Calculate your horse’s colic risk

EQUUS' 7-question survey can tell you your horse's chances of developing colic, as well as what you can do to protect his health.

Maybe you never thought about your horse’s colic risk before. After all, he never passes up a meal. In fact, at dinnertime he is always the first one at the pasture gate. Once in his stall, he never fails to position himself right at the feed tub. So when he turns up his nose at his nightly ration and begins pacing in his stall, you know right away that something’s wrong. When the veterinarian arrives and examines your horse, your suspicions are quickly confirmed: It’s colic. Fortunately, however, it’s a mild case, and medication brings swift and lasting relief.

A horse lying down in the dirt
Colic is blanket term for pain in the belly that can be the result of a variety of causes.

But after the crisis has passed, you are left with questions: What caused the colic and could it have been prevented? Is it likely to happen again? Will it be worse the next time? Colic, a blanket term describing pain in the belly, is an ever-present worry for horsekeepers. It’s not as mysterious and scary as some of the mosquito-borne viruses that garner so much public attention, but colic claims innumerable equine lives each year.

The science of risk assessment

Researchers and practicing veterinarians have been working to understand colic for decades. And great strides have been made in diagnosis and treatment of digestive disorders in horses. Perhaps most important for horsekeepers, however, has been the work of epidemiologists, who focus on disease occurrence and distribution. By investigating actual cases, epidemiologists can make inferences about environmental, physiological and lifestyle factors that contribute to colic. With this information, it’s possible to construct a real-world assessment of risk factors and possible remedies.

So where does your horse stand? To help you find out, we’ve put together a short quiz based on the latest findings of colic researchers. Answer each question and tally up the points at the end. The “score” will not only provide a rough estimate of your horse’s colic risk but will also indicate whether you need to make some management changes. The “best” answer to some of these questions may not be possible for your horse, but you may be surprised at how minor adjustments in your management practices can protect his health.

1. Has your horse been diagnosed with colic before?

a. Never (0 points)

b. One or two mild episodes that required no treatment (2 points)

c. At least one episode that required veterinary attention (4 points)

d. At least one episode that required surgical treatment (10 points)

No one knows exactly why, but horses who’ve had colic seem to be at an increased risk of a repeat episode. In fact, studies suggest that these horses may be five to six times more likely to develop colic, and certain types of digestive problems, such as large colon impactions, have a particularly high recurrence rate. Several other factors may be involved, including lack of turnout, inadequate water intake or the presence of an underlying physical problem that has not been diagnosed or treated.

How a horse’s colic was resolved also is a predictor of his future health. A horse who required surgery is at a higher risk of colic than one whose condition was resolved with medication alone. The residual effects of surgery–bands of scar tissue left from incisions–can constrict the intestines or prevent the gut from moving freely.

2. Which description best fits your horse’s diet?

a. Access to free-choice grazing at all times (0 points)

b. Access to hay at all times (0 points)

c. Three or fewer grain meals a day and supplemental grass and/or hay (5 points)

d. Two to three grain meals plus free-choice hay or pasture (3 points)

Extra: If hay is supplied from a round bale add 3 points to your score.

The equine digestive tract is designed for the slow, steady intake of forage. Hay and other fibrous forage is largely digested in the hindgut while the starches in grains are normally broken down in the small intestine. If a horse eats a large grain meal, however, his digestive system may be overwhelmed by the starch “spillover.” When this occurs, excess undigested carbohydrates pass from the small intestine into the hindgut, where bacteria that normally ferment fiber begin to digest the starch molecules. The resulting surge of activity produces high levels of acid and alcohol that kill the resident bacteria, which causes the release of dangerous toxins. The result can be colic and, in some cases, laminitis.

The best way to avoid this potentially devastating chain of events is to offer your horse free-choice fibrous forage and feed him the lowest amount of starchy concentrated feed that he needs. (Most pleasure horses who have access to good pasture and hay need no grain at all.) Stick to clean, somewhat green, fine-stemmed grass hay, and if you must feed grain to maintain your horse’s weight or to fuel performance, try breaking his ration up into four or more smaller meals fed over the course of the day and evening.

High-fat feeds are another alternative, and small amounts of fat–corn oil is particularly palatable–can be substituted for grain as a source of calories. Fat contains 2.25 times more calories than the same weight of carbohydrates; one cup of corn oil is roughly equivalent to about 1.4 pounds of sweet feed. Unlike starch, undigested fat passes through the large intestine without affecting the gut flora. Several feeds formulated with a higher fat content are on the market, or you can top-dress your horse’s grain meal, working up to as much as two cups of corn oil a day.

