The horse, as a prey animal, expresses pain in ways that are consistent with strong “flight” responses. In other words, horses don’t want to show they are weak or disabled for instinctual fear they will be selected by predators. (Never mind the worst carnivore they have to encounter on an average day is the barn cat.)

For those familiar with horse behavior, some signs are telling. Severely painful conditions elicit the most profound reactions and behavior in horses. For example, a colicky horse might display distress by kicking at his abdomen, biting his flanks, rolling or thrashing on the ground, or frantically trying to escape the “monster” in his belly. Heart and respiratory rates elevate, and his body might be soaked in sweat.

Milder conditions provoke less dramatic responses, with behavior usually correlating to a horse’s degree of pain. A horse with mild colic might seem apathetic to surrounding stimuli, while mild musculoskeletal pain might elicit restlessness, distraction, or performance below expectation. A stoic horse might express only subtle changes in mood, gait, or performance– these individuals are a challenge to identify. Others are more demonstrative in their discomfort, displaying visible lameness or positional changes to relieve a throbbing limb. Lasting chronic painful conditions take their toll; a horse becomes depressed and dull, with associated weight loss from lessened interest in food