Colic in horses is really a general term referring to abdominal pain. Colic can be caused by a horse overeating, a horse constantly swallowing air "wind sucking", a sudden change in diet, consumption of moldy feed, turnout on the wet pastures of early spring, a heavy meal before work, feeding or watering before proper cooling after work. Contrary to popular belief, there are many different types of colic, but they don't all arise from a torsion, or volvulus of the intestines.
I had a horse for many years, and only had to deal with 2 incidents of mild colic. Thank God! It's hard to imagine, but horses really are more fragile than you would think. It is so frightening to see a horse with a bad case of colic, but if caught early, it usually works out OK.
How did we get on this topic anyway? LOL!