Equine Stereotypy Survey Findings
In 2004 Sue Allen distributed a questionnaire to horse owners to consider Equine Stereotypy. This was a study conducted towards Sue's Masters Degree in Animal Behaviour, to investigate stereotypic behaviours of horses. Sue has kindly granted permission for the findings of her study to be displayed here on the Voices for Horses website, in an effort to bring them to a wider audience, and because (to quote Sue herself) "the more people who understand these behaviours, the more likely affected horses will not suffer further reduced welfare by inappropriate treatments"
Introduction
"The reason I chose to research stereotypic behaviours of domestic horses is because performance of these behaviours reflects reduced welfare in the horse's life either in the past or present. Over one third of all domestic horses display one or more of these behaviours and this equates to many thousands of horses who live among us. It is because these behaviours are so common and seemingly difficult to treat that they are largely considered to be vices/oddities of the horse in question. However, if a polar bear were to be repeatedly pacing/ swaying or biting their bars in a zoo enclosure we would be very concerned and expect immediate action to be taken on the bear's behalf.
Much research is being undertaken by the worldwide scientific community regarding causal factors and treatment options for equine stereotypic behaviours. This study was very small in scientific terms and therefore limited conclusive results were to be expected. The majority of large studies have been on racehorses and high level competition horses and therefore, I just wanted to see whether similar trends in the data would be found when studying a varied range of horse breeds, usage, heights and weights.
Below, I briefly detail the main findings of the survey followed by brief information on current scientific thinking regarding the main causes and appropriate treatment options for each of the stereotypic behaviours under question.
Main findings of the survey
115 owners returned the surveys with details of 192 horses. The horses ranged from between 2 yrs and 19+yrs and from 8hh to 18.3hh.
The majority of owners spent less than 2 hrs with their horse per day but whether they spent a short or long time with the horse seemed to make no difference to whether it performed a stereotypic behaviour.
With regards to the four stereotypic behaviours of weaving, box-walking, crib-biting/ wind-sucking and wood-chewing, of all horses surveyed;
34.4% Performed one or more of these behaviours
13.5% Weaved
7.8% Box-walked
6.3% Cribbed or Wind-sucked
14.6% Wood-chewed
Horses that performed one or more of these behaviours spent significantly more hours within the stable than those who did not.
Weaving horses were significantly less able to see or touch other horses whilst within their stable compared to non-weaving horses.
Weaving was more likely to be displayed by horses of lightweight build and its prevalence increases with age.
The vast majority of all owners (whether they had a horse with a stereotypy or not) were not aware of treatment options for these behaviours that did not involve physically preventing the horse from performing them in some way. i.e. weaving bars, crib collars etc. However, owners of horses with a stereotypic behaviour were slightly more aware of them than those without.
These were the main findings of the study and were statistically tested to be significant and therefore can be said to be conclusive despite the small numbers of horses involved. Further findings within the study showed expected trends regarding different management practices and incidence of stereotypic behaviour that supported the conclusive findings of much larger studies (detailed below). These studies have found significant links to certain management practices, the development/ continuation of these behaviours and also ways to treat and significantly reduce these behaviours without further reducing the welfare of the horse in question.
Current scientific thinking on the causes of and treatment of stereotypic behaviours. (adapted by reading available recent scientific research).
Scientific studies have found the following to be untrue:
1. Horses perform these behaviours because they are bored
2. Horses copy or learn these behaviours from others
3. Horses perform these behaviours to get owner attention
Scientific studies have found the following to be true:
1. Horses that are physically prevented from performing these behaviours suffer further reduced welfare and will typically resume the behaviour at a higher rate once the physical restriction has been removed
2. Horses that are prevented from performing these behaviours will often develop alternative behaviours
3. Horses that perform these behaviours are attempting to fulfil a natural function or behaviour and have been prevented from doing so in their past or present environment. The abnormal behaviour provides the horse a measure of appeasement/comfort at the frustration of not being able to perform the desired natural behaviour/function.
4. Due to the reduction of frustration by performing the abnormal behaviour, the horse may learn to perform the behaviour during any period of frustration or discomfort even in situations that are totally unrelated to the original cause of the behaviour, or when the original cause no longer exists. (i.e. a horse weaving in a field) It is likened to a comforting behaviour i.e. sucking the thumb in humans. This can account for horses persisting in performing the behaviour even when all known causes have been eradicated from its life.
