Ulcers in Horses 101: Causes, Symptoms and Recovery


An ulcer is another name for a sore. It can occur anywhere in the horse’s body. However, when veterinarians and horse owners speak of ulcers in horses, they are referring to gastric ulcers in horses or Equine Gastric Ulcer Syndrome (EGUS). These are sores in the stomach.

All horses of any age, including neonatal foals, can develop gastric ulcers. But it is seen mostly in extremely active animals, such as racehorses or Olympic competitors. If left untreated, ulcers cause considerable pain, weight loss, dull coat, diarrhea and frequent colic. A horse with gastric ulcers cannot compete at his best.

What Are Ulcers in Horses?

A horse’s stomach is divided into two layers – the top layer is the squamous or non-glandular lining. The bottom layer is the glandular lining. Gastric ulcers usually occur on the top lining as it is less protected from gastric acid than the bottom lining.

The average horse makes nine gallons of gastric acid every day. It all sits in the four gallon-sized stomach. Gastric acid is important for breaking down tough food like grass or hay. But it can also cause ulcers if the horse spends long portions of his day with an empty stomach.

What Causes Ulcers in Horses?

Horses evolved to eat a little bit for many hours in a day so that their small stomachs always have some food inside. In order to digest this constant flow of grass and other plant matter, the stomach is always ready for digestion by always producing acid – even at times when the horse is not eating. This is in contrast to human stomachs that only secrete gastric acid just before they eat.

When horses graze all day on a natural diet they always have a little saliva and food in their stomachs. This helps neutralize the strength of the gastric acid. However, modern horses do not eat hours a day and often need grain to have enough energy to race, breed or compete at shows. An empty horse stomach is a horse stomach that cannot protect itself against the full power of gastric acid. A stomach full of gastric acid and no food or saliva wears holes or sores into the stomach lining.

Horses that are in stressful conditions are also prone to developing ulcers:

  • Moving to another barn;
  • Being hauled over long distances in trucks or planes;
  • Competing in races or other high-stress events.

Treatment Options Available for Ulcers in Horses

There are three main goals of treating ulcers in horses:

  • Reduce the amount of gastric acid made by the horse’s body;
  • Make sure there is a buffer or material to help weaken the strength of the gastric acid;
  • Protect the horse’s stomach lining from further damage.

Treatment includes medications and supplements like probiotics. The most common medications for ulcers in horses include:

  • Histamine or H2 blockers: Histamine is the chemical which tells a horse’s body that it needs to make more gastric acid. H2 blockers help turn off this chemical. Common H2 blockers for horses are cimetidine and rantidine.
  • Protein pump inhibitors: This is another class of medications that work like H2 blockers. They need to be administered less often than an H2 blocker. The most frequently used protein pump inhibitor in horses is omeprazole.
  • Antacids: Work just like human antacids. However, antacids alone cannot help horses. They need to be given along with a protein pump inhibitor or an H2 blocker. They only work for an hour or less. This may help for a certain situation, such as the helping the horse compete at a show. But will not be a long-term solution.
  • Protectorants: These medications such as Sucralfate help protect the stomach lining. However, they are not considered effective over the entire area of the stomach.

Additional Options and Effects

If a horse is to have his or her grain reduced, nutritional supplements need to be added to water or hay to help keep the horse healthy. The supplements alone will not help combat ulcers. The change of diet, medications and other preventative measures will.

Adult horses should show signs of improvement within 48 hours of beginning medication. Young foals may not need medication. Sometimes their ulcers can heal spontaneously. Unfortunately, spontaneous healing does not happen in adults.

Prevention of Ulcers in Horses

Ut is known that horses in stressful situations are more prone to developing ulcers. So many vets including those at the University of California, Davis, recommend giving extra doses of omeprazole to horses about to compete or about to travel. It is currently thought that these extra doses should help prevent ulcers.

The best way to prevent ulcers in horses is through changes in feeding and management. Horses should get as much pasture time as possible so they can graze. Horses on grain need to have the grain split up into three or more small feeds a day. Horses that need to be stalled for most of the day need constant access to hay and should be able to interact with other horses and animals. Being alone is guaranteed to stress a horse out.

Painkillers such as NSAIDs should be used as little as possible. These medications have been shown to make a horse prone to getting ulcers. Talk to a veterinarian before making a drastic change in the horse’s diet or medication regimen.

Final Thoughts

Domestication has given the horse many advantages over living in wild herds. But one of its costs to the horse has been the high incidence of gastric ulcers. The bad news is that ulcers in horses represent a medical condition caused by people’s demands on the horse. In order to do the work people ask horses to do, horses need grain — a diet that the horse has not evolved to handle. They need to spend less time grazing and more time being active.

The good news is that caring horse owners can have high performance horses and can help treat and prevent ulcers. This is possible with changes in feeding, adding supplements and reducing the use of strong painkillers.

The images are from pixabay.com.

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