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Vet Forum: The Expert View two are linked, but one does not cause the other. In one study, the development of colic was linked not only to an increase in crib-biting, but also to the stabling of the horses off grass in Autumn, and again in this situation both the cribbiting and the colic could be attributed to a lack of the horse’s ability to graze, rather than the time of year. This is the problem with associations in research. As a direct result of the finding that stomach ulceration and increased acid was linked to ‘cribbers’, further research showed that feeding of antacids to these horses reduced the behaviour significantly. This suggests that the horses are crib-biting because of the increased acidity and ulceration in their stomachs, rather than the latter being caused by crib-biting. Several anecdotally effective commercial products are now available, aimed directly at producing stomach comfort, but with the intended end-result of reducing cribbing. There is even some evidence that cribbing may increase saliva flow into the stomach, bicarbonate rich saliva being a natural antacid.

How can we stop it?

Treatments aimed at reducing cribbing include invasive surgery (see inset box) making the horse physically incapable of grasping a fixed object, and gulping air. Given that we have already noted that cribbing is a need in the affected horse, and actually helps them cope with the inappropriate environment, is a surgery that physically prevents them from being able to carry out the behaviour not tantamount to cruelty? For the same reason the fitting of anti-crib biting collars should be discouraged. These work primarily by punishing the horse for attempting to crib-bite. They do so by the pain experienced by the horse in attempting to arch the neck. There is no doubt that in many horses these collars are effective, but should we be using them? In one study, two research workers who have led the way in this field, Christine Nichol and Paul McGreevy, assessed the effectiveness of anti-cribbing collars in eight horses. They found that the collars prevented the activity in six of the eight, but when the collars were removed after 24 hours, these horses showed a rebound in crib-biting behaviour, increasing it well above the frequency

COURTESY OF PROF. PAUL MCGREEVY, UNIVERSITY OF SYDNEY

›› of wind-sucking and colic. So, yes, the

Figure 2: A graph showing the incremental crossover between sucking (blue) and grazing (red) that happens very gradually during natural weaning. Preventing this may encourage the development of ‘cribbing’

seen prior to prevention. In one study using an even more harsh method of inflicting pain on cribbiters, they were fitted with a device that gave an electric shock every time they ‘cribbed’. Sixty horses were enrolled on the study. At first sight, it seemed to have a very high cure rate. However, long-term follow up of these horses showed that only nine were persistently ‘cured’ and of those, three required further re- enforcement at nine months, so only 10% stopped cribbing long term. In other words, these horses clearly have a motivation and need to crib-bite. When they are prevented from doing so, once the prevention mechanism is removed, they are even more keen than previously to crib-bite. Behaviours of this sort are usually thought to be functional, (i.e. have a useful purpose), so then is it wrong to try to prevent such behaviour?

Prevention is better than cure

We know for certain that once cribbiting is established it’s very difficult to eradicate. The emphasis therefore has to be on the prevention. One large study in Switzerland showed that the biggest steps we could take are to allow horses increased socialisation and tactile contact (mutual grooming is a normal part of behaviour in groups of horses housed outside). Free

movement in the paddock also had a preventative effect, as did the feeding of a high roughage diet with little or no concentrate. In the thoroughbred racehorse, most of these are difficult or impossible to achieve in the adult, but some steps could be taken in this direction. For instance, having a grill-panel between adjacent boxes, which allows horses to see each other without being able to bite or kick. Similarly, the provision of ad-lib forage between concentrate meals, so allowing them to forage whenever they feel the need to eat, rather than to have to wait until we decide it is time for them to do so. The main push however has to come in the young foal, at or around the time of weaning, when this behaviour often establishes. Great effort should be made to make the weaning period as stress-free as possible. Weaning should always take place in groups, out in the paddock, so that the foal which has just been prevented from sucking the dam can immediately turn its attention to grazing (see Fig 2). It is clearly time that we reappraised our ideas about this behaviour and a good first step in this direction would be to drop the term stable vice in its description. Even the veterinary profession have done the horse no favours, coining the ‘posh’ technical term for ‘cribbing’, aerophagia.

94 THOROUGHBRED OWNER BREEDER INC PACEMAKER

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Incorporating Pacemaker - July 2018 July's issue features a fascinating interview with Chasemore Farm's Andrew Black who is making his mark...

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Incorporating Pacemaker - July 2018 July's issue features a fascinating interview with Chasemore Farm's Andrew Black who is making his mark...

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