Equine Colic Types

Impactions – stomach and small intestine

Impaction pathophysiology

Common sites of impaction (intestinal blockage due to feed material) include the pelvic flexure, the ileum, the cecum, the small colon and the stomach. Ascarid impactions are typically in the jejunum.

Gastric impactions

Gastric impactions in horses, a review. The Horse, 2011

She added that the condition is caused by a variety of factors including the consumption of certain feeds that swell after ingestion, dental problems that diminish the horse’s ability to chew feed properly, inadequate water supply, excessively rapid eating, and pathophysiological disturbances (changes in the horse’s normal mechanical, physical, and biochemical functions).


Ascarid impactions

Ascarid impactions can occur after deworming when the dead and dying worms create an obstruction.

  • 4-24mo old
Clinical signs
  • Unthrifty
  • Mild-moderate colic
  • Reflux
  • Worms in reflux
  • Ultrasound- worms may be visible
  • Signs of intestinal blockage
  • Peritonitis
  • Adhesions
  • Intestinal rupture
  • Surgery with enterotomy
Risk factors
  • Deworming with an effective agent in an infected foal (large die off)
  • Poor
  • Deworm with less effective product first (strongid, 1/2 dose fenbendazole
  • Treat with mineral oil at time of deworming



Ileal impactions and ileal hypertrophy

Ileal impactions occur most often with Bermuda grass hay and parasite issues.

  • Arabs, mares for ileal impactions
  • >5 yo for ileal hypertrophy
Clinical signs Ileal impaction

  • worsening colic
  • reflux

Ileal hypertrophy

  • recurrent colic
  • partial anorexia
  • weight loss
  • Rectal: SI distension, early on – doughy tubular mass
  • Transrectal ultrasound: SI distension
  • Differentials: strangulating lesions, PDJ
  • Gastric rupture
  • Iv fluids with analgesics
  • Intraoperative massage, lubrication
Risk factors
  • SE USA
  • feeding low quality Bermuda grass hay
  • Sept-Nov
  • tapeworms
  • Good. Reimpaction is rare
  • Avoid Bermuda grass hay
  • Deworm for tapeworms




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Large Animal Surgery - Supplemental Notes Copyright © by Erin Malone, DVM, PhD is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.