Using the Twitch Properly

Q. I attended a short course on horse behavior at New Bolton Center where you explained how a twitch works and your recommendations for how to use it most effectively. It seemed to make so much sense why sometimes it works and sometimes it doesn't, and especially why horses can get to hate the twitch. Can you describe that in your column in The Horse magazine so I can show my employees and refer friends to their web site? I think it would be helpful if you could show the timeline for the endorphins that are released when the twitch is used. Also, please go over the part about how to fix a horse that is difficult or impossible to twitch.



A. Thanks for remembering. I looked over my presentation and will try to summarize it. I find it easier to demonstrate using a twitch than to describe in words, but here goes.

How does a twitch work?

The twitch works in three ways; it's important to understand how and when each applies. The figure above right schematically depicts some important features of how the twitch works. This is based on research we did here in the Behavior Lab at New Bolton Center more than 10 years ago. The first way a twitch works is by providing some minor physical restraint. The twitch, whether the pliers type (called a humane twitch) or the rope and pole type (often called a rope or chain twitch because of the loop that is twisted around the fleshy part of the nose), holds the head from moving as much. Some horses can be held in place by a twitch, but any horse that tries can easily break away from the restraint.

Second, the twitch provides some discomfort, especially when first applied. This discomfort, like a skin grasp, usually distracts the horse from minor manipulation or discomfort elsewhere.

And third, after some time in place, the twitch causes release of endorphins. These are chemicals released by the body that are naturally analgesic (pain-killing). So in this manner, the pressure of the twitch on the nose probably works like acupuncture or acupressure to release endorphins. Or just as likely, the endorphins are released because the twitch causes pain, and any time the body experiences pain, endorphins are released. It's nice to think of it as acupressure, but science just doesn't know yet.

So referring again to the figure, when a twitch is first applied, it is providing only the minor physical restraint and the mildly painful distraction. These two aspects will work for some horses for some procedures. You often see the handler rush to get a twitch on just before the procedure is about to begin, then rush through the procedure, then get the twitch off as quickly as possible. If it is on for only a minute or two, all that the horse has experienced, and all that it will remember about the twitch, is that it was mildly painful. It varies among horses, but the endorphins are not released until about three to five minutes of having the twitch in place. So the horse that gets a quick on-and-off use of the twitch never gets a chance to feel the "high" and pain relief of the endorphins.

For many horses, there is a struggle during uncomfortable procedures, and they end up slipping off the twitch, again and again. In such cases, as the struggle continues during the session, handlers understandably become frustrated and each repeated application of the twitch tends to be quicker and rougher. These horses have the experience that teaches them to escape and avoid the twitch. "I feel pain at my nose and elsewhere (wherever the procedure is being done), I struggle, the pain in my nose goes away, and they stop hurting me."

So one way to think of the full effectiveness of the twitch is that, like a tranquilizer or pain medication, it takes some time to work. And waiting for the natural analgesia to work, and finishing up while it is still working, is perhaps the most important concept in effective use. I remind vets that they wouldn't think of injecting an analgesic or tranquilizer and trying to complete the procedure within the first minute. Rather, they would wait for the drug to take effect. They would not continue with an uncomfortable procedure after the medication had worn off. The twitch is the same.


  • Approach and apply the twitch in a calm, confident, non-confrontational manner;
  • Apply the twitch in an efficient, unhurried manner;
  • Maintain appropriate tension--not too tight, not too loose; and
  • Monitor response/respect limits of analgesia. Don't start a procedure until you see signs of analgesia (such as the horse beginning to hang its head or become listless), and stop and remove the twitch while they are still present. Stopping while signs of effectiveness are still present will avoid leaving the horse with a bad memory of the twitch.


  • Employ rough handling and demeanor;
  • Add punishment (shouting, rough handling, extreme pain) during twitch application;
  • Lead by the twitch, which can be especially uncomfortable for the horse; and
  • Contact teeth and gums with the twitch; this can be especially and unnecessarily painful.

For the wooden-handled models with a loop, a rope is most always better than a chain. The chain is preferred by some because it gets a bite and is less likely to slip, but it can very easily damage the tissues.

Other Tips

It is helpful to practice the twitch with your horse before it is really needed, so that you can take your time and get to know your horse's individual pattern of twitch response before there is an emergency. How tight is just tight enough for this horse? How long does this horse take to become drowsy from the twitch? How long does that analgesia last? You can share this with your veterinarian.

If the procedure is almost done, and you think your horse is about to lose it, you can stop while the twitch is still having some positive effect and take a short break. For most horses, only a few minutes off the twitch restores their ability to have another fairly good rise in endorphins when the twitch is re-applied.

Rehabilitating an Escaper

Set aside a special time for re-training when you're not going to do a procedure. Just start over and go slowly, step-by-step. Reinforce increments of compliance with a food treat, massage of a favorite spot, or whatever makes your horse happy. Once it is applied, try to keep it on long enough for endorphins to be released. Be sure to follow the recommendations for gaining and maintaining compliance listed above.

If a horse has learned to slip the twitch, try to break that avoidance cycle. This requires some skill with the twitch, so you might need to see a behavior specialist at least at first. Remember, the horse has been taught by us to hate the twitch and has been reinforced for escaping it; don't attribute undesirable complex motives to him.

About the Author

Sue McDonnell, PhD, Certified AAB

Sue M. McDonnell, PhD, is a certified applied animal behaviorist and the founding head of the equine behavior program at the University of Pennsylvania's School of Veterinary Medicine. She is also the author of numerous books and articles about horse behavior and management.

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