Stomach Ulcers in Horses and Foals

By Dr Dave Mullins: Equine Veterinary Services


Stomach ulcers are a common finding in normal horses and foals, 51% of these are asymptomatic.  Clinical signs of ulcers are mostly seen in performance horses, especially race horses; and foals.


Ulcers are caused by an increase in acid production in the stomach.  This results in damage to the stomach lining.  There are several risk factors that contribute to this increased acid in the stomach.

1) Intermittent vs continuous feeding:

Horses that graze continuously are at lower risk that those where feed is withheld.  This is because there is a continuous flow of saliva which buffers the acidity in the stomach.  When feed is withheld the acidity increases.

2) Diet:

Horses fed a high concentrate diet are more at risk, due to the large amount of digestible carbohydrate which is fermented in the stomach.  This increases the acidity.

3) Transport:

During transport water and feed consumption is generally less.  When horses are transported long distances, there is a risk of dehydration, increased respiratory disease and immune suppression.

4) Stabling:

The causes for this are multifactorial.  Diet, feeding regimes and stress may all be implicated.

5) Anti-inflammatory drugs ( Phenylbutazone, Finadyne):

These drugs tend to cause a decrease blood flow to the stomach.  The risk is increased when the horse is dehydrated and in appetent.

6) Foals:

Age and recent illness are two important risk factors in foals.

Clinical signs:

Adults: Acute colic, Recurring colic, Poor body condition, Picky eating, Poor performance/training, Attitude changes, Excessive recumbency

Foals: Diarrhoea, Abdominal pain, Restlessness, Rolling, Lying on its back, Grinding teeth, Intermittent nursing, Poor appetite, Acute colic.  Beware that these signs may also indicate other intestinal diseases.


Gastroscopy (a scope of the stomach) is currently the only way to make a definitive diagnosis of ulcers.  This is not always readily available, as a specialised endoscope is required for the procedure.

If ulcers are strongly suspected due to clinical signs and history, and gastroscopy is not available or cost prohibitive, it may be worth starting on a trial course of ulcer treatment. Most often Gastric Ulcers are diagnosed by the response to treatment.

Treatment and Prevention:

The goal of treatment is to relieve pain, eliminate clinical signs, promote healing, prevent secondary complications, and prevent recurrence.  The main aim is to decrease stomach acidity.  Because the recurrence rate is high, treatment should be followed by changing management, and long-term use of anti-ulcer medication.

Acid suppression therapy: These drugs neutralise stomach acidity. Examples are

  • Ranitidine; this drug needs to be administered three times a day, and as such management routines may prohibit its use,
  • Omeprazole; this only needs to be given once daily but in most cases is prohibitively expensive.
  • A treatment that is currently very popular at the clinic is Equitop Pronutrin.  This is given in the feed, and can be used as a preventative treatment for horses that are prone to ulcers.

Duration of treatment: Each horse reacts differently to treatment, so it should be tailored for the individual horse.  It is recommended to keep the horse on treatment for at least 28 days. It is important to note that clinical signs may resolve before the ulcers have healed completely.  Spontaneous healing may occur in horses where the risk factors are low.  However this is generally not the case in horses that continue intensive training; and ulcers may recur if treatment is discontinued.  These horses generally need ongoing preventative treatment.

Dietary Management:

Dietary and environmental management may facilitate the healing process.  Providing constant access to good quality hay and, or Lucerne may help decrease the acidity in the stomach.  Pasture turnout is the best dietary method of controlling ulcers.

Prevention varies on an individual basis.  This is due to the level of performance of the horse.  Race horses, in intensive training, and show horses require more intensive management and ongoing treatment compared to broodmares, and pleasure horses, which spend a large amount of time in pastures.



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