Ask the Veterinarian: Colic

By Dr. Hannah Weimer

Question:  We’ve had several horses colic at my barn recently.  What causes this and is there anything I can do to prevent my gelding from getting it?

Answer: That’s a great question and something that most horse owners have dealt with at one time or another.To start, colic is a term used to describe any sort of abdominal pain in horses. It is one of the most common emergencies I see as an equine veterinarian, and anyone who has been around a colicking horse can attest to the fact that even a mild case can be stressful on all involved.  Though the exact reason why a horse colics is often undetermined, the common denominator is that the horse has a large complex GI (gastrointestinal) tract that is susceptible to a variety of issues.

Since horses can’t tell us that their stomach hurts, often the first sign they show is a reluctance to eat and a generalized quiet or depressed manner, which may manifest as lying down for long periods of time. As their discomfort escalates, they become increasingly irritated and may show signs such as pawing, circling their stall, getting up and down frequently, and rolling excessively.  During this period, they often become tachycardic (increased heart rate) and tachypneic (increased respiratory rate) and may sweat markedly.

The mechanisms of a colic episode can range from simple gas colic, where excessive gas results in distension of the bowel, which causes discomfort, to something more complex like a twist in the large colon.

Colic lesions fall into two broad categories, strangulating and non-strangulating.  Non-strangulating lesions include the gas colic mentioned above as well as displacements of the large colon and impactions of the GI tract. Since the horse’s colon is minimally adhered to the body wall, it can become displaced into either the right or left abdomen where it may become entrapped, disrupting the normal flow of the digestive process.  

Impactions of the GI tract also fall into the non-strangulating category, and while they most commonly occur in the pelvic flexure of the large colon, stomach, small intestinal and even cecal impactions can also occur. While all of these non-obstructive disorders can be painful and even life threatening, they do not generally impede the blood flow to the intestines like strangulating lesions. 

Strangulating lesions include twists or torsions of both the large and small intestine, along with other disorders that compromise the blood flow to the bowel.  These lesions tend to be dramatically more painful than non-strangulating lesions; to cause the horse to become systemically ill much faster; and all require immediate surgery for a positive outcome, as the compromised blood flow can rapidly lead to necrosis and death of the affected segments of bowel.

Determining the nature and seriousness of a colic episode is where veterinarians come in. A thorough physical exam is essential to establish how serious the colic condition the horse is.  Parameters such as heart rate, respiratory rate, and temperature, as well as auscultating gut sounds and observing mucus membrane color, are invaluable in assessing their health status.  Other procedures such as nasogastric intubation and rectal exams also provide baseline information, including whether a gastric outflow problem is present and if abnormalities such as large colon impactions or displacements, excessive gas distension, ordilated small intestine are present.

Treatments like intravenous fluids and anti-inflammatory and pain relieving medications may be administered at any time during the work up. Depending on the results of these initial procedures and your horse’s behavior, it may be recommended that he be referred into a clinical setting where further diagnostics, such as blood work, abdominal ultrasonography, or an abdominocentesis can be performed.  Unfortunately, even with every diagnostic test available, we are unable to definitively diagnose most lesions without physically entering the abdomen. So your horse’s response to treatment and overall pain level are the strongest indicators as to whether surgical intervention is needed.

Though there is no magic remedy that prevents all colic, there are certain management strategies that have been shown to reduce the incidence of certain types of colic.  Especially as the winter months approach, impaction colics become a bigger concern, because as the temperature drops, horses tend to drink less water and thus become mildly dehydrated.  This, coupled with increased reliance of dry forages to round out diets as pasture grasses diminish, leads to an overall drying out of the intestinal contents, increasing the chances of an obstruction forming. Management strategies such as administering electrolytes and making warm water available at all times during the winter will encourage drinking and help to prevent impactions. 

Stall confinement has also been linked to large colon impactions, so ensuring adequate turnout is essential, as is maintaining proper dental health so that your horse is able to chew effectively. 

While proper management pays dividends, the most important factors in safeguarding your horse are to be observant, recognize when something is wrong, and to involve your veterinarian early on to prevent a small problem from becoming a larger one in the future. 

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