At last research has been carried out into the hotly debated practice of twitching horses. Whilst many horse owners already think that it is cruel to twitch the ears of a horse, lip twitching is more widely accepted. Hopefully this research will lead to an advancement in horse welfare...
The study recorded the response of 12 geldings divided into two groups; one group receiving a lip twitch and the other an ear twitch. Each horse was monitored for heart rate (HR), heart rate variability (HRV) and salivary cortisol levels.
The lip twitch which is the most commonly used form of twitching was shown to significantly decrease HR and HRV for the first 5 minutes, whilst also reducing salivary cortisol levels. However, when the lip twitch was left on for more than 5 minutes, the HR increased and HRV decreased. They also noted that the horses didn't seem to indicate any long term behavioural reaction to having been twitched in this way.
'Initially, the lip twitch increases parasympathetic nervous system activity, reduces stress levels, and has no effect on a horse's behaviour. This suggests that it subdues through a calming, probably analgesic effect. However, after the first five minutes of application, the lip twitch appears to significantly raise sympathetic tone, which raises questions about its suitability for periods longer than just a few minutes.'
Ear twitching on the other hand significantly raised HR, decreased HRV, and also increased cortisol levels, indicating that this method is highly stressful for horses and they are immobilised as a result of fear and/or pain. And not surprisingly 4 out of the 6 horses who had been ear twitched did not want to have their ear touched even four weeks later.
The researchers concluded that the ear twitch 'significantly raises sympathetic nervous system activity and stress levels and makes horses harder to handle both directly after application of the twitch and over time.'
From these findings they advise that ear twitching should not be used on horses and lip twitches should only be applied for a few minutes. If a horse needs to be subdued for a longer period, then a vet should sedate the horse instead.