What is the purpose of using a twitch?

Veterinarians, Registered Veterinary Technicians (RVTs) and equine handlers use twitches often to aid in restraint and distraction during undesirable procedures.

How does applying one help a horse stay still/calm when being handled by an owner or veterinarian?

When the twitch is applied correctly to the horse’s upper lip, there is a short-term release of endorphins from the horse’s brain. This appears to be related to the stimulation of an acupuncture point for shock/respiratory centres on the horse’s muzzle – the mid-point, where the twitch is applied. The endorphins help keep the horse calm throughout the procedure. It is also another aid for the handler to have control of the horse.

Under what circumstances should/can they be used?

Twitches should be used for procedures that horses typically don’t like and cannot be sedated for. Many times, these procedures are done by a veterinarian such as nerve blocking, x-rays or joint injections. The transient calm and distraction that the twitch offers provides just enough time to perform the procedure and then the twitch is removed. Safety of the patient, veterinary staff and the equipment is paramount.

Under what circumstances shouldn’t they be used?

There are some horses that have had a bad experience with a twitch, and these horses may have a less than desirable reaction to the twitch in subsequent uses. The twitch should never be used when disciplining a horse, as this could result in negative associations when using the twitch for future procedures. A twitch should also not be used around the upper lip if there is any injury to the area.

Are there different types?

  • Rope twitch – rope is used around the horse’s upper lip, attached to a long pole.
  • Chain twitch – chain is used around the horse’s upper lip, attached to a long pole.
  • Metal clamp twitch – twitch is clamped onto horse’s upper lip and a cord is wrapped around the handles to keep it tight and secure.

What is the correct way to apply each type?

All twitches are applied by grabbing the upper lip of the horse, placing the rope/chain/clamp around the lip and tightening, either by twisting the poles or by clamping. The twitch should only be applied at the beginning of the procedure and removed as soon as the procedure is over.

Can they be harmful to the horse?

Yes, if applied incorrectly or kept on for too long. If the twitch is too loose, it is ineffective. If it is too tight, it is stressful/painful for the horse. Every horse is different, so there isn’t a prescribed time. It’s important to monitor the horse closely. It’s the handler’s job to ensure the horse is calm and handling the procedure well. If she feels the horse is growing agitated, she should call for a “pause and re-group.”

Are there consequences to applying one incorrectly?

If the twitch is applied incorrectly, it will result in inadequate restraint for the procedure, which could lead to injury to the horse, the person handling the horse or to the person performing the procedure. This also could lead to a negative association when using the twitch for future procedures. Plus, if the twitch is applied too tightly and/or for too long, there could be damage to the upper lip due to loss of circulation.

Are there any alternatives to using twitches?

  • Neck twitches, using a hand
  • Chemical restraint (i.e. a tranquilizer or a sedative)
  • Chain lead rope – lip chain, chain over the nose

Why is their use controversial to some people?

Those who don’t understand the scientific benefits of the twitch (releases endorphins) think that it is unnecessary and cruel to the horse.

Thank you to Carol Berkij, RVT, Kendra Holman, RVT and Lauren Wantje, RVT as well as Dr. Bri Henderson, BVMS MRCVS, of Cheltenham Veterinary Centre, for their contributions to this article.

Three Phases of a Twitched Horse

by Antonia J.Z. Henderson

According to equine behaviourist Sue McDonnell, a horse goes through three phases while being twitched.

During the “Distraction” phase, the first three to five minutes, the endorphin release has not yet been activated and the twitch has no analgesic (pain-killing) effect. During the “Analgesia” phase, the horse becomes heavy and relaxed, the eyes appear glazed, and the lower lip droops. This phase, where aversive interventions can be practiced, lasts for about 10 to 15 minutes, after which the endorphin output falls rapidly and the horse enters the “Blow” phase, so named because of the horse’s volatile and explosive behaviour. To ensure successful and non-traumatic twitch use, McDonnell recommends the following:

  • Twitch use should be limited to relatively short and mildly aversive procedures. Clipping the inside of a horse’s ear while using a twitch is appropriate; a full body clip courts disaster.
  • The twitch should be applied three to five minutes before the procedure begins, allowing sufficient time for the analgesia to take effect.
  • The twitch should be removed well before the rapid endorphin decline so as to avoid the explosive and dangerous Blow phase.
  • Horses should be habituated to the twitch, without an accompanying aversive procedure, to familiarize them with non-traumatic twitch use, and to learn each horse’s progression through the phases.
  • Contrary to the notion that the twitch will be more humane if not applied too tightly, the twitch needs to be sufficiently snug so as not to fall off and so that the analgesic effect is triggered. If the horse is not showing the heavy-headed, glassy look characteristic of the Analgesia phase, the twitch may be too loose to be effective.
  • Twitch use should always be positively reinforced with a food reward once the twitch is removed.

Horses that have always been correctly twitched do not become “wise” to the twitch, and do not mount a barrage of defensive behaviours. For horses that fear twitch use (because of a history of incorrect usage), repeated positive exposure without an intervening aversive procedure, in several brief sessions, and followed by positive reinforcement can be rehabilitative.