a high fermentable carbohydrate content)
  • Pain
  • Intercurrent diseases
  • Gestation
  • Certain medical treatments
  • Certain infectious diseases
  • Hereditary factors
  • Bacterial infections of the gastric mucosa

In a number of species, the ingestion of food and distension of the stomach are factors that stimulate the release of gastric secretions. Horses secrete hydrochloric acid continuously in their stomach, which therefore has a very low pH.

In their natural environment, horses spend 16 to 18 hours grazing per day and produce saliva rich in bicarbonates when chewing, thus neutralising the acidity of the stomach (buffer action). There is usually a balance between aggressive factors (acid, pepsin and other enzymes) and factors protecting the gastric mucosa (bicarbonates, mucus, food),thus promoting a stable pH and healthy mucosa. Gastric ulcers result from an imbalance between these aggressive and protective factors.

The consequences of ulcers are variable but can be dramatic in certain cases, ranging from colic and anaemia caused by bleeding, to peritonitis and even perforation.

What to do ?

a. Standard tests
Only a gastroscopy can confirm stomach ulcers and their severity, extent and location. All of these factors have an influence on the prognosis and treatment duration. The examination is carried out on the standing horse after it has been tranquillised and on an empty stomach for at least 12 hours.
A gastroscope (a three-metre flexible endoscope) is inserted through the nostril into the oesophagus and down to the stomach. The entire stomach is examined and the lesions are identified, located, measured and graded (on a scale of 0 to 4). They may be filmed and recorded so they can be monitored over time at future check-ups. Further gastroscopies are carried out after 15 to 30 days to monitor the lesions and the effectiveness of the treatment.

b. Therapeutic diagnosis
Where ulcers are suspected, even when a gastroscopy has not been carried out, the vet can prescribe the appropriate treatment on the basis of the physical examination (presence of symptoms such as teeth grinding) and confirmed risk factors (transportation, stress, training).
After three of four days of treatment, he or she may also establish a therapeutic diagnosis on the basis of clinical effectiveness

c. Possible further tests

A blood test may be useful to establish a minimum test profile (haematology and biochemistry) and enzyme assay (pepsinogen, gastrin, amylase, lipase, etc.), however the results cannot diagnose gastric ulcers with any certainty.

Finally, the sucrose test can also be used for non-invasive screening of horses suffering from gastric ulcers. Sucrose permeability tests are a good indicator of the presence of gastric ulcers in horses: where there are no ulcers, sucrose is not absorbed by the gastric mucosa. However, these tests are not specific and are less easy to carry out in practice than the gastroscopy, which is now widely used by vets.


a. Main treatment guidelines
The aim of any ulcer treatment in horses is to relieve pain, improve clinical symptoms, encourage healing, prevent complications and avoid relapse, while maintaining the balance of the gastric flora.
There are two main treatments to date:
Substances that provide gastric protection
Substances that regulate gastric acidity

b. Nutritional solutions
Nutritional supplements may also be recommended by your vet. In particular, Laboratoires Audevard has developed EKYGARD, a supplement specially designed for gastric mucosa comfort.
Ask your vet for advice.

c. Hygiene and prevention measures
It is essential to choose the right feed strategy to prevent gastric ulcers in horses. Food with high fibre content (hay ad libitum, free access to pasture), a diet split into multiple meals and reduced fermentable carbohydrate content (few cereals) are recommended.

Adding alfalfa hay or oil rich in fatty acids also appears to help reduce the appearance of ulcers.

Common sense is needed to manage the various types of stress. Arrange for rest periods during transportation, ensure sufficient and continuous hydration, and provide regular outings to the paddock for stabled horses.

Practical prevention tips :

Reduce stress:
Give supplements that protect the gastric mucosa when changing environment, work, feed etc.
Divide meals up as much as possible (four times per day)
Give hay ad libitum
Allow free access to the paddock or, even better, provide 24 hour turnout
Worm your horse regularly (depending on the results of the coproscopy) and treat it in autumn against bot flies.

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