To date, headshaking has proved to be one of the most frustrating problems for riders and affected mounts. In the search for a cure, owners and the worldwide veterinary profession have ridden the rollercoaster of hope as each new treatment is touted, then found to work in just a small number of cases.
What are the possible trigger factors?
The root of the problem is now thought to be the trigeminal nerve, a cranial sensory nerve (one that helps you to feel) which produces a pain that cannot be treated with painkillers. In people, trigeminal neuralgia causes intense irritation and pain (resulting in symptoms similar to those exhibited by horses) and it can be triggered by something as simple as looking at a red traffic light.
The difficulty is that, while a person can help you to pinpoint the trigger and map the centre of the pain, this is not an option with horses. The trigger may be via the horse’s nose, ears or eyes, or it may be stress-related.
How to recognise a true headshaker
On a classic headshaking day (bright and sunny in the spring or summer), the horse will flip its nostrils and upper lip.
When ridden, and usually as you start to trot, you may find that the head starts to toss about uncontrollably and your horse becomes very distressed.
The typical movement is unmistakable. It is violent and the horse behaves as though it has a bee up its nose. As you ride forward, its head will suddenly go up and then sharply down, accompanied by a loud clearing of the nostrils. The horse may also strike out with a front foot.
Sometimes, the head movement will be side-to-side. In severe cases, the horse may dive at trees in an attempt to rub its head, or may drag its nose along the ground. Even in the stable, some horses will wiggle their muzzle.
Should your horse appear to start shaking its head in an agitated manner, the first thing to establish is that it is, in fact, a true headshaker. Watch out for the following:
Have you moved to a new yard?
Is there a large amount of oil seed rape in the vicinity?
Has the horse suffered some trauma?
Have you changed your tack, or way of riding?
Have you recently removed a long-term companion?
If you believe you have a headshaker, look back over the past year to see if anything has changed and ask yourself the following questions:
As a consequence of your investigations, you may want to experiment with your management routines or change your riding patterns – for example, ride in the early morning or late evening, or try to stick to indoor venues, if this helps. Other horses may show an improvement on open ground such as a beach; some are better with more work, some with less.
Unfortunately, in certain cases, riding is not an option: Liverpool Veterinary School followed horses referred to the school for five years, and four out of 11 had to be retired. Some owners may face the decision to have the horse put down if it is considered dangerous.
Tips for managing a headshaker
Always buy a horse in the summer or, get the owner to sign a declaration that the animal is not a headshaker. Remember, however, that should the problem start the first spring you own the horse, you would still have to prove that its previous owner knew about the condition.
Few would advise buying a known headshaker, as not only does the disease often get progressively worse, but a bad case can be dangerous.
Buy a nose net. If it works, you will be able to ride your horse as normal. The nose net produced by Equilibrium is the only one allowed in affiliated competitions.
Be wary about looking for solutions on the internet – as yet, headshaking has no known cure and many sites offer umpteen different remedies.
Try moving your horse to a yard in a new area. The change in environment may remove the trigger for an attack, and a move has been known to solve the problem in some cases.
Other options include:
Guardian Masks from the US (visit: www.guardianmask.com). These masks cover the horse’s eyes, excluding ultra-violet light. This may alleviate the problem in horses whose headshaking seems to be triggered by light.
Allergy testing and hypo-sensitisation. Some vets may be willing to send off blood samples for allergy testing. Results are followed by a course of injections aimed at desensitising the horse, which can take up to a year to complete.
Rubbing the horse’s nose in vinegar and oil or getting it to inhale Friar’s Balsam before riding is said to help in some cases, as the fumes may have a dampening effect. Using sunblock on sensitive pink noses has also helped some patients.
Non-veterinary approaches include using Advanced Protection Formulae, which includes Eleutherococcus senticosus (Siberian ginseng), Schizandra chinensis (Chinese magnolia vine), Rhodiola rosea (golden root), and Echinopanax elatus (Asian devil’s club). APF is imported from the US by Courtney Hart, tel: (01423) 772 872, and is also sold by Annabelle Knight, tel: (01444) 236 263.
The past ten years have seen a large amount of research into headshaking, especially by Tim Mair, Dr Derek Knottenbelt at Liverpool Veterinary School (left), and vets Daniel Mills and Katy Taylor at De Montfort University and subsequently Lincoln University.
The latter undertook the National Equine Headshaking Survey(NEHS) in 1997 and has an excellent website with a lot of practical detail on the disease, go to www.lincoln.ac.uk/dbfs/research/headshaking
The NEHS found that:
Most sufferers started showing symptoms between five and seven years of age.
63 per cent of the horses were seasonally affected, and 29 per cent of those horses were headshaking for longer periods each year.
A greater proportion of geldings were affected seasonally, and seasonal shakers were more likely to flip their nose about and react on sunny days.
To read this article in full, see the July issue of HORSE, on sale now