Wild horses are communal by nature. In a herd environment, wild horses are known to act out long-standing social rituals, which stem from the need to determine territorial leadership and breeding rights. These interactions characteristically maintain order within the group as they establish close bonds. And, since horses are also habitual grazers, constantly on the move, they are also able to satisfy their exercise needs, and as a side benefit, release what would otherwise become pent up energy.
On the other hand, domesticated horses are subjected to vastly different environments, resulting in far different patterns of behavior. They often lead solitary lives in confined stalls with a prescribed exercise regimen (or not) and pre-determined feeding schedules. Often their rations are grain-based, rather than forage-based. Consequently, with the repression of vital aspects of their core makeup, it's not unusual for some horses to exhibit aberrant behaviors known as stereotypies, which are commonly referred to as ?stall or stable vices.? Welfare issue may also be associated with these behaviors.
Stable vices stem from a series of normal, repetitive motor activities, i.e. oral, locomotor, grooming, etc., that escalate to an unhealthy repetitive level and serve no useful purpose, and in worst case scenarios can be harmful to the horse. The most common stable vices include cribbing, weaving, circling, head bobbing, and pawing. These stable vices typically occur when horses are relegated to restrictive environments without the benefit of social interaction. Without resolving the underlying causative factors in the horse's environment, some welfare scientists believe punishment or physical prevention of stable vices is generally detrimental to the horse's well being and should be avoided.
One theory related to the onset of stable vices is that when a naturally-occurring behavior is prevented, it triggers an acute awareness of that behavior, which quickly escalates as the horse repeatedly attempts to find resolution. In a heightened state of anxiety, the horse becomes fixated with the process or ?stuck in motion? unable to stop, a pre-cursor to a chronic addiction.
Another theory points to two distinct stages of a behavior--appetitive (the initiation) and consummatory (the conclusion) that when reached, will reduce the initial drive. For example, the courtship ritual, which is an appetitive behavior, is terminated by mating, the consummatory behavior. But, when interrupted before the second stage is reached and thereby forestalling a satisfactory conclusion, the horse will return to the first stage with the expectation of finally succeeding. So, as with the above theory, if this behavior is continually thwarted, it could be an invitation for the horse to play out stage one again and again to the same chronic end.
The good news is that not all horses react to the same circumstances by displaying neurotic behaviors--it's an individual thing, dependant on a combination of genetics and environmental factors. Despite the anecdotal belief that stall vices can spread throughout a barn like wild fire, horses cannot learn these behaviors from watching each other. A horse's ability to survive in the wild requires it to maintain a basically self-centered view of life. In their development, unlike humans, horses do not learn to recognize other points of view, a prerequisite to learning a process by watching another individual.
Stable vices are thought to be coping mechanisms used to dispel anxiety. Trying to prevent them by using electric shock, drugs, surgery, etc., without taking into consideration and addressing the primary stressors, such as confinement, isolation, lack of exercise, etc., will not do much to quell the horse's angst and ultimately may be considered a cruelty. Nevertheless, if one is stabling a horse afflicted with a stable vice, it can become an annoying and frustrating management issue and can result in health consequences for the horse. It is much better to prevent the occurrence of stable vices than to have to deal with the full-blown vices. Following are the most common stable vices.
Seen when a horse grips an anchored object with his teeth, i.e., a rail, feeder, ledge that he'll then pull on to arch his neck, the position that best enables him to swallow air into his esophagus, his ultimate goal, which is often accompanied by an unpleasant grunting or burping noise. Thought to be an obsessive-compulsive disorder (OCD), it may be compounded by endorphins that are released with each intake of air to produce a ?high? that repeatedly rewards the behavior.
The theory that a chronic cribber will eventually colic from swallowing too much air has not been proven, especially as recent studies suggest the amount of air that actually reaches the stomach is negligible. But, it is the act of continually biting down, prematurely impairing the incisors? (front teeth) ability to grasp feed (essential to the digestion process), that may account for occurrence of colic symptoms. The sad truth is that there is no known cure for cribbing and, unfortunately, once established it is an almost impossible habit to break.
Typically seen in horses that are especially ?high strung? or nervous, weaving is considered to be a self-stimulating action. It is recognized by the rhythmic, lateral swaying motion that a horse exhibits as he shifts from one forefoot to the other with his head and neck, sometimes with hindquarters swinging in tandem. On top of which, some horses will frequently weave in front of the stall bars, which is thought to provide a kind of visual stimulation. Although it is a source of contention, it is argued that weaving can lead to weight loss, poor performance, uneven hoof wear, and abnormal stress on ligaments and tendons resulting in lameness.
Likewise, weaving, circling and stall walking are seen as obsessive-compulsive behaviors. Demonstrated by turning or walking instead of swaying, the horse will often leave a worn down trail in his wake. And like weaving, it is thought that these vices can cause weight loss and lameness in addition to damaging the stall floor.
Other stable vices such as wall kicking, biting, pawing and digging, and stabled horses that destroy buckets, mangers and blankets or routinely defecate in their feed or water buckets can easily become management challenges. If the underlying problems are not addressed there isn?t much hope of curbing these vices.
In the majority of cases, group pasturing in large paddocks where there is adequate grazing is deemed to be the ideal situation and can make a noticeable difference in horses exhibiting stable vices. But, as with all habits, they?re hard to break. In time the habits should moderate.
However, in situations where horses must be stabled, provide an environment where there is visual and physical interaction to reduce the potential for anxiety. The horse can also be kept occupied by providing sufficient exercise and feeding adequate forage, not only to meet its nutritional requirement but also to satisfy the horse's need to graze. The amount of forage fed at each feeding may be reduced while increasing the number of feedings.
Other management strategies can be initiated that may help keep horses occupied if turn-out time is limited or not possible. For instance, there are a number of equine toys available that are specifically designed to keep horses occupied. Balls or plastic milk cartons hung in stalls have proven useful in alleviating boredom. Placing a companion animal in an adjoining stall is another method to help distract the horse. Reducing the amount of high-starch feed will help limit the amount
of short-term energy the horse receives, which may have an impact on development of stable vices.
It is in the horse's and owner?s best interest that the horse's nutritional, physical and psychological needs are met. This will reduce stress, enabling a greater degree of comfort. The result will be a more enjoyable horse for the owner to handle. Stable vices are repetitive behaviors arising from a combination of environmental and genetic risk factors in a given individual at a given time. Prevention should be targeted at reducing risk factors. Access to herd mates, pasture, turn out, high-forage rations and limited grain are all recommended, especially when working with horses that possess the genetic predisposition for hyperactivity or during critical stress periods such as weaning. Even if access to unlimited pasture space is not available and extended turn out time cannot be arranged, by understanding the inherent ?herd mentality? in domestic horses, and by incorporating the practices that most closely resemble their natural behaviors, stable vices may be deterred. This is by far the best-case scenario.
For more information about the feeding and care of horses, visit ADM Alliance Nutrition?s online equine library. For free feeding suggestions for your horses, call the Equine Nutrition HELPLINE at 800-680-8254.
Reprinted with permission from ADM Alliance Nutrition, Inc., 1000 N 30th St, PO Box C1, Quincy, Illinois, USA 62305-3115; 800-680-8254; www.grostrong.com.Judith A. Reynolds, Ph.D., P.A.S., Dipl. A.C.A.N., is the Equine Nutritionist and Equine Product and Technical Manager for ADM Alliance Nutrition, Inc.