Horses shake their heads for a variety of reasons, some normal, some related to obvious sources of pain and some cases apparently to extremely unpleasant sensations. Headshaking when you’re riding is at best annoying and at worst downright dangerous.
To deal with it correctly, you have to systematically rule out potential causes. It makes sense to start with the most likely causes and work your way up. First check to be sure the horse is not experiencing any type of pain or irritation that can be corrected. Some horses have a good reason for flipping their heads, and if you don’t correct the cause early on it could become a behavior problem.
A horse that shakes/flips his head only when ridden may do so as a response to physical pain or rider error. A rider with rough hands, one that relies too heavily on their hands and isn’t backing up rein signals with appropriate body position and weight shift — or giving mixed body and rein messages — and one whose balance isn’t good and doesn’t sit lightly in the saddle may result in a headshaking response.
Ill-fitting bits or mouth sores, saddles that pinch, back pain and hind-end lameness pain anywhere from the pelvis on down can also cause headshaking.
In all these cases, the behavior will disappear when the horse is in the barn or turned out or free-longed. Horses that headshake in response to pain may go better with a quieter rider, but the behavior can return if the horse is asked to accept the bit, flex at the poll, or engage behind, depending on the location of the actual pain.
Ear or poll pain can make a horse headshake when bridled, longed on a line. or led. Previous trauma, such as caused by going over backward, may cause joint, ligament or bone problems at the poll that result in chronic pain. Inflammation of the bursa at the poll, either from poorly fitted head gear or even a systemic infection, is another common source of pain that causes headshaking.
Ear mites, ear ticks and ear infections could also be the problem. These horses will more than likely also be head shy and/or resistant to being bridled or haltered, even brushed or touched around the poll or ears. If these signs are present, a veterinary exam, including the interior of the ears, should be done.
Once you’ve ruled out pain and irritation, consider if the headshaking can be a behavior or training issue. When it’s a behavior issue, you’ll see it in any season and under many different conditions. The movements the horse makes also tend to be characteristic and repeated consistently. Some swing the head from side to side, and some roll it around. Still other horses flip their heads up and down.
Some horses have a strong tendency to shake/move/flip their head as an expression of excitement or annoyance at conditions like waiting to be fed or standing on crossties. Situations that might make most horses paw make some horses express themselves through head movements. These are training issues that should be dealt with the same as you would a horse who paws or refuses to stand in the crossties.
Others do it deliberately to jerk the reins from the rider’s hands. You can likely think of an obstinate, novice-savvy pony who has this down to an art — maybe even good enough to dump the rider right over his head when the horse combines the flip and jerk with lowering the head to the ground. You’ll often find that putting an experienced rider on the horse or pony slows or stops the problem.
Behavior-related headshaking can progress well beyond annoyance, excitement and obstinancy so that the horse becomes nearly unrideable.?? A horse with a dominant Type-A personality can quickly find that repeatedly tossing the head leads to a gratifying battle of wills with his usual rider, even an experienced one.????
The rider may turn to a standing martigale for safety, but it doesn’t solve the problem. The best solution is to under-react rather than join in the fray and to keep the hands still.?? The behavior will then gradually subside over a few days or weeks.??
Headshaking As A “Disease”
A few headshakers have no personality/training issues or obvious causes of pain. These horses are notoriously difficult to correct or treat. Several studies have identified characteristics that can be used to put together a profile of a true headshaker horse, including:
• Obvious seasonal pattern (spring and summer) in about 60 to 70%.
• Headshaking present at rest, at exercise and when excited.
• Both vertical and horizontal headshaking.
• Flipping the nose, acting like a bee just flew up the nose, snorting.
• Rubbing the nose on the ground when stationary and when in motion.
• Rubbing the nose on objects.
• Striking at the nose with the foreleg.
Horses with true headshaking problems will exhibit several, but not all, of these symptoms rather than just one or two. The behavior is also almost constantly present, often described as violent or seemingly beyond the horse’s control. It definitely goes beyond something that is merely annoying to a significant interference with training. It may even make the horse unsafe.
Several research studies have shown that geldings are more likely than mares to develop headshaking. Headshaking may begin at any age, but the median age is believed to be around nine years.
While veterinarians and researchers are better at confirming a diagnosis of a true headshaker than they were a decade or so ago, the debate rages on about possible causes and treatments. These horses certainly act as if they’re experiencing an irritating sensation, and most veterinarians agree this originates either in the respiratory passages or from sensory nerves.
A history of allergies is common with headshakers. Many horses act as if they have severe itching or burning, and some may even have a nasal discharge. Photic headshaking — triggered by strong sun, a sort of sun allergy — is another strong possibility. Photic headshakers classically only show the behavior when ridden or turned out in direct sun and usually avoid the sun.
It’s been theorized that seasonal hormonal changes in the horse’s brain with increasing day length may heighten sensitivity of the trigeminal nerve, which supplies the structures of the horse’s head, including the nasal passages.
The theory is that normally innocuous stimuli like light, gentle touch, wind, air flowing with force along the nostrils as when being ridden, and possibly inflammation associated with allergy may trigger intense pain in the horse.
Research is ongoing to investigate the possibility that rhinopneumonitis vaccination may trigger headshaking in some horses. Since the equine herpes virus that causes rhinopneumonitis often remains in the horse’s body as a latent infection, the theory is that vaccination may stir up the immune system enough to cause inflammation of nerves that may be harboring the virus.
Regardless of the cause, unless a genuine allergy or other problem can be found, research so far is pointing strongly to severe pain and/or other intense sensation originating from hypersensitivity of the trigeminal nerve.
Although probably the least likely cause, EPM is also possible. A 1997 report from the University of Missouri described headshaking in association with abnormalities on neurological exam and positive CSF tap. The headshaking resolved with EPM treatment. Whether it was truly due to nerve involvement with the EPM or a manifestation of the horses’ frustration is unclear.
Other rare causes include un usual parasite infestations or tumors in the nasal passages or sinuses. Tranquilizers can help control the symptoms in some horses but aren’t suitable for horses in work or long-term, and their effectiveness may decline and disappear in a short time.
Horses suspected of having seasonal plant or pollen allergies should be skin-tested and desensitized, if possible. Usually, however, a trial of antihistamines and/or steroid nasal sprays are tried instead. Many horses will experience some relief from these measures, but few are cured.
True photic headshakers may respond to hoods that shield the eyes from light. Many headshakers obtain relief from wearing a net or piece of fabric over their nose. This may work because it avoids extremes of air temperatures entering the nostrils, helps filter out dust and pollen, protects the sensitive skin of the nose from overheating (sun) and wind, and decreases the turbulence of air in the nasal passages.
On the medication front, cyproheptadine is commonly tried with headshakers. Since it’s an antihistamine, it will help with allergies. Interestingly enough, cyproheptadine also has hormonal effects in interfering with serotonin’s actions in the brain and with epinephrine. It helps with human nasal irritations that are caused by reflex overdilation of the blood supply to the nose.
Cyproheptadine appears to be of particular benefit to horses with photic headshaking. Horses that aren’t obviously allergic or photic headshakers respond poorly or only partially to cyproheptadine treatment.