Conditions or ailments that are the cause of a problem that you see - your observation.

Your vet may diagnose

Large Colon Impaction, Pelvic Flexure Impaction


Large colon impaction is a common cause of colic that doesn't respond to field treatments. Often, a horse with large colon impaction has been treated with routine field treatments and has returned to colic signs.

Rectal palpation reveals this classic problem- a firm hard mass palpable in the pelvic flexure of the colon, which a vet feels on the left side of the horse.

This hairpin, narrow turn is an area commonly affected and happens to be easily reachable on a rectal exam.

The problem is more commonly diagnosed in older horses and those with dental conditions that cause them to grind hay improperly. We tend to see this problem more commonly in the winter during cold periods. This is likely because horses are not drinking as much water. In addition, horses undergoing stresses of various kinds, and those with other health problems, are more likely to develop this problem.

Horses eating coarse feeds, those that are have other illnesses, those that are confined, and those that experience dehydration are also thought to more commonly acquire this problem.

Repeated incidents of this problem may indicate a colon motility disorder.

DIAGNOSIS is through rectal examination.

TREATMENT is usually medical- nasogastric and intravenous fluid therapy to soften the impaction, improve intestinal function, and hopefully allow the horse to break down the impaction and move it down the tract.

my vet's role


Prognosis is fair to good with prompt diagnosis and appropriate treatment. Some cases do not respond to even aggressive medical treatment, and will require surgery.

my role


I might observe

You might make these observations when a horse has this condition.

Very Common
Less Common
more observations

Questions To Ask Your Vet:
  • What are the chances for success with this treatment?

Know that this problem occurs more frequently in older and debilitated horses, and during cold snaps. Be on the lookout for it.

Maintain adequate water supply especially during cold weather. Consider providing your horse with heated water during cold weather. Follow all husbandry and general management recommendations to reduce colic incidence.

further reading & resources

Author: Doug Thal DVM Dipl. ABVP