Small Colon Impactions

Disorders of the small colon make up a small percentage of the etiologies in acute abdominal crises in horses. Obstruction by fecal material, enteroliths, and meconium are the most commonly reported pathogenic conditions of the small colon in the horse. Treatment for small colon impactions consists of aggressive fluid therapy, gastrointestinal lubricants, laxatives, cathartics, standing enemas, anti-inflammatories, and analgesics. If surgery is required, it consists of the reduction of impacted small colons by emptying the small colon via enterotomy, or by a combination of lubricants and massage. The purpose of a study by William S. Rhoads, DVM; Michelle H. Barton, DVM, PhD; and Andrew H. Parks, VetMB, MS, was to characterize the treatment and outcome of horses treated medically and surgically for small colon impactions.

The study of 84 horses took place over a 10-year period, during which time 56 horses (67%) were admitted to a hospital between the months of October and February. Clinical signs of the horses admitted included 82% showing signs of colic (pawing, looking at flanks, laying down, rolling), 31% diarrhea, 30% anorexia, 12% straining to defecate, and 11% showing signs of depression.

Of the 84 horses, 37 were treated surgically and 47 were treated medically. No significant differences were identified for duration of clinical signs, physical parameters, and clinical pathology values between the two groups. However, a significant difference was identified for duration of hospitalization between the two groups. The average stay in the hospital for horses treated medically was 7.23 days, while those treated surgically stayed 10.7 days.

The most common complications occurring during hospitalization included diarrhea, jugular thrombophlebitis or swelling at the catheter site, recurrent colic, fever, and laminitis.

At the end of treatment, and upon follow-up--a mean time of 36.8 months for medically treated horses and 35.5 months for surgically treated horses--89% of the medically treated horses were alive and being used for their intended purpose. In the surgically treated group, 91% were alive and being used for their intended purpose.

In conclusion, the majority of the horses admitted for small colon impactions occurred during the fall and winter months. In this study, diarrhea was both a common clinical sign and complication of impaction of the small colon. The transrectal exam included finding loops of firm small colon or running into a wall of impacted feces.

Aggressive medical management should be instituted early in horses suspected of having a small colon impaction. The severity of pain, response to analgesics, and abdominal distention are important factors in the decision for surgical intervention. In this study, the long-term prognosis for horses treated both surgically and medically is good.

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at or by calling 800/582-5604.

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