There are moments spent with our horses that are often taken for granted: The welcoming whicker as you approach with dinner, the snuffling in the feeder for tasty bits and pieces, the melodic sound of chewing as your horse enjoys every morsel, and the sweet smell of hay as it is crushed between your horse’s teeth. When these ritual sounds and senses of the day go missing, there is a sense of dread.

Your horse isn’t interested in coming in for dinner. Out in the paddock, he is occasionally pawing the ground, half-heartedly. With a sigh, he plops to the ground, lying quietly. After a few minutes, that doesn’t seem to suit him either. He rises, shakes his neck and head as if to throw off a cloak of discomfort, then stands despondently.

Although this presentation might be typical of a horse that simply isn’t feeling well, it is also quite typical of a horse with intestinal discomfort from impaction colic.

What is Impaction Colic?

Impaction colic is caused by a blockage that forms due to feed material obstruction in the large colon. Nat White, DVM, MS, Dipl. ACVS, and Marco Lopes, DVM, MS, professor at the veterinary school in Brazil, have pursued colic research at the Marion duPont Scott Equine Medical Center in Virginia with support of the Grayson-Jockey Club Research Foundation. White, director of the Equine Medical Center, says, "Large colon impactions make up as much as 8-10% of all colic, but the cause in a large majority of the cases is not known. Nearly 30% of all equine colic cases at referral hospitals are attributable to an impaction."

As food traverses the digestive tract, i