Q: I have a 12-year-old warmblood who will not tolerate a fly mask, which he badly needs to protect his eyes from insects and the desert sun. If I put on a mask, he swings his head continuously in a vertical, sweeping arc. As soon as I remove the fly mask, he stops. He has done this with every type of mask available. Once he kept swinging his head all day!

My veterinarian can find nothing wrong with my horse’s eyes, ears, head, teeth, etc. His only other vice is that he cannot be locked in a stall; he whirls and tries to get out. So instead, his stall door is always open, and he can roam at will in a two-acre outdoor jumping arena. Otherwise, he gives us no problems with shoeing, shots, grooming, worming, saddling, etc.

I know of no other horses who won’t accept a fly mask. Can anyone help me? Name withheld by request

A: I am glad your veterinarian evaluated your horse. It is very important to rule out any underlying medical causes for an unwanted behavior before proceeding with behavior modification.

Your horse seems to show signs of confinement frustration or claustrophobia, and he is showing irritation and aversive behavior to rid himself of the mask. You did not mention how your horse behaves in a narrow trailer or when you are placing a blanket on him. If his behavior is similar in any situation where he feels confined, we can assume this is the primary issue.

To get your horse comfortable wearing a fly mask I suggest the following techniques:

  • Desensitization (DS)—a gradual, step-by-step exposure where you never provoke the unwanted behavior.
  • Counter-conditioning (CC)—the preferred method of changing a horse’s emotional response to a specific trigger.

DS and CC are most successful when used together. With DS, you gradually reintroduce your horse to the fear-eliciting stimulus, in your case the fly mask. With CC, you reward and reinforce a positive, relaxed state. Your goal is to replace the unwanted emotional reaction—fear, anxiety and head tossing—with a more relaxed, comfortable response such as lowering his head and keeping it still.

DS and CC must be performed correctly to be effective, but fortunately, this is not difficult:

Start with your horse in a halter and lead rope in a safe place. Make sure he is relaxed, with his head low. Then introduce the mask by holding it far enough away that the sight of it doesn’t bother him. It could be a foot or an arm’s length away, partly behind your body, or held by a second person at a distance of several feet. Next, bring the mask a little bit closer to the horse. Take care not to move it suddenly or so close that he backs off, raises his head or exhibits a fear response. When you’ve done this perhaps two to five times, and your horse doesn’t react to the mask at that distance, move it another step closer.

Once he’s comfortable with the mask being close to him, you can touch him with it and rub it over his body like a big brush. When he accepts the mask touching his body, then start using it to pet his head. Repeat a couple of times.

Throughout all of this, watch your horse closely for signs that suggest fear or irritation (moving away, head tossing, stiffening of the body, faster breathing) or acceptance (calm manner, relaxed attitude, interested in something else). Offer small, tasty treats while your horse is standing relaxed with his head low. You want to reward him for remaining calm in the presence of the fly mask. Always make sure your horse is comfortable and accepting of the current step before proceeding to the next.

Once your horse can tolerate having the mask rubbed on his head, slowly hold it over one eye for a short period and remove it when your horse is quiet. Then gradually let the mask sit on the horse’s head without fastening it. Again, take it away when your horse is calm and reward him with a treat.

When your horse accepts wearing the mask over the eyes for a few minutes, start fastening the Velcro. You might find that the tightening is the real problem. If that is the case, then keep the straps very loose at first, and leave the mask on in his stall while he’s eating grain or his treat and being supervised. Gradually increase the periods of time your horse wears the mask, but keep him busy, doing some light ground work or longeing. Then he will be distracted by what he is doing, and you can reward him for other things, such as transitions over poles, while he is also wearing the mask.

Never punish the horse for a fear response, and be careful to avoid inadvertently rewarding negative behavior. Horses learn quickly from negative or removal reinforcement. If you take off the mask while the horse is tossing his head, you are rewarding that behavior.

Always remember that a calm environment and demeanor, gradual nonthreatening steps, and a rewarding association are the keys to undoing your horse’s aversion to the fly mask.

Jeannine Berger, DVM
University of California–Davis
Davis, California