Headshaking

By Dr. Lydia Gray on December 31, 2008 at 2:41 pm
Behavior

My horse started shaking his head like there is something wrong with his inner ear. I did just see a chiropractor and found out he has a lot of back problems. I also had his teeth floated about 2 weeks ago. Something is really bothering him. He does have alot of stuff in his ears, but not wet, more powdery. Thank You. KY, Nevada

Dear KY,

I take a lot of ribbing here at SmartPak because in many of my answers to questions, I mention that I know a lot about the topic because one of my horses has the same problem. Fortunately for you, that’s the case here. My seven-year-old trakehner gelding displays all the signs of a classic “headshaker”:

• Flipping the head up and down in a vertical plane
• Snorting and sneezing
• Raising the upper lip
• Rubbing the muzzle on the ground and other objects
• Wiping or striking the face with a foreleg
• Anxious facial expression

Does this sound like your horse or does yours shake his head in a different way? Regardless, the first step is having your veterinarian perform a thorough physical examination. Sometimes horses that shake their heads do have a problem in their ears that can be treated and the shaking goes away. Other times, no physical problems can be found and the horse is dubbed a “headshaker.” Your veterinarian will carefully examine the eyes, mouth, head and neck, and perhaps even take an X-ray of the skull to check for fractures. Other possible tests include “scoping” or using an endoscope to visually examine the guttural pouches and upper respiratory tract.

If there’s no obvious reason for your horse to have pain or discomfort, your veterinarian may perform a test to determine if bright light is a trigger factor. Owners of headshaking horses often report that signs are worse in broad daylight. That is, when a horse is ridden indoors or at night, there is very little headshaking. But when the horse is worked outdoors in bright sunshine with the same tack, rider and level of exercise, the horse shakes its head or performs one of the other signs in the list above. The theory is that headshaking is a photic, or light-stimulated, response. Much like some people sneeze when they see a bright light, some horses headshake. This may have to do with stimulation of a nerve in the face called the trigeminal nerve. If stimulation of this nerve in horses is anything like stimulation of the nerve in people, experts believe horses feel a tingling, itching or burning sensation in their muzzle.

As you’ve probably figured out, keeping a journal of exactly what your horse does and when he does it can be very helpful in figuring out WHY he does it. And if you can figure out why he does it, you may be able to prevent it. For example, if you and your veterinarian determine that light does indeed provoke his headshaking, then you may want to ride him inside during sunny days or work him at night. Or you may want to try a special fly mask that blocks UV rays. Also, nose nets that cover the muzzle have been shown to help many horses, probably because they physically touch the part of the horse that feels “funny” and distracts them from the nuisance.

While there are no medications that treat headshaking, some horses have improved on the pharmaceutical cyproheptadine. Carbamazine and fluoxetine have worked on other horses. Antihistamines, steroids, NSAIDs have not shown any benefit. Owners have also tried acupuncture, chiropractic, homeopathy and other remedies, usually unsuccessfully. You may want to talk to your veterinarian about using melatonin, lysine or topical anesthetics. Finally, don’t be afraid to make changes in your tack or training methods, as some horses have improved when switched from a bit to a bitless bridle, and others have been able to be reconditioned or retrained not to headshake. I do want to make the point that if your horse is a true headshaker, this is an involuntary response and not something he should be punished for. Your job is to patiently and systematically eliminate any potential sources of irritation in the hopes the behavior isn’t triggered.