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An Overview of Headshaking Syndrome in Horses

Meghna Wani
Headshaking or head tossing is believed to be a normal and natural defensive reaction, in which the horse makes voluntarily movement of the head to ward off flies. Let's find out through this story, if headshaking is just an anti-fly reflex action, or a neurological disease.

Causes of Headshaking!

Headshaking can be triggered due to many external stimuli, like flies, light, exercise, sudden loud sounds, certain smells, and some long-stem hay types that the horse may be allergic to.
Headshaking is a syndrome that can be very traumatizing for the horse as well as the owner, because the owner is neither able to ride an otherwise healthy horse, nor does he understand the reason behind why it's happening. When it comes to riding, they start doubting their own riding ability and end up thinking that their hands are rough. 
And the horse keeps suffering silently, as it is not able to express its pain. This is where PetPonder thought it would barge in, and make the owner/rider aware, by giving an overview of the horse headshaking syndrome.
Horses often shake their head, more so, when they are at rest. It is usually in the form of side-to-side, vertical, or rotatory motion, and is as if a bee has stung its nose. If this behavior starts happening when the horse is galloping, then it should be taken seriously, because this type of behavior can be dangerous for the rider.
If headshaking becomes frequent, violent, and to an extent where it interferes with the quality of life of the horse, then medical intervention may be required.

Headshaking as an Anti-fly Reflex

A normal, healthy horse has a very small enemy – the fly. To shoo them away, the horse uses various mechanisms like swishing of its tail and flicking of its ears. Its body is also covered with a layer of panniculus muscles just under the skin. These muscles twitch or react when a fly sits on the horse.
But these muscles do not span the lower legs, the neck, and head area. If the fly sits on the lower legs, it is driven off by stamping of the foot, and if it sits on the head or neck, shaking the head is the only option available for the horse.
Headshaking costs the horse a lot of energy. Therefore, horses have learned the technique of switching off the fly-defense system when flies are not around. But how does the horse come to know that flies are not around? It is by the presence of sunlight and warmth.
If it is taken to a dark barn, it automatically shuts off its anti-fly mechanism, and stops shaking its head. So, the next time you see a horse shake its head, and if the season is spring, summer, or fall, remember that it's using its first line of defense against these pests.
But this is not always the case. You may have to observe the horse more carefully. If you find that the headshaking movements are increasing, and are accompanied by other actions like rubbing the nose on the ground or hiding the face behind the tails of other pasture mates, then perhaps you may have to dig deeper to find the underlying cause.

Start Observing the Horse

You may have to follow this step religiously. Start by observing the horse, when it is in the stable or at the barn. If he shakes his head in bright sunlight or artificial light, then the horse may be suffering from 'photic headshaking'. In this type of headshaking, the bright light irritates the trigeminal nerve of the horse's face.
Thus, it may shake its head to get relief from the sensations like tingling, itching, or burning. The horse may even snort or sneeze, flip its upper lip, and rub its muzzle against the ground or with the foreleg.
Such horses usually prefer shaded areas, or at least want to keep their head in shady areas. You have to observe everything very minutely. If it is possible, you can also videotape it, to show it to the veterinary doctor.
If the horse keeps shaking its head even while riding, the first action should be to loosen the reins a little. Try doing this; it may possibly reduce the headshakes. Too tight control or continuous whips can be a reason why the horse may shake its head violently.
The next step would be to check the bit. See if it is pinching the horse's mouth. The main idea is to be subtle, and try to keep the horse as comfortable as possible.
Having an equine dentist visit your horse to do a thorough oral checkup may help. Some shallow-rooted or sharp and pointed teeth may interfere with the bit, and could cause pain. This pain can also be one of the reasons the horse keeps shaking its head.
An uncomfortable saddle can also be one of the reasons of headshaking in horses. The horse may experience back pain because of it, and may shake its head to relieve the pain. It is likely that a variety of triggers can act together to cause a reaction.
Besides videotaping, it is also advised that you maintain a diary, in which you can make a record of the instances in which your horse shakes its head, and show it to the vet.

Visit an Equine Doctor

If your feel your horse has become a headshaker, no matter if he is in the field or in the barn, then it may be time to get in touch with the veterinary doctor, and go through a complete physical examination. Problems in the eye, ear, and mouth, fractured bones, infections of the respiratory tract, and neck problems, can be the reasons behind the condition. 
An endoscopy of the nose, the airway, radiographs of the head, and the standard blood examination can be done to determine the underlying cause of the syndrome. It is seen that headshaking is a type of primary symptom for more than 60 diseases in horses.

Physical Methods

If you figure out that your equine's headshaking is mainly photic, and gets aggravated during bright and sunny days, then an ultraviolet-blocking mask with ears would help. If you think that a swarm of flies is what is bothering the horse, then a fly mask with ears and a nose piece can significantly reduce the headshaking.
If you think that your horse has gained weight, then may be increasing exercise may also help in reducing the headshaking. But again, a word of caution. If the horse has become heavy, a sudden onset of heavy exercising may increase its blood pressure, and in turn, exasperate the behavior.
Be easy with the horse, and do not encourage a spur. It is seen that high energy levels, spurs and whips, build up resentment, and it may respond by violently shaking its head.

Supplements May Help

Only after a thorough checkup is done by the vet, can supplements be incorporated in the diet of the horse. Supplements are of various types. First is lysine, an amino acid that provides relief to horses suffering from the syndrome. A strain of equine herpes virus known as rhino, can cause headshaking in horses, and lysine can inhibit its growth.
Second comes melatonin, which is a hormone secreted in horses in winters. As the days get shorter, their melatonin levels go on increasing, and reduce as spring approaches. If the symptoms of headshaking are seasonal, and get aggravated in spring and summer, then supplementing the diet with melatonin may help.
It would confuse the horse's body to think that winter is still present, and eventually lessen the headshaking.Third are antioxidants. If the headshaking is due to damage to the trigeminal nerve, then supplementing the diet with antioxidants like vitamin E can help. Oral magnesium supplements have also shown to provide some relief for many horses.
The correct dosage and the way of administration of the supplements should be done only after consulting a veterinary doctor. Self-diagnosis may harm your equine with some serious side effects.

Prescription Drugs

There are a number of drugs that can be used to minimize the headshaking symptoms. If neuropathic pain is the reason, then cyproheptadine, an antihistamine, can be administered. Most horses improve on cyproheptadine. 
A combination of carbamazepine or fluoxetine and Atarax (hydroxyzine) can also be given. Non-steroidal anti-inflammatory drugs (NSAIDs) and steroids could also be used to improve the horse's condition.
Some topical anesthetics, when applied directly to the face, can also relieve the symptoms and lessen the headshaking. A few other forms of therapies like homeopathy, acupuncture, chiropractic, and aromatherapy can also help, but its effectiveness is still not proved.
I would again like to mention that before you make any alterations in the horse's daily routine or dietary regimen, it is very essential to consult a veterinarian.
If training or its tack are the reason behind the discomfort, loosen it or adjust as necessary, and if any medical condition or injury is causing it to shake its head, then probably your vet is the best bet.