Colic in horses is not a single disease but a broad term for abdominal pain, most often originating in the gastrointestinal tract. It is the leading cause of emergency veterinary calls in horses, and its severity ranges from mild cramping that resolves on its own to life-threatening intestinal blockages or twists that require surgery. Understanding the types, signs, and basic management of colic can make the difference between a routine episode and a fatal one.
Why Horses Are Prone to Colic
A horse’s digestive system is unusually long and complex, with roughly 70 feet of intestine suspended loosely inside the abdomen. Unlike cattle, horses cannot vomit, so anything that enters the stomach must pass all the way through. This one-way system means that gas buildup, blockages, or displaced intestine has no easy escape route, and pain develops quickly.
The most common forms of colic fall into a few categories. Spasmodic colic involves painful intestinal cramping, similar to gas pains in people, and often resolves with minimal treatment. Impaction colic occurs when a mass of dry feed or foreign material (like sand) lodges in the intestine and stops moving. Gas colic results from excessive fermentation and distension in the gut. Displacement or torsion colic, the most dangerous type, happens when a section of intestine shifts out of position or twists on itself, cutting off blood supply.
Common Causes and Risk Factors
Diet is the single biggest controllable risk factor. Sudden changes in feed type or amount, too much grain relative to forage, and irregular feeding schedules all disrupt the microbial balance in the hindgut. The American Association of Equine Practitioners recommends that at least twice as much of a horse’s energy come from roughage (hay or pasture) as from concentrates like grain. Large grain meals are particularly risky because they can overload the digestive tract; splitting daily concentrate rations into two or more smaller feedings reduces this load.
Dehydration is another major trigger. Horses that don’t drink enough water produce drier intestinal contents, which move more slowly and are more likely to form impactions. Cold weather, dirty water troughs, and electrolyte imbalances all reduce water intake.
Parasites cause several distinct forms of colic. Tapeworms that attach to the walls of the cecum and ileum can cause mucosal damage ranging from mild redness to necrotic ulcers, leading to intestinal spasms, impactions, and even intussusception (where one segment of bowel telescopes into another). A roundworm called Strongylus vulgaris migrates through intestinal arteries, damages vessel walls, and can trigger blood clot formation that cuts off blood flow to sections of gut. In young horses, heavy ascarid (roundworm) burdens can physically block the small intestine; the median age for ascarid-related impaction is just five months. Small strongyles (cyathostomins) cause problems when large numbers of encysted larvae emerge from the intestinal wall simultaneously, triggering sudden, profuse watery diarrhea and severe dehydration.
Sand ingestion is a concern in regions with sandy soil, especially when horses eat off the ground. Sand accumulates in the colon over time, irritating the lining and eventually forming heavy impactions. Stress also plays a role. Horses experiencing changes in environment, transport, or workload are at higher risk of intestinal dysfunction.
Recognizing the Signs
Horses in pain cannot tell you what’s wrong, but their behavior changes in recognizable ways. The most common signs of colic include:
- Pawing repeatedly with a front foot
- Looking back at the flank or biting at the sides
- Curling the upper lip and arching the neck
- Kicking at the abdomen with a hind leg
- Lying down and rolling from side to side
- Sweating unrelated to exercise or heat
- Stretching out as if trying to urinate
- Straining to defecate or producing fewer droppings than normal
- Loss of appetite and general depression
- Visible bloating of the abdomen
Mild episodes often involve stretching and restlessness. Severe colic typically produces violent rolling, profuse sweating, elevated heart rate, and an inability to stand comfortably. A horse that repeatedly throws itself to the ground or shows no response to pain relief is in a medical emergency.
What to Do Before the Vet Arrives
Remove all feed immediately. Adding more food on top of a possible impaction will only make things worse. Your veterinarian will likely recommend withholding grain and hay until the horse passes manure and the episode resolves. A small amount of fresh grass grazing may actually help stimulate gut movement, but grain and hay should stay off limits.
Walking the horse can provide pain relief and encourage intestinal motility, particularly if the colic involves cramping or gas. It also helps prevent violent rolling, which carries a small risk of intestinal displacement. That said, never walk a horse to exhaustion, and stop if walking seems to make the pain worse. Conditions that mimic colic, such as laminitis (foot inflammation), tying up (muscle cramping), or rib pain, will worsen with forced movement.
Note the horse’s vital signs if you can safely do so. Heart rate, breathing rate, gum color, and the presence or absence of gut sounds are all useful information for your vet. A quiet abdomen with no gurgling is a warning sign, often associated with a shutdown of normal intestinal movement or compromised blood flow.
How Vets Diagnose the Cause
A veterinarian’s initial assessment combines a physical exam with targeted diagnostics. Common procedures include passing a nasogastric tube through the nostril into the stomach to check for fluid accumulation (a sign that the intestine is backed up), a rectal exam to feel for displaced or distended intestine, and an abdominal ultrasound to visualize gut wall thickness, fluid, and intestinal position. Blood work helps assess dehydration and organ function.
In some cases, the vet may perform abdominocentesis, drawing a small sample of the fluid surrounding the intestines to check for signs of infection or dying tissue. Radiographs are used selectively to look for sand accumulation or enteroliths (mineral stones that form in the colon over months or years). For sand colic specifically, horse owners can perform a simple fecal float test at home: mix a standardized amount of manure with water, let it settle, and check the bottom of the container for sand.
Treatment and Surgical Outcomes
Most colic episodes, particularly gas and spasmodic colic, resolve with pain management, fluids, and time. The vet may administer anti-inflammatory medication and intravenous or oral fluids to rehydrate the gut contents and get things moving again. Impactions sometimes require repeated doses of fluids through the nasogastric tube, along with laxatives, over 24 to 48 hours.
Surgery becomes necessary when the intestine is twisted, severely displaced, or when a blockage won’t resolve with medical treatment. The prospect of colic surgery is understandably daunting, but outcomes have improved considerably. In a retrospective study of 134 horses that underwent colic surgery, 79% survived to hospital discharge. Among those followed for a year afterward, the long-term survival rate was 86%. Perhaps most reassuringly for owners of performance horses, 76% of surviving horses returned to their previous or intended function, whether athletic competition or breeding, and 72% were reported to be athletically active at one year.
Speed matters. A horse whose compromised intestine loses blood supply for too long faces tissue death that no surgeon can reverse. Early veterinary involvement dramatically improves the odds.
Practical Prevention Strategies
Colic can never be eliminated entirely, but consistent management reduces the risk substantially. The AAEP’s core recommendations center on routine and diet:
- Keep a consistent daily schedule for feeding, turnover, and exercise. Horses are creatures of habit, and disruptions stress their digestive systems.
- Prioritize forage over grain. Hay should be the foundation of the diet, ideally fed free-choice. When grain is necessary, divide it into two or more small meals rather than one large one.
- Provide fresh, clean water at all times. In cold months, consider a heated water source to encourage drinking.
- Avoid feeding on sandy ground. Use feeders, mats, or troughs to keep hay and grain off the soil.
- Maintain a regular deworming program designed with your vet, ideally based on fecal egg counts rather than a blanket schedule.
- Change exercise intensity gradually. Sudden increases in workload stress the gut just as sudden feed changes do.
- Inspect hay and pasture for toxic plants, blister beetles, and foreign material.
- Minimize stress during travel and environment changes. Horses at shows, new barns, or during transport are at elevated risk and deserve extra monitoring.
Regular dental care also plays a role. Horses with sharp or uneven teeth chew poorly, swallowing larger feed particles that are harder to digest and more likely to cause impactions. Most horses benefit from a dental exam at least once a year.