Equine Sand Colic

Other Names

Sand colic; psyllium colic; sand impaction; sand accumulation colic.

What is Equine Sand Colic?

Equine sand colic is a form of large intestinal colic caused by the accumulation of sand and fine grit in the horse’s digestive tract, particularly in the ventral colon and caecum. Horses ingest sand and soil particles when grazing on sparse pastures, eating from the ground, or consuming hay and feed that has been placed directly on sandy or gravelly ground. Over time, these particles accumulate and can cause irritation, inflammation, impaction, and in severe cases, displacement or rupture of the bowel.

Sand colic is more prevalent in certain geographic regions — particularly sandy coastal areas, drought-affected paddocks with little ground cover, and dry summer conditions where horses are forced to graze close to the soil. It is one of the more preventable forms of colic, making management practices critically important for horses kept in these environments.

The condition can range from mild and self-limiting with appropriate treatment, to a life-threatening surgical emergency. Even horses that appear to have recovered can experience recurring episodes if the underlying management issue is not addressed.

Causes

The primary cause is simple: horses ingest sand and soil particles over an extended period. Contributing factors include:

Grazing on bare, sandy, or overgrazed paddocks
Feeding hay or hard feed directly on sandy ground
Drinking from shallow water sources that become silty
Living in environments with naturally high soil particle content
Pica behaviour — some horses actively eat soil due to mineral deficiencies or boredom

Sand is heavier than feed material and settles in the dependent portions of the large colon. As accumulation increases, it physically impedes the normal flow of ingesta, causing distension, pain, and reduced motility.

Symptoms and Signs

Signs of sand colic can be chronic and low-grade, or they can present acutely and severely depending on the amount accumulated and the degree of obstruction. Common signs include:

Recurrent mild colic — often dismissed initially as routine digestive upset
Pawing, looking at flanks, or rolling
Reduced or absent gut sounds, particularly in the lower right abdomen
Loose or intermittent diarrhoea (sand irritates the bowel lining)
Weight loss despite adequate feeding
Pot-bellied appearance in horses with large chronic sand loads
Severe acute abdominal pain in cases of impaction or displacement

A useful field test is the sand settling test: collect fresh faecal material in a rectal glove or plastic bag, add water, and observe whether sand settles at the bottom over 15 minutes. Sand present in faeces indicates ongoing ingestion, though its absence does not rule out accumulated sand in the colon.

Diagnosis

Your vet will perform a thorough clinical examination including rectal palpation, gut sound assessment, and nasogastric intubation if indicated. Abdominal radiography is the gold standard for confirming sand accumulation — X-rays clearly show the characteristic ground glass opacity of sand deposits in the ventral colon. Ultrasound examination can also provide supporting evidence, though it is less definitive for quantifying sand loads than radiography.

Bloodwork may reveal signs of dehydration, electrolyte imbalances, or early signs of endotoxaemia in more severe cases. Peritoneal fluid analysis may be indicated if the vet suspects bowel compromise.

Treatment

Mild to moderate cases are managed medically. Psyllium husks are the most widely used treatment — the mucilaginous bulk they create helps carry sand through the gastrointestinal tract. Psyllium is typically given via nasogastric tube as an initial loading dose, then continued orally for several days. Laxatives such as liquid paraffin may also be administered to facilitate passage of sand.

Intravenous fluid therapy is essential in horses that are significantly dehydrated or where gut motility is compromised. Pain relief using non-steroidal anti-inflammatory drugs (NSAIDs) such as flunixin meglumine helps manage discomfort while the bowel is cleared.

Surgical intervention is required in horses that fail to respond to medical management, or where there is evidence of bowel displacement or compromised vascular supply. The prognosis following surgery is significantly worse than for medically managed cases.

Prevention

Prevention is far preferable to treatment and relies on management changes that reduce ongoing sand ingestion:

Feed hay and hard feed from racks, nets, or solid rubber matting — never directly from the ground
Maintain adequate pasture cover to prevent horses grazing at soil level
Rotate paddocks to prevent overgrazing and bare patches
Consider regular psyllium supplementation (one week per month) for horses in high-risk environments — though evidence for this as routine prevention is mixed
Provide adequate fibre and forage to reduce pica behaviour
Ensure mineral supplementation to address potential deficiencies that may drive soil eating

Prognosis

Horses with mild to moderate sand accumulation treated early medically generally have a good prognosis. Recurrence is common if management practices are not addressed. Horses requiring surgery have a more guarded prognosis, particularly if bowel compromise has occurred. Chronic, heavily burdened horses can take weeks to months to clear their sand load fully.

When to Call the Vet

Call your vet immediately if your horse shows signs of abdominal pain, particularly if gut sounds are absent or reduced, the horse is unable to pass manure, or pain is unresponsive to walking or position changes. Any horse with recurrent colic episodes — even mild ones — warrants investigation for sand accumulation, as repeated low-grade episodes can indicate a building problem.

Frequently Asked Questions

How do I know if my horse has sand in its gut?

The sand settling faecal test is a useful home screening tool — place fresh droppings in a rectal glove, add water, and check for sand settling at the bottom after 15 minutes. However, this only detects sand being actively passed; a horse with a static large sand load may not show sand in faeces. A vet can confirm accumulation via abdominal radiography.

Is psyllium husk effective for clearing sand?

Psyllium husk is the most widely used treatment and has reasonable evidence supporting its use for clearing sand from the large colon. It works best when given via nasogastric tube in therapeutic doses rather than as a low-level daily supplement. Monthly psyllium supplementation as a preventive measure is commonly recommended but evidence for its routine use is less conclusive.

Can equine sand colic be fatal?

Yes. Severe sand impaction can lead to bowel displacement, rupture, or endotoxaemia, all of which can be fatal. This is why early diagnosis and treatment is critical. Sand colic that has progressed to require surgery carries a significantly higher risk of death than medically managed cases.

Which horses are most at risk of sand colic?

Horses kept on sandy coastal soils, horses on overgrazed pastures, horses fed on bare ground, and horses in drought-prone regions are at greatest risk. Horses with pica tendencies or mineral deficiencies are also more likely to actively ingest soil.

For further guidance, the British Equine Veterinary Association (BEVA) offers resources on colic prevention and management.