Cribbing is a compulsive behavior, which horses sometimes develop as a result of boredom, typically resulting from being left in a box much of the day with nothing to do. It consists of the horse firmly biting an object, arching its neck while pulling on the object, and sucking in air. It is believed that this triggers the release of chemicals (endorphins) in the brain, giving a pleasurable sensation. Cribbing is also known as ‘wind sucking’ or ‘crib biting’.
Cribbing is sometimes confused with wood chewing but the two are different problems. A wood chewer simply nibbles on the wood, which is a habit that is easily treatable. A cribber pulls on wood (or other objects) while sucking air in order to release brain chemicals, which effectively makes it a drug addiction, and consequently much more difficult to cure.
Over time, cribbing will wear down and damage the horse’s teeth. The pulling motion results in an abnormal muscle development in the neck, making it thicker. A number of other illnesses, such as colic, are associated with cribbing but the relationship of these illnesses is unknown (e.g. does the colic pain promote the habit, or does the cribbing air sucking cause the colic, or are both colic and cribbing simply more likely in horses which lack pasture time).
Fortunately, it is possible to treat cribbing. Since cribbing is mainly due to boredom and lack of mental stimulation, one needs to provide the horse with interest and activity. Giving the horse as much pasture time as possible is very successful in reducing the amount of cribbing. Feeding should also be more interesting, with pasture feeding (eating grass) the optimum solution. If this is not possible, it should be moved to foods such as hay which have long chewing times rather than grain or muesli (which have short eating times and thus little stimulation). Many small feeds per day are better than one or two large feeds. Anything else which provides variety and stimulation, such as exercise and grooming, is also beneficial.
Unfortunately, once the habit of cribbing has been established, removing the cause will only reduce the frequency but not completely remove the cause. One also needs to stop the behavior as well. This can be very difficult as the horse can crib not only on wood, but on any item which in can hold tightly with its teeth and pull on. There are a variety of techniques to address this but no one technique works with all horses, so you may need to try different techniques until you find one that works with your horse.
One of the most common approaches is a ‘cribbing strap’, also known as a ‘cribbing collar’, which is a strap that fits around the neck with a mental plate on the underside to make it uncomfortable for the horse to swell its neck to suck air. Another device is the use of a muzzle, which allows the horse to eat but prevents it from grasping items with its teeth. One can also put a live (under current) fencing wire along fence rails to prevent the horse from grabbing the rails, or paint the rails with an unpleasant tasting paint (a number of veterinary approved products are available). In some cases, certain medications (in particular, anti depressants) are helpful. Finally, if all else fails, there is a surgical solution.
One should do both activities, remove the cause of the behavior by providing more mental stimulation for the horse and also use one or more of the above techniques to discourage the behavior. Addressing the cause but not the behavior is normally only partly successful. Alternatively, stopping the behavior (e.g. with a cribbing strap) without fixing the root cause of intense boredom may simply result in the horse developing alternative behavioral problems.