Head Shaking in Horses
There are many reasons why a horse may shake its head. Factors such as sharp teeth, heavy hands, uncomfortable bits and a sore poll or neck may well cause a horse to behave in this way.
However, some horses shake their heads due to sudden bursts of intense pain – like an electric shock running down the side of their face - and characteristically respond to it with a vertical flick or toss of the nose or head and neck. This is due to sensitization of the trigeminal nerve, which supplies sensation to the face, nose and jaw. They often experience muzzle irritation, which causes them to rub their noses on the stable wall, the ground, their front legs or even the rider’s boot. The rubbing may be frantic and result in nasty sores. Affected horses and ponies can sneeze or snort and become very agitated, leading to unpredictable and dangerous behaviour.
The cause of trigeminal neuralgia is not fully understood, but a number of factors are known to act as triggers. These include:
- Ridden exercise
The condition is seasonal in most horses, beginning in the spring and subsiding in the autumn. Once it has occurred, however, the resultant headshaking tends to recur earlier in successive years and some unfortunate animals experience this debilitating and painful condition all year round.
Treatment begins with eliminating as many of the trigger factors as possible. Affected horses should:
- Be stabled during the day and turned out at night
- Wear an ultraviolet light blocking mask
- Wear a fly rug and repellent to reduce irritation from insects
- Wear a nose net and face mask for exercise
- Be exercised at the times it is least sensitive eg avoiding bright sunlight, rain etc
- Checked over for signs of head, neck and dental pain and treated to eliminate these
- Have an endoscopic examination to rule out the presence of nasal tumours, foreign bodies, sinus infection or guttural pouch disease
- The tack (bridle and saddle) must be checked for any source of discomfort
- Where finances permit, x-rays and a CT scan of the head are helpful to rule out any pathology that may cause the head shaking e.g. undetected dental or sinus problems
Some horses improve with medication including carbamazepine and cyproheptadine. However, the results are not consistent and use of these medicines is prohibited in competitions. They are expensive and may make the horse drowsy.
Compression of the infraorbital nerve with a platinum coil placed under general anaesthesia has been used with some success in around 50% of cases. However, a number of horses experience such severe post-operative pain that they require euthanasia, so this is not recommended unless all other options have been unsuccessful.
People suffering from trigeminal neuralgia have reported significant pain relief following treatment with electroacupuncture and published papers on this subject are available in the medical literature. Recently published work from Bristol University Vet School has shown a good result using Percutaneous Electrical Nerve Stimulation (PENS) of the infraorbital nerve using a PENS probe placed near the nerve under ultrasound guidance.
Electroacupuncture can be used to stimulate the nerve in a similar manner, but can be done in the horse’s home environment and does not require expensive equipment.
In April 2015, two severely affected animals were treated with electroacupuncture with encouraging results.
Their owners assigned a grade of severity to the headshaking at the start of treatment and each day thereafter, and these are as follows:
Grade 0 – no headshaking
Grade 1 – mild headshaking when exercised but still able to be ridden or driven
Grade 2 – headshaking too severely to be ridden or driven
Grade 3 – headshaking at rest in the stable/field as well as at exercise
A note was also made of the weather conditions and pollen count wherever possible.
Under light sedation a single acupuncture needle was placed under the infraorbital nerve on each side of the face and a second needle was placed each side of the horse’s neck. An electroacupuncture unit was attached and treatment was given for 20 – 30 minutes.
Each animal was given an initial treatment when the symptoms developed. A second treatment was given a few days later if there was no improvement or else when the symptoms recurred. Subsequent treatments took place as necessary until the horse or pony was able to resume its normal work without any headshaking.
Here are their stories:
Izzy was 15 years old at the start of treatment. She is a Trakehner mare that competes successfully in affiliated dressage. In the summer of 2012 she became unrideable due to headshaking. The condition recurred earlier in subsequent years so by the end of March 2015 she was once again unrideable. Prior to commencing the treatment, Izzy was given a full veterinary examination including a dental inspection, endoscopy and a chiropractic assessment.
Her first electroacupuncture treatment was on 8th April 2015. At this time she was head shaking and rubbing her nose at rest in the stable and field. Ridden exercise was not possible so she was scored as a Grade 3.
The day after treatment, Izzy was ridden without any sign of headshaking.
Over the next two weeks she was asymptomatic on all but three days when she was scored at Grade 1 ie still able to be ridden. Her second treatment was on 21st April (13 days later) when she scored Grade 2.
Izzy’s third treatment was on 12th May, an interval of almost 3 weeks. During this time she had 14 days at Grade 0, 3 days at Grade 0/1, I day at Grade 1 and towards the third treatment there was one day at Grade 2 and one at Grade 3.
Treatment 3 lasted until July 2nd – a period of 7 weeks and 2 days. 46 days were at Grade 0, one at Grade 0/1, two at Grade 1. Just prior to her 4th treatment, Izzy scored one day at Grade 3 and one at Grade 2.
The 4th treatment was given on July 2nd and to date (2nd September 2015) Izzy has not shaken her head – that is a period of seven weeks. She competed in dressage regional finals on 22nd July 2015.
Onions was 23 years old when treatment commenced. She is a Shetland pony, used for driving. She began headshaking late in June 2014 and quickly became Grade 3, ie unable to be driven and troubled by the condition at rest in the stable. Despite excellent management, Hypericum eye drops, carbamazepine, and three dry needling acupuncture treatments, she did not have any relief until the autumn.
