Cribbing or crib biting is the most common stereotypical behavior in the horse. It involves biting down on a solid object like a bar or stall door. It may or may note be accompanied by wind-sucking. Wind sucking involves opening the mouth, resting the top nipping teeth or biting down on a hard surface, contracting the muscles of the throat, flexing the muscles of the neck and sucking air into the first part of the esophagus. This is usually accompanied by a grunting or groaning sound. Some horses even learn to wind suck without the grasping behavior and so can perform the behavior without a surface to grasp.

A stereotypy or stereotypical behavior is defined as a repeated movement or behavior with no obvious function for the animal, and likely either caused by frustration, stress or brain dysfunction. There is confusion over the term stable vice, which implies that the horse is “acting badly”. Horses with stereotypical behaviors are acting out of frustration stemming from a deficiency in their environment. Stereotypical behavior is therefore a response to the conditions in which horses must live. Wild animals confined in zoos display similar behavior commonly. Examples commonly seen in these animals include constant pacing in an enclosure, and even self-mutilation. Lack of exercise, normal socialization and unnatural feeding practices probably all contribute to the development of stereotypies in both horses and zoo animals. Stereotypical behaviors are thus rarely observed in animals in their natural environments. Stereotypies are found more commonly in stabled and performance horses than in other groups of horses. Pacing and weaving are other examples of equine stereotypies. Less well-known behaviors that are probably stereotypical in nature include tongue lolling, excessive drinking, and odd leg gestures like crossing the limbs repeatedly.

Why do horses crib? Is there some value in cribbing that horses realize? There is some speculation that there is a relationship between the conditions that cause gastric ulcers- high grain diets- and the development of cribbing and wind sucking. We know that cribbing tend to be more common right after finishing a meal. There is some thought that this may be a response to abdominal discomfort from acid production in the stomach associated with consumption of high grain diets. Wind sucking has been postulated to provide some relief for that. Historically there has also been a thought that certain pleasure producing neurotransmitters may be released by these behaviors. Horses with brain disease rarely may also engage in certain stereotypies. There is little proof that horses mimic the behavior, and there is little proof for a genetic cause for the behaviors. The fact that family members all seem to do it probably more relates to their similar management than their similar genes.

Treatment for Cribbing and Wind Sucking
Changes in horse management to more closely mimic the normal state are the most effective strategies for control of these behaviors. As mentioned before, the real opportunity is in prevention of these behaviors, not treatment. Once the behaviors start, they typically are very difficult to eliminate.
That said., many devices and strategies have been advocated in treatment, and like so many other aspects of the horse industry, many claim miraculous results without any proof of real effectiveness. Cribbing collars are a popular treatment but do not always work. In my experience, most horses require ongoing tightening and maintenance of the collar. I have seen several horses injured by misapplied cribbing collars. If the collar is ever removed, the problem recurs with even more intensity. The application of shock collars has been advocated but effectiveness depends upon consistency and timing. There is also great opportunity for misuse or abuse with these devices. Drugs similar to those used in treating human drug addicts have been tried in horses with some success, but are in most cases impractical. There are several surgical procedures which have been advocated to treat cribbing. None are universally accepted, although they may help in individual cases. There is some anecdotal information suggesting that acupuncture may be helpful in treatment of established cribbers but to my knowledge this is anecdotal only.