Enterolithiasis
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Enteroliths are mineral concretions that form around a small core of material within the horse’s large colon. Layers of minerals, commonly magnesium ammonium phosphate, accumulate over time and create smooth round, oval or irregular stones. A horse may carry one or several enteroliths for years. Disease develops when a stone intermittently obstructs a narrow section of colon or becomes firmly lodged, preventing gas and ingesta from passing.
Clinical signs often consist of repeated colic episodes that resolve and return as the stone moves. Appetite may fall, manure production may decrease and abdominal distension can develop. Complete obstruction causes severe persistent pain and progressive cardiovascular compromise. An enterolith can also press on the intestinal wall and contribute to ulceration or, less commonly, rupture. Signs do not distinguish it reliably from impaction, displacement or another obstructive lesion.
Enterolithiasis is especially recognised in regions and management systems where horses consume diets and water that favour mineral precipitation. Breed susceptibility has been reported in Arabians and some related or regional populations. Diets high in alfalfa, certain mineral concentrations and reduced large-colon acidity have been proposed as contributors, but no single ration feature explains every case. The long formation period means recent management changes may be unrelated.
Small enteroliths occasionally pass in manure, but clinically obstructive stones usually require surgical removal. Delay after complete obstruction risks colon damage, endotoxaemia and rupture. A successful operation often has a good prognosis when the bowel remains viable. Enteroliths are not intestinal parasites and cannot be removed with routine deworming. Finding one stone does not guarantee that no others are present, so the entire accessible large colon must be evaluated during surgery and the horse’s longer-term dietary and regional risk reviewed afterwards.
Screening & Early Detection
Routine blood testing does not screen for enteroliths. Recurrent unexplained colic in a horse living in or originating from a high-risk region should increase suspicion. Owners should document episode frequency, duration, manure changes, diet history and whether close relatives or stablemates have been affected. Passing a small stone in manure is important evidence and should prompt veterinary discussion even if the horse appears comfortable.
Abdominal radiographs can identify many enteroliths because of their mineral density, but visibility depends on stone composition, size, location, equipment and the horse’s body size. A negative radiograph therefore does not exclude the condition. Rectal examination, ultrasound and routine colic tests may identify obstruction or distension without showing the stone itself. Laboratory changes generally reflect dehydration and compromised intestine rather than confirming enterolithiasis.
Persistent pain, repeated colic with decreasing intervals, marked gas distension or failure to respond to medical treatment warrants surgical referral. When complete obstruction is suspected, definitive diagnosis may occur during abdominal exploration. Screening should not be replaced by repeatedly treating presumed gas colic without investigating the pattern.
Treatment & Management
A horse with suspected enterolith obstruction receives colic stabilisation, including analgesia, intravenous fluids and gastric decompression when needed. Medical treatment may relieve temporary spasm around a mobile stone, but it cannot dissolve or reliably remove a large mineral concretion. Persistent obstruction, escalating pain or colon distension requires abdominal surgery.
During surgery the colon is exteriorised where possible, and the enterolith is removed through a controlled enterotomy. The surgeon examines accessible bowel for additional stones and checks the obstruction site for pressure damage, devitalisation or rupture. Contaminated abdominal surgery requires careful lavage and antimicrobial planning. Severely damaged colon or widespread contamination worsens prognosis, which is why referral before systemic collapse is important.
Postoperative management includes fluids, pain relief, gradual refeeding, incision care and surveillance for ileus, diarrhoea, infection and laminitis. Exercise is restricted while the abdominal incision heals. After recovery, the veterinarian and nutrition professional may review forage type, mineral balance, water and regional risk. Reducing excessive alfalfa or correcting an imbalanced ration may be appropriate for some horses, but drastic dietary restriction is not justified without analysing the complete diet. Surgery removes existing stones; it does not guarantee that new enteroliths cannot form, so recurrent signs still require investigation.
Breeds or species affected
Arabian
Open horse breed description, care requirements and conditions
Shagya Arabian
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American Quarter Horse
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Morgan
Open horse breed description, care requirements and conditions
American Saddlebred
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Miniature Horse
Open horse breed description, care requirements and conditions