A twitch is a device that is used to restrain horses for various stressful situations, such as veterinary treatment. Although it may look and sound inhumane, a twitch calms the horse by releasing endorphins as pressure is applied on the twitch, not causing the horse any pain. It is usually made up of a stick-like handle loop of chain or rope on the end, or a metal ring with a rope loop which is wrapped around the upper lip of the horse and tightened. Another design, sometimes called a "humane" twitch, is a plier-like clamp that squeezes the lip with motion akin to that seen in a nutcracker. The aluminium screw twitch is yet another form of twitch.
How the twitch works
The upper lip of the horse is grasped and the loop of chain or rope is placed around it, then the handle of the twitch is twisted until the loop is firmly around the lip. A wooden handled twitch has the disadvantage that it requires a handler and the handle may injure the horse handler if the horse throws its head. Other twitches may be attached to the halter or headcollar. An emergency twitch can be improvised by placing a loop of leather or heavy cord around the nose and tightening it by twisting a stick around and around until it is tightened sufficiently.
The twitch is popularly believed to work by distracting the horse, but may act instead by triggering the release of endorphins from the horse's brain, producing a calming effect. The twitch is considered a humane method of restraint and is commonly used by horsemen and veterinarians to keep an animal still and quiet.
Misuses of the twitch
The twitch is not intended for use on any other part of the body of the horse other than the upper lip. It may cause permanent damage and behavioral issues (such as a head-shy horse when used on the ear) if it is used incorrectly. Additionally, if a twitch is left on for an extended period of time, its effects will diminish. This may be because the endorphin levels of the horse are eventually expended, or because the lip goes numb.
- Hayes FRCVS, Horace M., Veterinary Notes for Horse Owners, Stanley Paul, London, 1970
- The twitch in horses: a variant of acupuncture Retrieved 2010-8-15