Researchers at the University of Liverpool in the United Kingdom set out to answer the question of whether the time of year/season has an effect on the number of colic cases.

Using sophisticated statistical methods, they examined the university’s colic case files dating back to 1991. As you might expect, strangulation of the bowel by the stalk of a lipoma—fatty tumors that hang on a long stalk and may become wrapped around the bowel like a bolero—showed no seasonal pattern. However, a clear fall/winter peak was found for impactions, spring for equine grass sickness (a problem in the United Kingdom likely associated with exposure to the bacterium that causes botulism), and with peaks in both the spring and fall for all other types of colic.

Impaction is most likely during the winter, probably due to a decrease in water consumption.

Management factors were not specifically analyzed in this study, but the authors did discuss how their findings might tie in with those of other studies that did look at management. These aspects included more time spent in a stall, reduction in level of exercise and/or turn out and change of diets either higher or lower in roughage.

As a corollary to this, we would point out that reduction in grass consumption and substitution of hay for grass greatly reduces the amount of water the horse is taking in while eating. Grass is 80+% water, while hay is about 10%. The authors also discussed a possible link between bad weather and colic, but stated it would be difficult to separate out whether it was the weather per se or the fact that horses are more likely to be stabled during bad weather.

This study drives home some basic and well-known-truths regarding feeding and management as they apply to avoid colic, specifically:

1. Make all changes in diet gradually, including both concentrates and hay, to give the intestinal tract a chance to adapt. Make substitutions over a period of a minimum of four days, preferably 14 days.

2. An unlimited supply of clean, fresh water should be available at all times and especially when horses are consuming hay.

3. Exercise is extremely important to normal functioning of the intestinal tract. A  switch from turnout to stall confinement and from grass to dry hay puts the horse at particularly high risk for colic.

When real life intervenes (hay shortages, drought, horse moved to a new location with little or no pasture, turnout or riding must be cut back), there are some measures you can take to try and minimize risk:

1. Add salt directly to the feed to encourage good drinking. Use a minimum of 1 oz. (2 tablespoons) of table salt in the winter, 2+ ozs. in the summer, divided between feedings.

2. Hang an extra water bucket.

3. Consider pre- or probiotic use (we recommend using Ration Plus) if an abrupt change in hay or grain cannot be avoided.

4. If time for riding or turnout is at a premium, at least longe the horse for 20 to 30 minutes/day—or pay someone else to do it.

For details and more tips, see our upcoming article on Digestive Aids.