Microsoft word - head flicking.doc

Head-Flicking/Shaking

Now this is a difficult one. Something, the most likely candidate being a neuro-toxin, causes
damage to the trigeminal nerve. This is a major facial nerve which goes from behind the eye down
the face and branches out to the nostrils and mouth areas. Once it is damaged, increased blood
supply, such as on exercise, triggers ‘electrical’ sensations down the nerve, causing the horse to
incessantly flick his head. At first you are sure that a bug has flown up his nose. Flick, flick, flick,
then suddenly, simultaneously, they put the brakes on and rub their nose on their lower leg. This
is quite likely to happen while you are cantering along. It is so exasperating and believe me,
nothing you do will prevent the behaviour.
Head-flicking can be triggered by any kind of ‘pressure’, (mental or emotional type pressure).
Large vet bills, many hours on the internet, trying nose-nets and UV masks follow. The latter
provide temporary relief for some horses.
Over a period of a year or two, the bouts of head-flicking get worse and more frequent. They even
become “photic”, in other words triggered by sunlight and/or breezes. Not a sign of a flick on
overcast days and unrideable on sunny days. One such horse that I know, could be ridden at night.
Eventually the horse is exhibiting these behaviours while at rest in the pasture. It must drive them
NUTS. It gets to the point where the horse is so distressed he is shoving his head in the hedge to
get away from the light, and the owner reluctantly decides to euthanase him.
Personally, I am 100% convinced that the neuro-toxin comes from the rye-grass. And there has to
be some connection between the UV sensitivity, as in the photosensitization, and the damage to
the nerve. It will become clear eventually. Globally nobody knows exactly what causes it, but if
you follow the gist of all this rye-grass stuff, you’ll understand why the rye-grass has to be a
strong candidate. I think the plants with the photodynamic pigments like rye, clover and lucerne
act as ‘triggers’.
From The Survey, 90% of the head-flicking horses were grazing rye/clover mixes, most on dairy
or ex-dairy. (The other 10% did not know, but from the other symptoms their horses were
exhibiting, they most likely were grazing pasture that contains rye-grass). Most were on rye-grass
that has been fertilized with super, but some were on pasture that hasn’t seen fertilizer for 10
years.
One quarter of the horses for whom their owners filled out an “Equine Health & Behaviour
Survey” are head-flickers. (42 out of 170). I have heard of two horses whose head-flicking started
after an accident that must have damaged the trigeminal nerve.
All the head-flicking horses from the Survey also exhibit other symptoms of myco-toxicity.
I know of several horses that flick when on rye-grass but cease to do so when taken off it.
The only two horses that I know of that have been completely removed from rye-grass/clover and
are now grazing cocksfoot type pasture, are both virtually flick-free. One of these horses belongs
to me.
Head-flicking does not seem to respond to a toxin-binder, even large doses. It can be seasonal, but the only hope seems to be complete removal from rye grass. Drastic measures such as blocking or cutting the nerve, give about 4-5 years of flick-free riding, but apart from the risk of a droopy lip, when the nerve repairs somewhat, it comes back worse than ever, and that is the end of it. There are some expensive drugs (cyproheptadine) that can help in some cases, but again not long term. It does seem ridiculous to go to such measures when maybe just removing the horse from the offending pasture could be the answer. With my horse, even tho he is now basically flick-free, I am sure damage to the nerve still exists, as some flicking can still be triggered by increased exercise, as when I gallop him and get him warmer than normal, or if he gets his knickers in a twist about something (pressure). Maybe the damage to the nerve will gradually repair completely, providing he is not exposed to the irritant again. Certainly, whatever it is that causes it to become photic is gone. This could be to do with the fact he is no longer grazing the grasses that contain the pigments which cause photosensitization. I will be holding my breath when spring comes. Please e-mail me with your story and anything you have found that helps.

Source: http://horsemanshipnz.signplus.net.nz/articles/headflicking.pdf