Stomach & Intestinal Disorders in Horses

Intestinal Disorders

Diarrhoea and colic are the most common intestinal disorders in horses. Colic is another term for abdominal pain and encompasses all abdominal disorders ranging from relatively harmless to life threatening; and can be caused by many different things. Colic can be divided into several categories, including sand impaction, gas (or tympanic) colic, spasmodic colic, obstruction, inguinal herniation or displacement of the bowel.

Clinical signs of colic include repeatedly lying down and rising, pawing, increased attention toward the abdomen (flank watching, nipping, biting or kicking), loss of appetite, decreased fecal output, sweating, rolling over, etc. Different treatment methods can be used depending on the underlying cause of colic and the severity of the clinical signs. In some cases conservative therapy, through means of painkillers, muscle relaxants or paraffin are sufficient. In extreme cases, surgery is the only method of treatment.

Sand Impaction

Sand impaction is most likely to occur in horses that ingest high amounts of dirt or sand while grazing. The sand or dirt that is ingested sinks to the bottom of the intestines and starts to accumulate. Signs of an active sand impaction include sand in the faecal matter. The build up of sand is visible on a medical ultrasound. Treatment of sand impaction includes paraffin or psyllium, which allows the sand to be moved out of the tract with manure. Vetsend has an extensive assortment of products that may stimulate the expulsion of sand preventatively or before the development of clinical signs.

Gas Colic

Gas colic, also known as tympanic colic, occurs as a result of the overproduction of gas in the horse's gastrointestinal system. The gas buildup can cause a rise in pressure inside the tract, which is painful for the horse. If left untreated, gas buildup could lead to displacement of the bowel. Exercise, such as walking around, should provide some relief for horse's suffering from this type of colic.


For the most part a horse's gastrointestinal tract is not attached to the body wall, which makes movement easy for parts of the intestine and could lead to part of the intestine to become trapped. A trapped bowel as a result of displacement causes a lot of abdominal pain. Bowel displacement of (part of) the small intestine is seen in inguinal and umbilical herniation. Conversely, the large intestine can also cause problems, such as, left dorsal displacement (nephrosplenic entrapments), where the left dorsal colon becomes trapped in the space between the spleen and left kidney; right dorsal displacement, where the right dorsal colon becomes trapped between the caecum and body wall; torsion, a twist along the longitudinal axis of the intestine; and volvulus, where the intestines twist along the axis of the mesentery.


There are two different types of gastrointestinal obstruction in horses: partial and complete obstruction. A complete obstruction causes severe abdominal pain and is most commonly caused by eating large quantities of bedding/mulch, like flax or hay, or a worm infestation. The latter usually occurs in foals and can cause problems shortly after a worming treatment.


It is possible for diarrhoea in horses to be completely innocent, particularly if it is stress-induced and covers a brief period of time, for example at a competition or during transportation. On the other hand, diarrhoea can have a severe underlying cause, such as a worm infestation (especially in foals), a poor or unstable diet, the presence of sand in the intestines or a disruption of the intestinal flora. The latter can be caused by a lack of nutrients in their diet or a long-term course of antibiotics. It can also give bacteria such as Salmonella or Clostridium the chance to flourish, damage the intestinal mucosa and lead to severe diarrhoea.

Stomach disorders

Equine Gastric Ulcers

Certain circumstances can cause a horse's gastric mucosa to become inflamed or swollen. It is presumed that approximately 50% of all horses suffer from gastric ulcers, to some extent. In thoroughbreds, this estimation increases to approximately 80%. The most common causes of gastric ulcers are nutritional errors, stress and medication. Clinical signs include a loss of appetite, dull coat, poor performance, yawning, bruxism and mild colic. A gastroscopy (endoscopic visualisation of the stomach) is the best method of diagnosis for gastric ulcers. It is important to treat the underlying cause as well as setting up a suitable treatment plan to tackle the gastric ulcers.

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