Q: I’ve always heard horses are more prone to impaction colic during winter, especially if they don’t drink enough water. Is this true? If so, what can I do to reduce my horse’s risk of impaction colic this winter?

A: At its most basic, colic is a term covering a wide variety of abdominal pain and can occur throughout the year. Impaction colic describes an incidence of colic related to a large bolus of feedstuffs or waste being caught (impacted) within the intestines. Impaction colic during the colder months is commonly associated with two dietary changes: an increase in the amount of dry feed consumed (especially hay) and a decrease in water intake.

A quick way to determine if your horse is consuming enough water is to routinely monitor his feces. If you notice dry, hard, and crumbly fecal balls, he is not drinking enough.

What Horses Are Prone to Impaction Colic During Winter?

Not all horses develop impaction colic during winter. Owners and managers can decrease their horses’ potential for the condition by monitoring diets, especially forage quality, water intake, and making sure fresh water is always available.

Horses evolved as animals that spend a significant amount of their time walking around and consuming forage. This almost constant movement helps keep the digestive tract moving feedstuffs and waste through, so we should make sure our horses get exercise. When storms or weather extremes arrive, we often believe putting our horses in stalls is in their best interest. However, researchers have shown equine gut motility significantly decreases the first few days after a horse moves inside for stall confinement, which can lead to an increase in impaction colic risk.

Improving Water Intake to Reduced Risk of Impaction Colic

The average adult horse consumes approximately 1 gallon of water per 100 pounds of body weight, or approximately 10 gallons if he’s a 1,000-pound horse. Horses need water for proper digestion and movement of feedstuffs through the digestive tract; the drier the feed provided, the more water the horse needs for the digestive tract to function properly.

In colder months, be certain your horse has water available that is not frozen. Some horses are willing to break a layer of ice if it forms on top of the water source, while others are more reluctant. Check your horse’s water sources several times each day to ensure they have not frozen. If your horse doesn’t want to drink very cold water, consider adding warm water (even from a thermos if you don’t have hot water in your barn) to bring up the water temperature in his buckets. You can also find ways to insulate buckets to help keep water from freezing if you cannot use heated buckets or trough heaters.

Top dressing either concentrate or flakes of hay with some loose table salt or other electrolytes can encourage a horse to drink. Soaking his feed and making a mash or slurry also incorporates more water into his diet. Although horse owners have historically used bran mashes, suddenly providing a feed like this can cause digestive upset or unbalance the diet. Now researchers discourage owners from feeding a true bran mash.

Take-Home Message

Keeping your horse hydrated is a key step to limiting his risk of impaction colic. Make sure the water you provide him is palatable and not frozen and be sure he has exercise opportunities to improve gut motility. Finally, check his hydration status daily to ensure he consumes enough water.

Do you have an equine nutrition question?