Few pieces of equipment are as inexpensive or easy to use as a grazing muzzle, but don't let its simplicity fool you. A muzzle can save a horse's life--reducing his risk of laminitis from overindulgence on rich pasture grass--or at least help keep him healthier by limiting his caloric intake.
When a horse wears one of these basket-like contraptions, he can breathe and drink normally but consumes only the blades of grass that poke through the muzzle's mesh straps. "Muzzles allow a horse all the benefits of turnout, from the exercise to the socialization to the fresh air, without the risks of consuming too much nutrient-rich grass," says Melinda Freckleton, DVM, a practitioner with Haymarket Veterinary Service in Haymarket, Va. Grazing can be further limited by covering the bottom hole with a thick cardboard disc.
"Any horse that doesn't need as much grass as is available to him" will benefit from a muzzle, says Freckleton. But this gear can be an especially important tool in managing horses with insulin resistance, Cushing's syndrome or those who are simply more susceptible to laminitis, particularly when grass is lush in early spring.
In fact, she says, experience has taught her that grazing muzzles are advisable for some horses well beyond spring. "We used to think that only new grass was the problem, so we'd put muzzles on when the new grass came in, then take them off when it got dry enough for the growth to slow. But as we learn more, we realize that it's not that easy to predict when the grass can be risky," says Freckleton. "I tell people that if they think maybe they should be muzzling, to go ahead and do it. And when you think the grass has died off enough to take it off, wait another week to be sure."
In general, she advises paying closer attention to your local climate than to the calendar. "The grass greens up all the time here in Virginia. It can be mid-November and we are still muzzling. You can't do it by the calendar alone. You have to make the call based on the current conditions." Freckleton adds that she leaves off muzzles when a new horse is introduced to the herd and in other situations when the social order may be temporarily disrupted: "You'd be taking away one of a horse's defenses if he gets into trouble."
As with any gear, fit is important (see illustrations in the PDF link below): To stay in place a muzzle needs to be snug, but if it's too tight it may rub. Nonetheless, warns Freckleton, an enterprising horse may try to get rid of even a well-fitted muzzle: "I've seen horses rolling on the ground to pull them over their heads, and a few learn to hook muzzles on fences and pull back to break them," she says. "One owner braided the horse's mane around the crownpiece of the muzzle and that solved the problem. You can get creative about securing them, but you still need to have a breakaway feature for safety."
For confirmed muzzle removers at risk of laminitis, a dry lot with no grass at all may be the only safe turnout option.
Click on the link below to see Melinda Freckleton, DVM, demonstrate how to check the fit of grazing muzzles on three horses: Dixie, Yogi and Jasmine.
(The article is in PDF format. If you have trouble viewing it, download the free Adobe Acrobat Reader program.)
This article originally appeared in EQUUS 380, May 2009.