At this time of year, vets report a dramatic increase in the number of horses showing signs of “headshaking”. This is a significant neurological disease and shouldn’t be taken lightly. The abnormal movements range from small “tics” to severe and distressing jerking of the head. Most horses will shake their heads up and down, a few may show side-to-side or rotatory head movements. The key point is that it is involuntary. Voluntary head tossing, demonstrated by some horses in an excited manner, can be natural “showing-off” behaviour, not headshaking. In the past, headshaking was considered a behavioural issue, often blamed on poor tack or horsemanship. We now know that this is not only wrong, but is also a cruel and unnecessary approach to a seriously ill horse.
One of the problems that is commonly thought to cause headshaking is damage to part of a sensory nerve supplying the skin of the face (including muzzle and ears), teeth, eyes, sinuses, and nasal cavity. Usually the brain receives information from these nerves about certain environmental factors (touch, heat/cold, air movement etc.) and it then makes decisions on how to respond. One theory about headshaking is that these signals become distorted and the brain perceives them in an abnormal way which then causes an excessive response.
Most treatment is based around trying to determine the initiating cause and limiting the horse’s exposure to those. Nose nets, ear covers, and various other options have been used with varying degrees of success. Various nutritional supplements look to help with maintaining comfort levels, decreasing the immune response if an allergic component is suspected, and also attempt to soothe the nerves affected.
The most recent advancement is a treatment used in people for facial neuropathic pain. This is called neuromodulation, using Percutaneous Electrical Stimulation (PENS) therapy and it aims to re-set the threshold level for the affected nerves firing to normal. This involves placing a probe directly over the nerve and stimulating it for a set period of time. In people the only reported side effects are a bruise at the site of probe insertion.
James Evans BVetMed MRCVS
Technical Manager, Global Herbs
James qualified from the Royal Veterinary College, where he then became part of the Equine Referral Hospital team as one of the Junior Clinical Training Scholars. He then worked at various practices in the Home Counties, working with some of the top polo teams, event and competition horses in the world. It was during this time that James developed his interest in complementary medicine and nutrition and went on to develop extensive understanding of the needs and requirements of all varieties of horses. He is now the Technical Manager at Global Herbs Ltd. James is an FEI Permitted Treating Veterinarian. He presented his final year research project at the International Congress on Equine Locomotion in Stromsholm, Sweden and has also been published in the Equine Veterinary Journal.
He operates the advice line for Global Herbs and is available for technical advice on 01243 773363