By Eleanor Kellon, VMD, staff veterinary specialist for Uckele Health & Nutrition

Colic can strike at any time and has many known–and some not-so-well-understood–risk factors. The fall and winter seasons themselves are known risk factors and there are several things you can do to decrease your horse’s likelihood of developing colic. As pastures dwindle in the fall and the horse must switch to a different diet, two major factors are at play. One is the fact there is a different diet. The other is change in moisture level of the diet.

Most owners know they should transition slowly when adding or changing grains and other concentrates. However, it is important to realize that a change in forage, including hay types, should also be made gradually. This is because the protein, sugar, and starch components of hay are digested in the small intestine and–while digestive enzymes there can successfully adjust to changes–it doesn’t happen overnight.

Additionally, hays contain a variety of fiber types and complex plant carbohydrate compounds that can only be fermented in the large intestine. The bacteria and yeasts in the large intestine work together to efficiently ferment. For example, some species will ferment starch, sugars, and fructans into lactate while others will use that lactate as their fuel, preventing acidosis that could harm the fiber fermenting organisms. The population of organisms in the large intestine will mirror the food that is presented to them but efficient adaptation takes time. Allow at least 5 to 7 days to make a complete change