Carissa Wickens, University of Florida, and Camie Heleski, University of Kentucky
Stereotypic behaviors are defined as repetitive, relatively unvarying patterns of behavior with no obvious goal or function. A horse that displays stereotypic behavior tends to perform the behavior in nearly the exact same way every time, and many horses also perform the behavior in a preferred location, e.g., in a specific area of the stall or paddock. This article will share what we have learned about stereotypic behaviors through science, and how this information can be applied to better manage and thus improve the welfare of horses with stereotypic behavior.
Stereotypic behaviors (STBs) are often referred to as “stable vices”. However, we are moving away from using this terminology to describe stereotypies, as research studies aimed at further investigating STBs in horses are demonstrating that these behaviors are not simply the result of boredom. These behaviors are not an attempt by the horse to be a nuisance to their owner and should not be considered to be the fault of the horse. Although the exact, underlying cause(s) of STBs remain unknown, we have gained a better understanding of how, or rather why, stereotypic behaviors develop in horses. The development and continued performance of stereotypic behaviors appear to have a physiological or psychological basis.
Most survey studies conducted to date (Wickens and Heleski, 2010), show 4-5% of the average horse population engage in an oral STB, such as cribbing, crib-biting, or wind sucking. The cribbing horse (cribber) places its front teeth on an object, such as a fence board, pulls back while sucking air inward, and then emits a grunting noise. Some evidence suggests that these behaviors are the result of “feel good” neurotransmitters in the horse’s brain, which is probably why the behavior seems so addictive, and so challenging to stop once it becomes established.
There are two common locomotor STBs observed in horses. One is called weaving, where horses shift their weight back and forth on their front legs (a repetitive, side to side swaying motion). This is often performed when standing at the front of the stall or next to a paddock gate. It often coincides with anticipation of something, e.g., awaiting morning turn out, or while waiting to receive feed. The second is called box walking or stall walking, and it literally means to walk part or all of the horse’s box stall (or paddock) perimeter.
Risk Factors for Developing STBs
Though direct cause and effect research on this topic remains limited, multiple studies involving thousands of horses have consistently found the following factors to be associated with increased likelihood of engaging in a STB (Wickens and Heleski, 2010):
- Insufficient or limited turnout time
- Insufficient or limited opportunities to socialize with other horses
- Insufficient or limited grazing and foraging opportunities – this factor often goes together with high concentrate diets, which have also been implicated
- Stressful weaning, particularly an abrupt method with individual housing
Additionally, there is evidence that young stock with gastric ulcers are more likely to be crib-biters. In one study, supplementing young horse’s feed with an antacid improved the condition of the stomach, and tended to reduce the amount of time horses spent cribbing. Some differences in brain physiology responsible for goal directed and reward seeking behavior have also been demonstrated between horses with STB and horses who do not show these behaviors.
Some factors are more ambiguous, such as stallions being more prone to engage in STBs, “stressful” riding disciplines being more prone to result in STBs, certain genetic lines being more likely to crib or to weave, and horses recovering from illness or injury being more likely to start a STB. However, in most of these cases, careful assessment will also note that turnout time, social interaction and foraging opportunities are also likely limited.
Commonly Held Beliefs
Contrary to popular opinion in the industry, there is no scientific proof that horses learn STBs from one another. Anecdotally, when stereotypic horses are turned out to pasture with non-stereotypic horses (those horses who do not display a STB), the non-stereotypic horses do not pick up the STBs. There is however less consistent evidence when it comes to housing non-stereotypic horses next to or across from stereotypic horses in environments involving the risk factors mentioned above.
Should I try to stop it? And if so, how?
If you own or manage a horse with a STB, the recommendation is to learn as much as possible about that behavior. Stereotypic behaviors are recognized as both a welfare and a management concern, and many owners attempt to physically prevent the behavior. Attempts to physically prevent STBs can result in reduced welfare for the horse and additional strain on the owner’s pocketbook. Therefore, strategies aimed at addressing the behavior should include consideration of potential causal factors and implementation of management practices known to help reduce the behavior (e.g., increased opportunities to socialize with other horses and to graze and consume forage).
Some horses will engage in their stereotypic behavior so much that it reduces their time spent on consuming adequate feedstuffs to maintain a desired body condition. With respect to cribbing, some owners have had success with various cribbing collars and/or anti-cribbing muzzles. Care should be taken when turning horses out as many of the collars do not have breakaway mechanisms in the event of entanglement. Also, even a well-fitted collar or muzzle will often create rub lesions on the horse’s head potentially resulting in sensitivity around the poll. Collars must be properly fitted and kept clean. Use of fleece covers can help make the collar more comfortable for the horse.
Always remember that somewhere along the way, the horse developed this STB because it was likely trying to “cope” with a suboptimal husbandry situation. If we view it as a coping mechanism, how certain are we that we should take away the horse’s ability to cope? Multiple studies have shown, when presented with a stressor, the horses who handled it least well were crib-biters who were prevented from cribbing; non-cribbers did fine, and cribbers allowed to crib were fine, but cribbers who were thwarted were more stressed.
With respect to the locomotor stereotypies, some owners have had success in reducing their horse’s weaving or box-walking by increasing the visual horizons, e.g., placing the horse in a stall with a window to the outdoors or with an acrylic/shatter-proof mirror, adding an anti-weave stall front that allows the horse to have its head and neck out in the aisle, or simply providing the horse with increased turnout time. Based on the authors’ experience and anecdotal reports from owners it appears much easier to reduce the time a horse spends engaged in a locomotor STB than an oral STB.
Just because your horse performs a stereotypic behavior, such as cribbing or weaving, does not mean its current state of welfare is suboptimal, but more likely, that at some point in the horse’s history, the horse was trying to cope with stressors outside the behavioral demands of the horse’s nature.
Managing stereotypic behaviors can be challenging. The best management strategy continues to be prevention by trying to optimize turn out time, social interaction, and grazing and foraging opportunities. Minimizing stress during the weaning process is important, and working hard to enhance natural behaviors when horses are on stall rest for injuries or illness can help reduce the chance that your horse will develop a STB.
C.L. Wickens and C.R. Heleski. 2010. Crib-biting behavior in horses: A review. Applied Animal Behaviour Science. 128: 1-9.
Is it coping or is it a vice? A review of cribbing, weaving, and other stereotypic behaviors in horses. My Horse University, January 2013 Webcast. Presenter: Dr. Carissa Wickens.
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