In 2015 the headshaking recurred early in April, so like Izzy she was given the first electroacupuncture treatment on 8th April, when she scored Grade 2.
She was treated again 5 days later after 4 days at Grade 1 and one day at Grade 0 – so no symptoms in the field or stable but still bothered when being driven.
The third treatment was another week later following two days at Grade 0, three at Grade 1 and two not driven so not assessed.
Onions then went 22 days without further treatment. On 12 of these days she was not driven and therefore not graded – but showed no signs in the field. On the days she was exercised, 4 scored Grade 0, 6 were scored Grade 1 and just before the fourth treatment the condition worsened and she had 2 days at Grade 3 when she was not safe to drive.
Treatment 4 was given on the 13th May 2015. During the next 6 weeks Onions was not driven so often and scored mostly Grade 1’s with an occasional Grade 0 or Grade 2. At the beginning of June, however, her performance and comfort improved with a number of grade 0 days. Encouraged by this result Onions was given a 5th treatment on June 26th and has been asymptomatic to date – 2nd September 2015 – a period of nearly 10 weeks and ongoing.
I am extremely grateful to both Izzy and Onions for tolerating the treatment without complaint and to Hilary Parsons and Anne Radcliffe for allowing their horses to take part in this initial project. A big thank you goes to Kelly Donoghue for riding Izzy and patiently assisting with the project. The plan now is to recruit a larger number of horses and ponies and perform further studies in 2016. For more information please contact Sue via e-mail email@example.com
From Hilary Parsons, July 1st 2015: "Izzy has been fantastic no head shaking . . . . she has been working very hard, unheard of at this time of year. We are starting to become very excited with these results."
July 23rd after regional finals: "It is brilliant that she is even rideable at this time of year, let alone competing. That is down to you. Thank you so much"
Anne Radcliffe, 21st July 2015 "Dear Onions is still going really well and showing no signs of head shaking which is great news. It will be really great if we can get through the summer like this. It is all too good to be true. It really does seem the acupuncture has worked, I can't thank you enough, it really has changed her life and mine."
11th August 2015 "Dear Onions is still going brilliantly so much better than she has been for a long time. She just loves her work and is so enthusiastic. I still have the same stable regime, in by day and out by night. I still take her out with the mask and nose shield on. I am going to try and take her on a sponsored drive with Tripe if I can find one, as she hasn't left home for the last 18 months. It has made such a difference being able to take them out together not nearly so time consuming as driving singles, especially as I couldn't imagine that I would ever be driving a pair again. We have so much to thank you for."
23rd August 2015 "She is still going very well and enjoying her driving which is wonderful."
April 2016 – update on Izzy and Onions
For the remainder of 2015, Izzy remained asymptomatic and in work until 10th December, when her rider was suspicious the head shaking was about to recur. She was definitely showing signs when re-examined and treated on December 11th. Since then she has been asymptomatic and in March 2016 Izzy was selected as an individual for the British Dressage Intercounty Championships. Well done Kelly and Izzy!
Onions has not been treated since 26th June 2015 and has not been troubled by any clinical signs since.
More recently, 3 more horses and ponies have been treated. It became clear that the previously used method of scoring the head shaking was not adequate for these patients, which showed more variable signs. The new grading system used is below:
Head Shaking Grades
|Signs at rest in stable or field||Signs at Exercise|
An 8-year old, 18hh KWPN gelding used for Eventing was treated for the first time on August 21st, 2015. His clinical signs were shown mostly at exercise and progressed quickly from Grade 0 to Grade 3. Subsequent treatments took place on 27th August, 7th September and 17th November 2015. On each occasion he showed no signs the day after treatment. Following these 4 treatment sessions he remained asymptomatic until 4th April 2016 when he was treated again after a gap of 5 months.
A 14-year Eventing Pony, started head shaking July 2015. Signs were variable, but at times he was unrideable. Treatments were given on 24th November 2015, 7th December 2015, 28th December 2015, 11th January 2016, 1st March 2016 and 11th April 2016. Although this pony requires regular treatment, he has been able to continue competing at a high level.
"Google" a 5-year KWPN gelding. This young horse started head shaking in September 2015. Whilst some days he was asymptomatic, there were days when he was observed to suddenly gallop off in the field, flicking his head and striking his face with a forelimb or frantically rubbing his nose.
On the day he was first assessed there was light rain and wind. He became very distressed on the lunge with a high head carriage and recurrent, violent, vertical flicks of his head. When walking he constantly rubbed his nose on the ground and the head shaking persisted when he was brought into the stable for treatment.
He was treated on 9th March 2016 for the first time, and again on March 14th, March 22nd and 28th. At the time of writing on May 4th 2016 he has not shown any further signs and has been in regular work which was previously not possible.
From Lorraine and Tiah Wood: "We’re really, really pleased. It is looking like he has a happy future ahead of him and that is all credit to you."
Electroacupuncture is not a cure for headshaking, but it is proving to be an effective management tool that alleviates the pain and allows affected horses and ponies to continue their regular work. The treatment can be done at home and is well tolerated. Light sedation is necessary so withdrawal times must be considered with competition horses.
This work is continuing and more horses are now under treatment. Watch this space!