Managing Stable Vices - Are they vices or a product of their environment?
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By Georgie White
We often see the word “vice” used in the equestrian world to describe an undesirable behavior completed by a horse; these are often repetitive behaviors completed either at certain times of the day, prior to or following a particular event or activity which causes the horse stress for whatever reason. When we look to the dictionary definition of a vice, the words “immoral,” “corrupt” and “wicked” are synonymous; but these are all words used to describe premeditated or deliberate acts of wrongdoing. When we consider that these are horses we are talking about, they simply do not have the cognitive ability to do this. As humans, we tend to over complicate and anthropomorphize animal behavior, likening it to our own and thus presuming horses complete these behaviors for far more complex reasons.
Recently the term vice has been replaced with a more correct term: “stereotypical behaviors” or “stereotypies,” which encompasses any behavior deemed to deviate from normal behavior and has resulted from the horse coping with a challenge or stress. On the surface, the behaviors appear apparently functionless, but when understood as a coping mechanism rather than a premeditated misdeed, we can begin to understand what that behavior serves the horse, if only temporarily.
What is stress?
Stress is the body’s response to a potentially threatening situation and is experienced by humans and animals alike and even serves as a function to keep the animal alive. Presence of a short-term stressor such as a predator serves to kick-start the fight or flight response, which is part of the acute stress response. Stress can be divided into two subtypes: acute and chronic, which are dealt with by the body very differently. They also result in several different physiological adaptations that are notable when discussing stereotypical behavior.
Acute stress refers to a short event or episode that causes a temporary increase in heart rate, respiratory rate, salivary cortisol levels, increased blood pressure and muscle tension. In relatively healthy animals, once the stressful event has passed, these body parameters will return to a base-line normal. These short episodes are not always necessarily bad and can help a horse learn and adapt to their environment. As horse handlers, we also know we can help a horse habituate to a common stressor by regularly introducing them to it and giving them a positive experience. Over time, their stress response will become less severe, and thus they will learn to cope with it reoccurring.
Chronic stress refers to emotional pressure suffered for a prolonged period of time, which an individual perceives to have little to no control of—the latter part being key in horses. Stereotypical behaviors will often occur during times where horses cannot control their environment. Stabled horses are most likely to display stereotypical behaviors because they are often in a situation when they cannot immediately change their environment or remove themselves from a particular stressor. Symptoms of chronic stress include weight loss, decreased appetite, negative demeanor or aggressive tendencies.
Horses suffering from chronic stress sometimes go unnoticed because the signs are more subtle; there is no pounding heart rate, sweating, increased breathing rate or more obvious cues that handlers may associate with a typically stressed horse. The other problem is that stereotypical behaviors can go ignored or become “just something they do.”
There is a common link between horses who display stereotypical behaviors and those diagnosed with gastric ulcers as both are closely related to chronic stress. There is debate over cause and effect, whether the horse performs these behaviors in an attempt to ease the discomfort of gastric ulcers or if those performing stereotypies are chronically stressed and at higher risk of developing gastric ulcers.
Typical stereotypical behaviors
There are several common stereotypical behaviors seen in domesticated horses, and they can be divided into two simple categories: oral and locomotor.
Oral stereotypies include crib biting, wind sucking and wood chewing; there is varied opinion suggesting these behaviors may provide temporary alleviation of stomach discomfort.
Oral stereotypies include crib biting, wind sucking and wood chewing; there is varied opinion suggesting these behaviors may provide temporary alleviation of stomach discomfort, but this is a question for cause and effect. Locomotor stereotypies include weaving, box/fence walking and door kicking. These behaviors expend a lot of energy, especially if the horse devotes a significant amount of time to this behavior and as a result, the horse can be prone to losing or maintaining condition.
There is research to suggest that if performed for long enough, stereotypical behaviors become a habit; and act as a reward to the horse, the release of endorphins occurs which reinforces repetition. Further to this, it can also be preempted by a horse who regularly experiences the same stressor at the same time of the day, each day and will therefore begin the behavior before the stressful event occurs.
Individual horses will vary in the degree of persistence and vigor to which the behavior is performed; and this largely depends on how much of the horse’s time is devoted to the behavior and how often the trigger event occurs in the horse’s routine. Some horses with stereotypies will appear to have a generally nervous demeanor, and others are relatively even-tempered and well-adjusted animals who otherwise do not appear to be suffering adversely from their environment. Some horse owners will notice a trigger or a marker that often sets off the behavior, in this case the stereotypy is easier to manage (e.g., ensuring that the horse is turned out first or fed first to prevent weaving or door kicking). When there appears to be no causative link, solving the stereotypy may become quite difficult especially if the horse has routinely done it for some time, as this becomes an ingrained habit.
A little about anatomy
The left hemisphere controls routine, internally directed or self-motivated behaviors in relatively low stress and familiar environments; examples would include foraging and grooming other horses. On the other hand, the right hemisphere is responsible for environmental-motivated behaviors, emotional arousal and unexpected or threatening stimuli; this refers to natural behaviors that have been redirected to other objects or pastimes when the previously innate option is not available. These may include crib biting, bed foraging and wind sucking.
The horse’s brain and associated physiology is quite different from the human; in part this can be attributed to the fact that horses are prey animals, and their innate fight or flight response is regularly triggered. …
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