Written by Dr. Emily McNally, Rappahannock Equine Clinic. This article appeared in our Nov./Dec. 2014 Issue.

At is every horse owner’s nightmare to come outside to discover your horse acting uncomfortable. With the changing of the weather, impaction colic is something on everyone’s mind. Although it occurs at any time of the year, impaction colic is more prevalent during the fall and winter months due to a variety of factors affecting gastrointestinal motility and feed material makeup.

An impaction is caused by the blockage of the gastrointestinal tract of the horse by feed material. The intestinal tract of horses is very long and has multiple areas that narrow and make sharp turns before opening into larger segments. These areas are especially prone to blockages. A location called the pelvic flexure is one of these areas and is the most common site of impaction.

A blockage may take days to form and present itself. The buildup of feed material can go unnoticed until it gets large enough to cause abdominal tension. Pain usually starts as mild and intermittent. Horses are depressed and may spend more time lying down than usual. Horses often will paw, stretch, and look at their flank. An average horse passes 8–12 piles of manure per day. However, a horse with an impaction will have decreased or absent manure production. The manure that does pass is hard and dry or may be covered in mucus or fibrin strands.

The main idea behind treatment is providing pain relief while softening the impacted feed material. Overhydration with either oral or IV fluids increases the amount of water in the intestine, and oral laxatives can also be administered. Another important aspect of treatment is stopping a horse’s food intake. Eating more food may add to the size of the impaction. However, grazing for short periods can be done due to the high water content of grass and its laxative properties. Most impactions respond well to medical treatment, but surgical intervention may be needed if there is a concurrent problem or if the horse is unresponsive to medical treatment for over 24 hours.

colic horse

As the weather gets colder, it is important to be aware of impaction colic and the several ways you can reduce your horse’s risk of impaction. Probably the most important thing you can do as a horse owner is monitor water consumption. The more water your horse consumes, the less likely it will get impaction colic. Dry feed material is much more likely to get stuck in the intestines and cause a blockage. Similarly, a horse that isn’t drinking enough also isn’t producing enough saliva to properly soften and lubricate food. The average horse should consume 10–12 gallons per day to maintain hydration. Fresh, non-frozen water should be available at all times. Horses drink less water in the winter due to a variety of factors. Firstly, they do not like to drink cold water as much as warm water. As an owner, you should provide water at 40–60 degrees with the use of heating devices such as electric buckets, tank heaters, and insulated buckets. Similarly, horses don’t feel as thirsty in the winter because they are not exercising as much or losing as much to sweat as when the weather is warmer. Adding 1–2 ounces of salt to the grain ration can stimulate increased water consumption.

Exercise is essential to good gastrointestinal health and motility. Horses that moderately exercise are less likely to get impaction colic. If your horse is not being regularly ridden, you can at least ensure that it has adequate turnout. Confining it to a stall definitely can increase the incidence of impaction colic. Horses are very resilient to cold weather, and as long as the footing is good, a shelter is available, and they are getting increased calories from feed, horses can be turned out daily throughout the winter.

Proper dental care is another essential aspect in the prevention of impaction colic. Horses should all have their mouths inspected at least once a year by a veterinarian. Early detection of problems and correction by floating of teeth helps your horse adequately chew its food. When not chewed properly, hay is more likely to move slower and cause blockages. Similarly, parasite management is important in the maintenance of gastrointestinal health of your horse. A fecal egg count should be performed twice a year to discover the parasite load of your horse and adequately direct your deworming program.

Fall and winter can be beautiful seasons, and keeping your horse impaction free can make it even more enjoyable for you and your four-legged friends. If you have any questions, please call our office at 540-854-7171.