Weaving and box-walking
These behaviours are considered to be the result of limited physical, visual and social contact with other horses. Horses are adapted to run in herds and some can feel possibly vulnerable, isolated and stressed when separated into individual stables. The performance of weaving and box-walking is thought to be a frustrated attempt to regain social contact. Therefore studies have shown that horses that can both see and touch other horses whilst in the stable are less likely to develop these behaviours.
Treatment options
Weaving bars, tying the horse up, things hanging over the stable door etc and punishment methods increase stress and frustration levels, thus further reducing welfare, and possibly making the horse want to perform the behaviour more. The treatment options that address the cause of the behaviour have proved most successful at reducing behaviour. This is probably because they reduce the desire to perform the behaviour. They are:
1. Increasing visual and physical contact possibilities with other horses from within its stable. i.e.
a) Having other horses opposite / next too the weaving horse
b) Having a window / grill put in internal walls between stables
c) By placing a specifically designed* mirror within the stable to mimic visual access to others
d) By stabling in an American Barn system that only has grills as upper internal walls between stables and plenty of physical and visual access between horses.
e) Companion within the stable i.e. if big stable have 2 horses in it or Shetland pony or even goats have been used and helped reduce these behaviours if gradually introduced.
f) Barn housing i.e. loose group of horses within a barn.
g) Increasing turnout with other horses to a maximum and reducing stabled time to a minimum.
(*it is important that mirrors used are specifically designed for use in a stable and do not cover more that half of a stable wall. Manufacturers often advertise in the Horse and Hound magazine)
Wood-chewing, crib-biting and wind-sucking
Wood-chewing is more common than crib-biting/wind-sucking. Many horses will continue to wood-chew and never go on to begin crib-biting/wind-sucking, however both are thought to be linked to the same causes and most horses that crib-bite/wind-suck begin by wood-chewing. One cause of wood-chewing alone is thought to be linked to the natural desire of the horse to ingest a variety of species. In the wild horses would be eating, and digesting for over 16hrs a day and can ingest up to 20 different species of forage in order to gain a varied diet. Diets we feed our domestic horses are often limited in variety and therefore it maybe horses are just trying to fulfil the need to ingest more species.
Crib-biting/wind-sucking is specifically linked to forage and concentrate feeding regimes. Whilst stabled, horses' stomachs can often be empty for many hours at a time due to limited forage. Therefore, acid levels can increase in their stomach/gut making them feel uncomfortable and increasing stress levels. The horse may then try to ingest more forage by chewing wood or available materials to make them feel full thus reducing the discomfort/acid or they begin to perform crib-biting/wind-sucking behaviours which significantly increases the saliva flow to the stomach/gut thus reducing the acidity/discomfort. These behaviours can begin through abrupt weaning methods of foals due to sudden diet change.
Treatment options
Cribbing collars, neck surgery, foul substances painted on surfaces, electrifying surfaces etc and punishment increases stress and frustration levels, thus further reducing welfare. These methods do not address the cause and reduce the desire to perform the behaviour. Treatment options that do address the cause of the problem have proved most successful at reducing behaviour without reducing welfare. They are:
1. Feeding as much as possible of the horses' energy requirements in the form of forage and less in concentrates (that are known to move fast through the horses digestive system).
2. If possible feed ad lib forage whilst in the stable. If not possible, feed little and often so the stomach/gut does not stand empty for long and in a format the increases feeding time, i.e. small holed haynet.
3. Feed an equine ‘antacid' feed supplement that reduces stomach acidity. These have been shown to significantly reduce crib-biting and wind-sucking behaviour.
4. Feed a variety of species of forage, i.e. bought food, long or short chop forage or pick non poisonous branches / twigs / logs from the horses field and place in stable for suitable chewing material and alternative species ingestion.
5. Increase turnout to a maximum to allow maximum time for natural foraging and digestive action.
If the above treatments for any of these behaviours do not reduce behaviour then it could be the case that they have now become ‘comfort' maladaptive behaviours that are no longer linked to the original causes.
As an owner of an affected horse the best advice available at present is to treat as above as much as possible to ensure the causes are no longer present, don't try to physically prevent the behaviour (as this reduces welfare and increases frustration possibly also triggering behaviour persistence), and try to accept it as part of the horses behavioural repertoire owing to its past experiences and not its present ones.
Thank you once again for taking part in the study. I hope some or any of this information is interesting or useful. If you would like a copy of the above please email me at hollysue_2000@yahoo.com"
Sue Allen. MSc BSc (Hons)
Added on: 18/05/07.
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