What does a horse have to worry about? Not too much, you’d imagine, as he stands rugged up and warm in his stable awaiting his evening meal. But while he may not be fretting about paying the bills or his next career move, your stabled horse could well be feeling strain of a different sort. Unable to exercise his freedom or indulge his natural urges, he might seek to relieve the stress caused by confinement or isolation by developing his own coping mechanisms.
Some horses become more anxious in the stable than others. An inability to cope with restricted movement, food or social contact can lead to undesirable behaviours such as crib-biting, weaving, windsucking and box walking – with these stereotypies (traditionally called ‘vices’) often regarded as a fault or misbehaviour on the part of the horse, rather than a result of the unnatural environment he’s kept in.
In the past, most treatments have used physical intervention to prevent the horse carrying out the activity, such as foul-tasting pastes to deter the crib-biter from latching onto parts of his stable, and tight-fitting neck collars that make it harder for the wind-sucker to gulp down air. However, instead of merely addressing their symptoms, modern thinking seeks to better understand the cause of these behaviours in an attempt to create more effective methods of relief.
Here, equine behaviour expert Dr Debbie Marsden helps us understand stereotypies.
A crib-biter will grasp a fixed object with his incisor teeth and bite down onto it.
Crib-biting is sometimes accompanied by wind-sucking – where the horse arches his neck and gulps down air, usually with a loud grunt. Chronic crib-biting can cause uneven wear of the teeth, but occasionally a horse will wind-suck without crib-biting.
The stationary horse moves his weight from side to side, usually with a corresponding head and neck motion and sometimes lifting his forefeet as he sways. Weaving is performed at times of excitement such as feed times, or continuously in the stable or over the stable door. Some horses, particularly ex-racers, who’ve had weave bars previously may have developed an ‘on the spot’ weave (less side to side and more up and down).
A box-walker will make repeated circuits of his stable or pace back and forth behind the door. Usually a result of anxiety due to confinement and separation from others in the horse’s ‘herd’, box-walking is sometimes triggered by an unusual commotion in the yard or a move to an unfamiliar stable.
Less common stereotypies
These include circling, head twisting, tongue flicking or curling, teeth grinding and self-mutilation. While non-stereotypic or learned behavior includes wood chewing, relentless gnawing of wooden surfaces and aggressive behaviour. This can be directed at people or other horses and may take the form of kicking, biting or other threatening head movements such as teeth snapping. Other habits that may indicate unsuitable management include pawing the floor, bed eating, door kicking and head nodding.
Spotting a stereotypy
Most horses have their quirks and funny habits, but how do we distinguish between a true stereotypy (or vice) and the kind of learned behaviour problems so commonly seen on the yard? According to Debbie, one of the chief identifying factors is whether or not there is an apparent goal for the horse’s actions.
“Stereotypic behaviour is traditionally defined by a lack of obvious motivation or function,” she explains. “So while kicking the stable door at feed-time in an attempt to hurry up the arrival of a meal would indicate learned behaviour, relentless box-walking would be classed as a stereotypy – even though the calming effect a stressed horse might experience by pacing around the stable could be considered some sort of goal.”
Stereotypic behaviour can also be identified by its strictly repetitive nature, she explains, and sudden arousal such as a yell or the crack of a whip can worsen the problem. Even threats or punishment make little difference. “As the goal of the behaviour is its actual performance, subsequent pain or adverse consequences don’t affect it,” says Debbie, who adds that horses performing a stereotypy experience an increase in ‘feel good’ beta-endorphins. “This explains why horses with stereotypic self-mutilation continue to bite and lick at an open wound.”
While many stereotypies may look bizarre to us, Debbie points out all are based on elements of natural behaviour – albeit without the usual goal.
“Examples are teeth grinding without food to chew on, and tongue-flicking in the absence of grasses to be selected,” she says.
The main causes
Studies suggest that as many as one in 10 horses exhibits some kind of stereotypic behaviour – sometimes more than one type – and that the problem occurs in many different breeds and in all ages. So why do some develop stereotypies? According to Debbie, it’s a combination of a horse’s genetics, his life history and the environment he lives in.
“An estimated 40% of the equine population are genetically predisposed to stereotypy,” she explains. “Even if he inherits a predisposition to do so, however, a horse will not necessarily develop a stereotypy unless he is placed under certain management conditions. Conversely, any horse could develop one if sufficiently stimulated.”
Factors that trigger stereotypic performance, explains Debbie, include frustration, excitement, stress or pain. These could stem from the horse’s early life, perhaps around weaning-time, or by aspects of day-to-day management – especially the practice of stabling a horse for long periods so he cannot interact with company or otherwise occupy himself with activities such as grazing.
Additional triggers include feeding time, seeing stablemates leaving the yard, being moved to a new box or meeting new horses. Less frequent events such as travelling, moving yards, or alterations in work, fitness or diet are also thought to stimulate stereotypies in susceptible horses.
New behaviour patterns could indicate underlying health problems, so Debbie advises consulting your vet if you spot the onset of a stereotypy. But, in the absence of any obvious direct physical causes, it’s now thought that a horse is less likely to develop coping mechanisms in the form of stereotypies if sufficient consideration is given to his natural requirements.
“It’s now widely recognised that ‘stable vices’ are not misbehaviour but a sign or inappropriate husbandry,” says Debbie, who recommends reducing anxiety through specific and permanent changes in management. “It’s proven that the time spent performing abnormal behaviour decreases with time spent feeding, so ideally the horse should be feeding for between 12 and 18 hours a day.”
If a horse is stabled, Debbie advises providing forage in small-holed nets and feeding a high-fibre, low-calorie diet.
“Strict routine can actually encourage frustration instead of relieving it, especially around feed time, says Debbie. “Ideally, put the feed in the stable before the horse is brought in, and try sprinkling concentrates among the forage ration to avoid the arousal caused by a highly palatable diet and the associated burst of beta endorphins.”
Turning a horse out might seem the obvious solution to a lack of social contact, but Debbie advises arranging company carefully to reduce excitement and prevent stress caused by bullying.
“Select small groups of three to five horses of mixed age and gender, and allow to them to form long-term relationships,” she suggests. “Loose yarding or partitions that allow maximum possible physical contact and a choice of neighbour are a good idea for the stabled horse, while a safety mirror may relieve feelings of isolation if the horse must remain alone.
“It will take at least two to three weeks for any noticeable improvement as a result of a management change – and three to six months before the behaviour is eliminated,” says Debbie. “But the behaviour will return if the horse is placed in that same stressful environment.”