Horses naturally want to nibble and graze. In the wild, they keep themselves occupied by wandering and grazing. The domesticated horse, however, may be stabled most of the time, eating and drinking only when he's fed or watered and exercising only when taken out of the stable.
In such situations, the horse's natural grazing instincts are somewhat satisfied by substitute behaviors, such as chewing wood in the stall.
Other less common behaviors that are thought to be linked to domestication are "cribbing" or "crib-biting" and "wind sucking". The symptoms of these are easily recognized and quite shocking for the uninitiated. A cribbing horse will anchor his upper front teeth onto the stall door, partition or post. Then he tenses up his neck and facial muscles, retracts his larynx (voice box), and gulps down air. A wind sucker flexes his neck, gulps air and emits a grunting sound. Unlike cribbers, horses that wind suck don't need to grasp an object to perform this act.
Why Does Your Horse Do This?
"Cribbing is a horse's way of managing his innate desire to nibble, after he's already eaten his daily allotment of food," says Scott Pierce, DVM, an equine veterinarian in Lexington, Kentucky. He says putting a horse on pellets, hay cubes or mostly grain can exacerbate the situation. With this feeding method, the horse will be able to consume his food in a short amount of time, thereby not satisfying his need to nibble.
Wind sucking is thought to be primarily a result of boredom, which can also motivate a horse to crib. "A horse with nothing to do may learn to amuse himself by wind sucking or gnawing the stall or any other wood that is accessible," says Kathryn Houpt, VMD, PhD and director of the Animal Behavior Clinic at Cornell University. Studies show that less exercise exacerbates habits such as wood chewing, but a direct link between exercise, cribbing and wind sucking has not been established.
Some recent evidence suggests that this behavior may be inherited. There is also the theory that these behaviors represent an obsessive-compulsive-disorder (OCD) and is triggered and/or exacerbated by aspects of domestication. This theory has led to attempts to treat the problem with anti-OCD medications, but there is no satisfying data as this time to support or refute their use.
Once a horse starts to crib or wind suck, he can become addicted to the behavior. Some behaviorists believe that when a horse cribs or wind sucks, narcotic-like substances, called endogenous opioids, are released in the horse's brain. Chief among these are endorphins and enkephalins, morphine-like proteins, which suppress pain and activate the brain's "pleasure center."
"This endorphin release is almost like getting a narcotic high and so the horse keeps going back for another dose," Houpt says. "While factors such as diet or boredom can get a horse started, the behavior may persist when the horse experiences the endorphin release."
Curb Your Horse's Bad Behaviors
Cribbing and wind sucking are bad habits and should be discouraged. Cribbing can result in excessive wear of the incisor teeth. Both wind sucking and cribbing can result in over development or enlargement of the neck muscles and poor performance. Additionally, a cribbing horse can do considerable damage to a barn or stall. You should take steps to curtail the problem the first time you see any inclination in your horse towards cribbing or wind sucking. Here are some suggestions:
Make cribbing less enjoyable
Paint fences, gates and partitions with creosote or an anti-crib liquid (there are several commercial mixes on the market) to make them less appetizing. Or, mix up your own concoction of cayenne pepper and petroleum jelly. It's probably best to check with your vet about potential side effects of these products before applying any of these home remedies.
Remove crib-friendly objects from the stall
For example, don't leave any racks or wooden feeders in the stall that your horse could get a hold of. Keep the top of the gate closed and cover their favorite gnawing edges of the stall with metal trim (but be sure the sharp edges are turned under).
Heighten your horse's world
Raise your horse's water bucket and feed tub up to the level of his chest and eliminate all edges up to that height. In order to crib, a horse needs to be able to arch his neck. He won't be able to do this if his chin is above his chest level.
Keep your horse occupied
If the motivator for these bad behaviors is boredom, turn him out more frequently or for longer periods to allow him additional opportunities for exercise. You may also want to provide him with stall toys - to help him occupy his time when he must stay in his stall. Some people even try to have companion animals for their horse, whether it is another horse or a different type of animal altogether, such as a goat.
Consider using a collar
A cribbing or wind sucking collar is a broad strap that is placed around your horse's neck to deter him from flexing his neck muscles whenever he tries to suck in air. The collar essentially disables those muscles of the neck that are essential to this movement and in some horses probably causes pain with such movement. "The collar should be adjusted so that it's snug enough to be effective, but loose enough so that the horse is comfortable when he eats or otherwise behaves normally," Pierce says.
If doubtful about what course of action to take, talk with your trainer or equine veterinarian. Don't just hope this vice will go away by itself. Once your horse's vices are under control, both your horse and your property will be much better off.
If all of the above fail, surgery may be your last resort. The success of surgery is variable with generally a 50 percent improvement rate. Your veterinarian can give you more information regarding this option.