3. Have you made any changes to your horse’s diet in the last 14 days?

a. No (0 points)

b. Yes, I made a gradual change in grain ration over the course of two weeks. (0 points)

c. Yes, I changed his grain ration over two day’s time. (3 points)

d. Yes, I changed his grain ration between feedings. (7 points)

e. Yes, I offered my horse a different type of hay or moved him to a new pasture. (3 points)

Dietary changes, particularly those that involve introducing large concentrated grain portions (four pounds or more per “meal”), have been associated with an increased risk of colic. When increasing or altering your horse’s grain consumption, make changes gradually, with incremental additions or modifications taking place over a period of five days or more. If you are switching to a new type of grain, for example, start by mixing a quarter-portion of the new feed with three-quarters of the old ration for three days. Continue to increase the proportion of new grain by one quarter every two to three days until the new feed has replaced the old one.

An incremental approach is equally important when switching to a new type of hay and when introducing horses to a different pasture, particularly lush or newly seeded fields.

4. Which scenario best describes your horse’s living arrangements?

a. Continuous turnout with free-choice grass or hay (0 points)

b. Roughly 12 hours in a stall and 12 hours of turnout (3 points)

c. Most of the day in his stall with a few hours of turnout each day (7 points)

d. Stabled with access to a corral or pen (5 points)

e. Stabled except for riding or brief exercise (9 points)

Several studies have shown a correlation between increased turnout time and reduced colic incidence. Time spent in fields or pastures provides horses with plenty of grazing opportunities; in addition, some experts believe that the ability to wander around a pasture is beneficial because it helps to keep a horse’s coarser, bulkier intestinal contents mixed and moving.

Conversely, research suggests that the more time a horse spends stabled, the greater his risk of colic. Though it was not a controlled experiment, a 1995 retrospective study noted that a large proportion of horses with large colon impaction had been confined to their stalls because of major injury or surgery in the two weeks before showing clinical colic signs.

Another study in the early 1990s found that horses turned out on pasture around the clock had the least chance of experiencing intestinal distress, while those confined for less than 12 hours colicked less than those stabled for more than 12 hours.

5. How often and seriously does your horse compete?

a. Not at all (0 points)

b. Occasionally, at local events (0 points)

c. Fairly frequently, with moderate to intensive training each week (2 points)

d. Frequently, with intensive training based on competition schedule (3 points)

Research suggests that elite equine athletes–racehorses and show horses in active training or competition–have a higher colic risk.

These horses often receive the very best of care, of course, but their lifestyles often incorporate elements known to place stress on the delicate equine digestive system: frequent transport, high-energy feed, demanding exercise regimens and limited turnout.

6. How is your horse’s dental care managed?

a. Annual or biannual checkup and care as needed (0 points)

b. Dental care is provided when there appears to be a problem (1 point)

c. No dental care at all (2 points)

It has long been assumed that regular dental care that keeps a horse’s teeth healthy and his bite solid will translate into better-chewed food and improved digestion. Now a study seems to back up this assumption. Researchers found that horses who had more frequent dental examinations had a lower incidence of simple colonic obstruction colic or distention (constipation).

7. Who provides the primary care for your horse?

a. I do (0 points)

a. I do (0 points)

b. My friend cares for my horse at her place. (0 points)

c. Staff at the boarding facility where he is kept (1 point)

d. My horse lives out with a herd that is not managed on a daily basis. (0 points)

Many boarders dream of keeping their horses on their own property. And research suggests that, beyond convenience and enjoyment, there may be another reason to bring your horse home–to keep him healthier.

At least two studies have indicated that horses who are cared for by their owners have a decreased risk of colic. This could be true for a number of reasons: The owner has the most at stake and may provide more consistent care with fewer day-to-day changes. Plus, most home horsekeepers also have fewer horses per acre than commercial facilities and can devote more time to observing each animal.

Of course, home horsekeeping is not possible for everyone. If you can’t keep horses on your own property, take heart: At a busy boarding or training facility there are often people on hand during most of the day to keep a closer eye on each horse’s condition.

Tally it up:

5 points or less: You are doing just about all you can to protect your horse from colic. Keep up the good work!

From 6 to 16 points: You could probably change or two aspects of your horse’s feeding or turnout programs, but you’re on the right track.

17 points or more: Your horse may never colic, but his lifestyle puts him at significant risk, and you may want to make some practical management changes. The tendency to colic is greatest when you restrict a horse’s exercise and offer him starchy feeds. 

If your situation prevents you from providing more turnout or making other significant changes, try to limit and/or evenly distribute the energy density in your horse’s diet and use exercise to compensate for any constraints associated with where and how you live. For example, take your horse for a daily walk and put round rocks in his feed tub or place his grain on his hay to stretch out his eating opportunities. You’ll find that while you improve your horse’s health, you also enhance the quality of his life. 

Note: If your horse has had colic surgery, you were destined to score high on this quiz. You can’t erase your horse’s medical history, but knowing the risks may help you head off another colic episode with dietary or turnout changes. 

If you have any questions, contact your veterinarian to assess which management practices may predispose your horse to colic. 

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