Could anyone give me some advice on the use of grazing muzzles; I have two mares, each with a different issue; my elderly (29 year old) standardbred colics if she is put out on spring pasture too suddenly, but I don't have control of that; my Morgan is just an easy keeper and she puts on way to much weight when she is out on the rich pasture at my barn; both girls are out during the day and in at night; I have been thinking about trying grazing muzzles for them this spring; I would love to hear from some of you who have experience with these.
I've used grazing muzzles for years. I use the Best Friend model, which stays on, doesn't require a halter, and stands up to quite a lot of abuse. I've had very good luck using them not only on pasture but on Cushingoid horses/ponies and equines with Metabolic Syndrome when kept on dry lots and fed hay. As I recall the studies done on grazing muzzles say roughly that intake is cut by 50% to 75% over time, and that's been my experience. Horses/ponies can and will eat hay through the muzzles, quite successfully, but the muzzles slow them down a LOT, so they're kept busy for much longer and take in far fewer calories.
Some horses will work quite hard to try to get the muzzles off, so you have to watch for that in the early days. Once they figure out how to eat/drink through them they usually give up and tolerate them very well.