Muzzle Adjustments May Prevent Teeth Damage

by: Joyce Harman, DVM

Harmany Equine Clinic
Sheila Whaley

Muzzles are often accused of damaging the horse’s front teeth. This can be true, but it’s important to put it in the correct context. A grazing muzzle prevents a horse from overeating grass, which can save her life, or at least save the horse a bad case of laminitis and the owner thousands of dollars in veterinarian bills. However, as with everything in life, a bit of knowledge and common sense will make wearing a muzzle much less damaging. Horses that crib or run their teeth on bars in the stall often wear their teeth much more than what occurs with a muzzle, yet muzzles get the blame for tooth damage.

Because the muzzle restricts the amount the horse can put in her mouth at one time, some horses become frustrated. This can cause stress, leading to increases in ulcers and can increase Insulin Resistance (IR) (i.e., well-documented in human medicine—stress not muzzles). If your horse shows signs of being uncomfortable after eating, has a poor coat or any digestive issues, it might be useful to put her on some herbs or probiotics for ulcers.

Another way a horse displays stress is by pushing harder against the ground trying to eat to more. These horses are the ones most likely to wear their teeth. This is especially true if an adjustable muzzle, like the Harmany Muzzle, is used. It is important to adjust the number of holes available to the individual horse depending on her size or the amount of grass in the field. Other muzzles do not have the ability to change the size or number of holes, so if the grass is sparse, the horse will try harder to eat enough.

Muzzle material also plays a role in the amount of teeth wear. The traditional rubber sounds soft on the teeth; however, remember, the horse is pushing it against the ground as she grazes. The ground is hard. Rubber does give a little and wears easily. I see many rubber muzzles where the hole is two to three times larger than it’s supposed to be. At that point, there is no restriction in grass intake.

Plastic muzzles are made from variable hardness plastics. The Harmany Muzzle is in between very hard and soft. If the horses push hard against the ground, they will wear it out eventually and will wear their teeth some. Hard plastic muzzles will wear the teeth faster and may not wear out as easily. However, if the horse grazes quietly and accepts the muzzle without putting too much pressure on it, even the harder plastic ones will work fine. Soft plastic may just wear out rapidly unless the horse is easy on it.

So, when selecting a muzzle or complaining to the manufacturer about wear, observe if your horse is grazing with gusto and lots of pressure, or just moving quietly across the grass eating. Also, be sure there is enough of an opening so the horse can get enough grass to satisfy herself without getting too much. In the Harmany Muzzle, the single hole in the center is not enough for most horses but having too many holes across the bottom like some muzzles, may not be restrictive enough.

Dr. Joyce Harman owns Harmany Equine Clinic, Ltd., a holistic veterinary practice in Washington, Virginia. Visit

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