Question: I put a grazing muzzle on my fat gelding. He is ridden multiple times a week, but is an easy keeper. He shares 8 acres of pasture with one other horse. Should I leave the grazing muzzle on all the time or give him an hour of freedom without the grazing muzzle each day?
Answer: We know from past research that a grazing muzzle reduces intake by 30% and that some horses can become very adept at grazing through a muzzle. As long as the horse can easily access water and can tolerate wearing the muzzle, we recommend leaving the muzzle on all day for an overweight horse with access to pasture. A 30% reduction is calories (or pasture) should result in weight loss. Research has also shown that horses with access to as little as 3 hours of pasture each day can consume a majority of their daily calories and can anticipate and adjust to the restricted grazing schedule.
Owners should track their horse’s bodyweight and body condition score each month. Reduce the amount of time the horse is muzzled if excessive bodyweight and body condition is lost. Conversely, if the horse starts to gain bodyweight (or is not losing bodyweight), it might be best to house the horse in a drylot and feed a reduced calorie hay diet (i.e. mature grass hay). The goal should be for the horse to lose weight slowly but steadily. If excessive bodyweight continues to plague the horse, we recommend working with an equine nutritionist and your veterinarian to identify additional solutions for weight loss.
This article is reprinted with permission from Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.