A large colon resection is a surgical procedure in which a portion of the large colon is removed due to severe disease or irreversible damage. The large colon plays a critical role in fermentation, water absorption, and manure formation. When a section becomes non-viable (dead or irreversibly damaged), surgical removal may be necessary to save the horse’s life.
Large colon resection is most commonly performed as an emergency procedure for:
- Severe large colon volvulus (twisting)
- Strangulating obstruction
- Infarction (loss of blood supply)
- Irreparable displacement with compromised blood flow
This procedure is performed under general anesthesia at a surgical facility by an ACVS board-certified veterinary surgeon, most often during emergency abdominal exploration due to severe colic signs.
In select cases, large colon resection may be performed electively rather than as an emergency. Elective resection may be considered for horses with:
- Recurrent large colon displacement
- Persistent colon dysfunction or motility disorders
- Focal colon disease identified during prior surgery
Elective procedures are performed when the horse is stable and not systemically compromised. Because the surgery is planned rather than emergent, horses may be better optimized prior to anesthesia, and surgical risk may be reduced compared to emergency cases.
The goal of elective resection is to reduce the risk of future life-threatening colic episodes in carefully selected horses. Your surgeon will discuss whether this option is appropriate based on your horse’s history and overall health.
Conditions requiring emergency large colon resection typically present as severe, acute colic.
Clinical signs may include:
- Sudden onset of severe abdominal pain
- Uncontrollable pain signs, despite sedation and analgesia
- Repeated rolling or violent thrashing
- Elevated heart rate (often >60–80 beats per minute)
- Sweating
- Depression
- Marked abdominal distention
- Reduced or absent manure production
- Poor response to medical treatment
Rapid deterioration is common in cases involving compromised blood supply and severe gas distension.
Your veterinarian will perform a thorough examination and assess severity.
Physical examination may include:
- Heart rate, respiratory rate, rectal temperature
- Mucous membrane color and capillary refill time
- Gastrointestinal sounds
- Rectal examination (may reveal distended or displaced colon)
Additional diagnostics may include:
- Passing a nasogastric tube
- Blood work (lactate levels may indicate tissue compromise in emergency cases)
- Abdominal ultrasound
- Abdominocentesis (evaluation of abdominal fluid)
The necessity to proceed to emergency colic surgery is often mandated by severity of colic signs and uncontrollable pain. A definitive determination that colon resection is required is often made during exploratory surgery, when the surgeon evaluates tissue viability directly.
Emergency surgical intervention is required when the colon is non-viable.
Surgical treatment includes:
- Exploratory laparotomy under general anesthesia
- Identification and replacement of colon lesion
- Removal (resection) of non-viable tissue
- Reconnection (anastomosis) of the remaining healthy colon
In some cases, extensive damage may make surgical correction impossible. Your surgeon will assess prognosis and likelihood for a successful resection outcome during the procedure. In elective resection cases, colon viability is good and therefore outcome is improved.
Horses undergoing large colon resection require intensive postoperative care, including:
- Hospitalization for 7–10 days or longer
- Intravenous fluids
- Broad-spectrum antibiotics
- Pain management
- Monitoring for postoperative ileus (delayed transit), endotoxemia (bacteria in body systems other than the colon), or incisional complications
Feed is gradually reintroduced once gastrointestinal motility returns.
After discharge, horses generally require:
- Strict stall rest initially based on incisional healing
- Gradual increase in turnout
- Typically 3 months or more before return to riding
Long-term dietary management may be recommended depending on the amount of colon removed and the reason for surgery. Most horses transition from a ‘low bulk’ diet of chopped hay and pelleted complete feed to a normal diet over 6-12 months post operatively.
Prognosis depends on:
- The underlying cause of colon damage
- Degree of systemic compromise prior to surgery
- Extent of colon removed
- Presence of postoperative complications
Elective resections performed in stable horses may carry a more favorable prognosis than emergency cases involving shock or endotoxemia.
Advances in surgical technique and postoperative care have improved survival rates; however, large colon resection remains a major procedure and prognosis varies case by case.
Horses that recover without major complications may return to full athletic function.
Key Points for Horse Owners
- Severe colic with abdominal distention is an emergency
- Rapid referral improves survival in emergency cases
- Colon viability can only be definitively assessed during surgery
- Elective resection may be considered for carefully selected horses with recurrent colon disease
- Intensive postoperative care is critical to recovery
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