The term cribbing is used to describe the behavior of a horse who rests his top teeth on a relatively stationary object and sucks air into his throat. About three percent of all horses crib, although in some populations of thoroughbred racing horses, this figure may be as high as 10 percent.
Cribbing is a stereotypy, a repetitive sequence of behaviors that appears to have no purpose. It occurs in all breeds of horses, regardless of temperament, and lasts about three to five seconds. A horse first presses his teeth on an object. Usually any object will do, including a feed bin, a bucket, the top of the stall door or a stall board, a fence or post, a tree trunk or limb, or even the horse’s own foreleg or a human conveniently standing nearby. The horse then contracts his muscles and arches his neck, pulling on the object while sucking air back into his throat and then releasing the air all at once. The release of air makes a distinctive belching or grunting sound. Wind-sucking is similar to cribbing and produces the same noise. The difference between wind-sucking and cribbing is that when wind-sucking, a horse doesn’t steady himself on a stationary object before drawing air into the back of his throat.
The following are some common features associated with cribbing and horses who crib:
- Front tooth wear
- High energy level, impatience and restlessness
- Difficulty in maintaining weight
- Thickened neck muscles
- Stomach ulcers and a history of colic
- Sport horse breeding
Cribbing is often associated with stress and frustration in horses. It can develop when horses are working in high-stress situations, such as focused training. It can also occur in horses who are subjected to tight management practices that involve confining them to stalls for long periods of time without breaks for foraging. Once a horse begins to crib—for whatever reason—he will persist with the behavior throughout his lifetime, particularly if he’s in his stall and excited in any way. Although many horse guardians see cribbing as an indication of poor care, sometimes it isn’t. Studies have shown that horses can develop cribbing behavior even when they live in a pasture with other horses.
Horsie See, Horsie Do?
Many horse guardians worry that their horses who don’t crib will learn cribbing from those who do. Some stable managers even refuse to accept cribbers for this reason. However, research and observation indicate that it probably isn’t a behavior learned from other horses. For instance, in one research stable where scientists were attempting to evaluate medicine to reduce cribbing and other stereotypies in horses, many horses who did not crib were exposed to others who did. Despite daily exposure to horses who were cribbing, not one of the horses who weren’t cribbing picked up the behavior. In fact, it’s rare to find a barn full of horses who crib. In stables with more than a couple of cribbers, the cause is often related to management practices that are the same for all horses.
How Serious Is Cribbing?
Most horse guardians will tell you that cribbing causes colic. Although it may cause one type of colic, it doesn’t seem to cause other types. However, cribbing is undesirable for several other reasons.
- Cribbing causes excessive wear of a horse’s teeth. In severe cases, it wears them down to the point that a horse can’t chew his feed properly.
- A horse may spend more time cribbing than eating. Since cribbers are often high-energy individuals who have difficulty keeping weight on, cribbing can cause a horse to chronically lose weight. This creates a difficult situation for the horse’s guardian, because adding high-concentrate feed to encourage weight gain can increase the cribbing.
- Cribbing damages the objects a horse cribs on. Although horses don’t actually chew when they crib—chewing is a different repetitive behavior—some crib up to 18 times per minute, and such highly abrasive activity wears down surfaces rapidly.
Why Do Horses Crib?
Cribbing doesn’t appear to serve any useful purpose. For some horses, however, it may help constrict the muscles around their stomach and help them deal with stomach pain. This idea is supported by the fact that cribbers colic more than other horses. It was once thought that colic was caused by the cribbing itself—a horse sucks air into his stomach, and this excess air causes colic, similar to how babies who swallow air experience tummy upset. But research shows that little or no air goes into a horse’s stomach when he cribs. So it’s now thought that cribbing might be a result of stomach upset. Cribbers as a group have more stomach ulcers than horses who don’t crib. However, the stable management practices, feed types and training regiments that can contribute to cribbing may also contribute to the formation of ulcers. It’s possible that cribbing and stomach upset simply have a common cause.
Although no one thing has been singled out as the reason horses crib, seven factors are associated with cribbing in general. Most of these factors are related to how a horse’s day is managed.
Being of particular breeding doesn’t automatically mean a horse will crib, but cribbing can run in families. A foal may have a genetic predisposition to crib, so if he’s exposed to stressful conditions, such as those listed below, he’s more likely to deal with his stress by cribbing.
Lack of Social Interaction with Other Horses
As a herd animal, your horse’s natural desire to be with other horses is very strong. Studies show that horses who have limited social contact with other horses, especially limited visual contact, engage in more compulsive behavior than horses who socialize regularly.
Lack of Grazing or Foraging Opportunities
Given the opportunity, pastured horses spend 8 to 12 hours a day grazing. Grazing is an important part of a horse’s welfare. Horses graze to satisfy nutritional and behavioral needs. Unfortunately, stabled horses can’t always be given continuous daily grazing time, either because of stable management or because it isn’t practical or safe. When deciding where or how to stable your horse, remember that the likelihood of your horse developing cribbing behavior is higher if he’s only given minimal grazing time and fed a single type of forage twice per day.
