Ulcers in Foals

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Also Known As

Foal gastric ulcer disease, Equine gastric ulcer syndrome, Gastric ulcers, Duodenal ulcers


Ulcers are essentially festering eroded sores in the stomach of the foal and can vary in size, sometimes affecting large areas of the stomach and the duodenum. The sores are usually covered with pus.

Mild gastric ulcers are seen in approximately 50% of foals during the first four months of life. Most ulcers in foals are considered to be related to the stresses of weaning. These ulcers occur in the stomach or just beyond the outlet of the stomach in the duodenum, which is the first few feet of intestine. The majority of ulcers do not produce symptoms and usually disappear as the foal ages.

Complications related to gastric ulcer can be severe in foals. They include perforation of the stomach lining, delayed gastric emptying, gastroesophageal reflux, esophagitis and megaesophagus (secondary to gastroesophageal reflux).

Ulcers in the duodenum can develop scarring, which leads to fibrosis and stricture and sometimes contracture of the stomach. In these cases, the nutrition of the foal is at risk. The foal may be reluctant to eat and may regurgitate feed and milk. Aspiration pneumonia may result when feed or milk are regurgitated and inhaled into the respiratory system.

Ulcers can perforate the stomach or the duodenum, spilling intestinal contents into the abdomen and causing fatal peritonitis.


Although many foals do not have any symptoms of ulcers, they do develop in a minority of foals and include:

  • Intermittent colic, often after nursing or eating
  • Poor appetite and nursing for only very short periods of time
  • Teeth grinding
  • Excessive frothy salivation
  • Diarrhea
  • Weight loss
  • Lying on the back
  • Poor growth
  • Potbellied appearance
  • Rough hair coat


Many ulcers in foals appear to be induced by the stress of transitioning from nursing to eating hay and grain. Most foals with an ulcer will readily consume hay and grass because the saliva secreted during chewing provides the bicarbs to make the stomach feel better.

The foal's stomach secretes hydrochloric acid continuously and the gastric acidity of a foal is very high during the periods between eating or nursing. Large doses of NSAIDs are known to induce ulceration and the effects of different grains or feed concentrates may play a role in the development of ulcers in the foal.

Ulcers also develop in foals during the neonatal period, in association with septic diarrhea and other infections. They may also occur at around 2 months of age when maternally acquired immunity begins to wane and again at 4 to 5 months, in association with weaning.

When a gastric ulcer is suspected, a veterinarian will use a combination of medical history, clinical signs, laboratory tests and examinations to make a diagnosis. Neither clinical signs nor laboratory tests are specific for gastric ulcers and another disorder could be causing the symptoms.

The only reliable method of diagnosis is having a veterinarian do an endoscopy to view the interior of the foal's stomach.

When duodenal ulceration in foals occurs, it may be either a peptic (acid-induced) condition or it may be an enteritis syndrome. Duodenitis appears to be an enteritis syndrome and duodenal ulceration, perforation and stricture can occur, but it is not known whether these problems develop solely as a result of enteritis or whether peptic factors have a role.


The most important prevention is to remove as many causes of stress as possible and treat any precipitating illness effectively and quickly. Good foal management is the key to preventing ulcers. Turning the foal out into the pasture to graze as frequently as possible often works wonders.

Creep feeding, where the foal has access to supplemental feed, has proven to be an effective means of ensuring that the foal gets the appropriate amount of nutrients to help the transition from foal to weanling. With creep feeding, the foal is able to satisfy its appetite on a frequent basis without having to jockey for a position to get the amount of food it requires.

A gradual weaning system is recommended to decrease stress at weaning time. During this process, foals need free exercise to promote healthy skeletal development. Since young, growing horses have the highest protein requirement to meet their lysine (limiting amino acid) requirement, a balanced diet, including high-quality forage, is important.

The recommended diet for a weanling contains 14 - 16% crude protein. Protein, minerals, and vitamins need to be balanced to meet the increased energy needed for training the weanling. Weanlings should be kept at a healthy body weight.

Limiting any feeding of grain or concentrates is important because they can set the stage for ulcers, since grain and concentrates lead to an increase in the production of gastrin, the hormone that stimulates acid secretion.

Some veterinarians recommend supplementing the foal's feed with bicarbonates in the form of baking soda, which most foals will consume readily, as it may help prevent formation of ulcers. Do this only when approved by your veterinarian.


The most important step in treating ulcers in foals is to remove all causes of stress and treat any precipitating illnesses effectively. Employing anti-ulcer drugs like omeprazole has been shown to be the most effective treatment in many cases. If the case is mild, over-the-counter antacids and histamine type-2 receptor antagonists, such as cimetidine and ranitidine, may be prescribed by a veterinarian.

If ulcers are diagnosed and medication is prescribed and given as directed, the foal will show improvement in a very short time, usually two to three days.

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