Stereotypies

These behaviours have been linked to different health problems, including excessive wear of teeth, and difficulty in keeping weight on. As opposed to a common preconceived idea, X rays have shown that the horse does not in fact swallow any air during wind sucking, but sharply distends his oesophagus.

It has been suggested that cribbing or wind sucking could increase salivation, and reduce gastric acidity associated with a ration high in concentrated feed. Saliva has a buffer effect on stomach acidity. The high incidence of gastric ulcers in rationed horses (receiving a high level of concentrates and not much hay) is now a recognized fact : 82 % of race horses have lesions, as do 51 % of thoroughbred foals aged less than 3 months.

The potential link between these stereotypies and the presence of ulcers is suggested on the basis of several studies. These studies demonstrated that administering antacids which improved the state of the stomach, also reduced the frequency of the stereotypical behaviour, which often occurs after a feed (during digestion). Moreover the appearance of both pathologies is clearly linked to the stress felt by the individuals. Thus, certain horses and certain breeds develop more ulcers, more stable vices, or are more subject to colic than others, as they are more sensitive to stress.

Weaving and head bobbing are two frequent types of locomotor stereotypies.

In the case of weaving, the horse shifts his weight from one forelimb to the other creating a « swaying » movement. Horses usually do this standing behind their stable door.

Stall walking is another locomotor stereotypie : the horse keeps walking round and round in his stable.

• Not enough forage (less than 6,8kg for race horses) and a too high proportion of concentrated feed ;
• Stable design which restricts contact between horses ;
• Restricted movement (stabled horses) ;
• Impoverishment of the horse’s living conditions (absence of sensory stimulation).

Additionally, the impact of weaning is considerable. It is a particularly stressful time for the young animal, and linked to many changes such as a brutal break with the mother, a change in  diet, new living environment, a new social group and very often more frequent contact with humans. A long term study has shown that foals who develop crib biting, start to show signs on average at around the age of 20 weeks. The authors emphasize that after weaning, foals who are fed on concentrates are more subject to developing cribiting habits, than those who are not fed on concentrates.

Although feeding concentrates can help the foal from a nutritional point of view, it could also compromise the health of the gut lining, and does not replace the behavioural need to suckle. The strong need to suckle could cause the appearance of crib biting.

Restricting movement could also be the at the root of behaviour such as stall walking. A study has shown that horses who come out of the stable for exercise every day are explosive when turned out in a paddock at weekends, whereas horses who are exercised every day, but who are also turned out every day, are much quieter in the paddock. This need for movement could also appear when ridden, and therefore be detrimental to the rider’s safety.

Giving a sufficient quantity of  hay is essential to avoid the onset of stereotypical behaviour, as is promoting contact between stabled horses.

As crib biting tends to develop in weanlings, weaning conditions should be improved to lessen the stress (which can cause ulcers). For example have an older calm horse grazing with a group of weanlings is a good way to limit the foals’stress. Additionally, foals should be fed on a high fibre diet.

Regarding adult horses who crib bite, the owner should maximise the time spent out grazing, and the quantity of fibre in the horse’s ration. This induces chewing for longer periods of time : when the horse is busy eating he does not need to find a substitutuion activity, and will therefore be less inclined to develop stable vices. In addition, chewing reduces gastric acidity. Unfortunately, restoring a fibre based diet does not always solve this type of problem. It is therefore recommended to check that horses who crib bite or wind suck do not have gastric ulcers. If there are ulcers, medication can be given with the horse’s ration, and adding corn oil to the ration may be encouraged.

When addressed as soon as it appears, this type of behaviour may disappear. However, it may persist despite efforts to suppress it, especially in horses who have been doing it for a long time. Indeed, we think that the horse feels a certain appeasement from this behaviour, and therefore continues for this reason. In this case the horse needs to be accompanied to avoid any detrimental effects on his health (worn teeth, weight loss…) The surface on which the horse leans should not deteriorate his dentition, it should therefore be covered in leather or wood.

Lack of social contact is also suspected of being the cause for horses who are excessively aggressive towards other horses, like trying to bite any horse going past their stable, or bucking when another approaches when they are being ridden.

If it is not possible to allow any contact with other horses, mirrors can be placed in the box. These simulate the presence of another horse and contribute to lessening the intensity of the stable vice. Their effect may last several weeks, and could even be permanent for some horses.

Lastly, one should always remember that it is easier to get rid of a stable vice detected early on.