A High-Concentrate Diet
Feeding your horse a high-concentrate diet increases the risk that he’ll develop cribbing. People don’t always agree on exactly why this is the case. There are many reasons why high-concentrate feed may contribute to cribbing. First, it changes the pH balance of a horse’s stomach fluids, and that can cause stomach upset. In addition, ulcers are common in horses, and high-concentrate feeds can increase the pain caused by ulcers. Many experts believe that cribbing may be an attempt to reduce stomach pain, a hypothesis supported by the fact that cribbing often occurs within half an hour after feeding. High-concentrate feed can also increase a horse’s energy level, which can then increase his anxiety. Cribbing may reduce this anxiety through the release of endorphins, a natural opiate produced in the brain. (Please see Addiction, below, for more information about endorphins.)
Confinement and Boredom
Confinement and boredom have been found to contribute to the development of cribbing.
There is considerable evidence, at least in thoroughbreds, that weaning age and weaning methods have a big influence on the development of cribbing. Foals who were weaned young—particularly those who were also then fed a high-concentrate diet—often start to crib between one and one-and-a-half years of age. Some experts think that the feed and stomach pain may be the most important factors in the development of early cribbing behavior. Others believe that the age of weaning alone is to blame. It’s difficult to evaluate the relative influences of these factors because foals who are weaned early are almost always fed high-concentrate feeds.
Although addiction isn’t a cause of cribbing, it might contribute to the continuation of the behavior. Studies show that cribbing causes a release of endorphins, the brain’s natural opiate. The body generates them to help with pain reduction, but they also cause a general feeling of well-being. Just as a person can become addicted to drugs, a cribbing horse can become addicted to endorphins. This addiction may maintain cribbing behavior. Medicines that block endorphins reduce cribbing in the short term.
Ruling Out Injury or Medical Conditions as a Cause
Horses often exhibit unusual movements when they’re in pain or suffering from neurological disorders. If your horse has no history of compulsive behavior and suddenly begins to do things such as cribbing, head bobbing, self-biting, foot stomping or other behaviors that may indicate distress, please have a veterinarian rule out medical causes.
How to Treat Cribbing
The treatment of cribbing can be divided into two categories: preventing cribbing from developing and treating existing cribbing.
Prevention measures include providing your horse with 6 to 10 hours of grazing time with other horses, feeding him low-concentrate diets, providing him with daily, varied exercise and providing him with varied foraging types when feeding him hay in the stall.
Unfortunately, many horse guardians are unable to provide their horses with the optimal daily regimen that can reduce the risk of developing cribbing. For tips on how to help your horse cope under less-than-natural lifestyle conditions, please see Enriching Your Horse’s Life.
Treating Existing Cribbing
The bad news is that established cribbing is very difficult—if not impossible—to eliminate. In fact, there are no reported cases of successfully eliminating a horse’s cribbing behavior. Treatment for cribbing will vary with each horse, depending on the history of his cribbing behavior and his activities with his guardian. Many people use an anti-cribbing collar to reduce cribbing. The collar fits snuggly around a horse’s neck and often has a heart-shaped metal object at the point of the throat. The collar makes it difficult to suck air into the throat, and the metal point causes discomfort, which reduces cribbing behavior. However, we do not recommend anti-cribbing collars because they have been shown to increase stress in horses. Instead of using a collar, you can manage cribbing by providing your horse with alternatives to cribbing, such as increased and varied training opportunities, and increased grazing and foraging time. The following management practices can also reduce cribbing:
- Increase forage and turn-out time in a pasture. Frequent turn-out reduces cribbing, although some established cribbers will crib on fence boards and posts and on trees.
- Cut back on high-concentrate feed. If that isn’t possible, use a fat-based or oil-based diet, such as beet-based feed, rather than a carbohydrate-based diet, such as corn-based feed. High-fat diets also have been found to help horses perform longer without getting tired and to maintain better body weight than grain-based diets.
- If you must feed a carbohydrate-based diet, supplement it with antacids. Antacid treatment has been shown to reduce cribbing in horses who crib after eating concentrate feeds. Of course, if this treatment is successful, it may be an indication that your horse has stomach ulcers. If he does, they should be treated by a veterinarian.
- Bed your horse on straw. Straw forces a horse to pick his hay from the straw, and this is similar to what a horse does when he’s grazing. It’s important, though, that you make sure your horse doesn’t eat too much of the straw, because this has recently been found to lead to impaction of horses’ bowels.
- Feed concentrates from a foraging apparatus, such as an Equiball. These toys are appropriate only with the right type of bedding, such as straw. Do not use foraging toys if your horse could ingest sand or other fine particles.
- Decrease stall confinement, either by increasing turn-out time or increasing exercise and fun training activities like trail riding.
- Provide suitable cribbing surfaces. Many experts feel that cribbing may benefit horses by allowing them to reduce pain or deal with frustration. For this reason, most experts feel that instead of preventing the behavior through the use of straps or surgery, it’s better to let a horse crib on something that he can’t wreck and that won’t hurt him. Suitable cribbing surfaces can be created out of heavy rubber, such as old car tires.
- Increase contact with other horses. If it isn’t possible to turn your horse out with other horses, it may help to place him in a stall next to another horse who he can see.
For additional information about how to reduce behaviors like cribbing, please see our article on Compulsive Behavior in Horses.
As mentioned above, it‘s often not possible to eliminate cribbing by correcting the problems that contributed to its development. For this reason, care should be taken to provide horses with highly enriched environments to prevent behavior problems before they develop. To learn more about ways to provide environmental enrichment for your horse, please see our article on Enriching Your Horse’s Life.