Grazing muzzles allow horses to experience the benefits of pasture turnout (exercise, socialization with herd members and the natural act of grazing) while restricting grass intake. Grazing muzzles come in several different styles but there are some that are designed to be attached to a halter, to be used without a halter or have one or several small holes that limit the size of a bite of grass that a horse/pony can take.
What Impact do Grazing Muzzles have on Grass Intake?
Depending on which research study you reference, the amount of grass intake is decreased with the use of a grazing muzzle can vary from 30 to 83 percent. The variability in the reduction of grass intake is likely a function of a few variables:
- The style of the grazing muzzle
- Length of grass at the time of the study
- Individual animal variation
There are several grazing muzzles available. One style of grazing muzzle only has a single opening; these will be more restrictive. Other styles of grazing muzzles have multiple openings and will allow for more grass to be consumed in each bite, and are, therefore, less restrictive.
Very short grass won’t protrude far enough into the muzzle and limits the “bite size” that a horse can take. Grass that is too long will lie over instead of protruding into the muzzle, making it difficult for the horse to access. (You will find differences in individual animal variation in any study that measures voluntary intake.) Simply put, some horses are more food-motivated than others. Often, the type of horse that is required to wear a grazing muzzle is highly food-motivated; however, some horses will find wearing a grazing muzzle more frustrating than others. Most horses adapt readily to grazing muzzles, even with some initial frustration; however, horses should be monitored to ensure they don’t give up on grazing due to annoyance with the muzzle.
Can my Horse Wear a Grazing Muzzle Part-Time on Pasture?
Horses that wear grazing muzzles only part of the day often do not experience a significant reduction in total pasture intake. This is because horses tend to adjust their behavior when they are restricted. During the time they are not wearing the muzzle, they may increase their grazing to compensate.
However, horses can still benefit from having part of the day without a grazing muzzle. During that time, it is recommended that they be kept in a stall or dry lot to prevent unrestricted pasture access.
What Horses Benefit from Grazing Muzzles?
The use of grazing muzzles is primarily recommended for horses that are overweight or have underlying health conditions that require sugar and starch (non-structural carbohydrates; NSC) intake to be limited.
A food-motivated horse on pasture can consume a significant amount of calories from grass in a relatively short amount of time. Grazing muzzles allow overweight or easy-keeping horses to spend time on pasture while restricting intake. Forage, hay or pasture represents the largest source of calories in the diet of the easy keeper; therefore, grazing muzzles can be a valuable tool to manage body condition.
Some underlying health conditions, including equine metabolic syndrome or PSSM Type 1, require limited NSC intake. By decreasing the amount of grass consumed, NSC intake will also be decreased. This does not guarantee that NSC intake will be low enough for a horse with metabolic conditions because pasture NSC fluctuates depending on growing conditions, particularly during the spring. Grazing muzzles may allow pasture time for some NSC-sensitive horses, but this must be evaluated on an individual basis.
Pasture Management
As previously discussed, the length of the grass is an important factor to consider when using grazing muzzles. The appropriate length is somewhat dependent on the variety of grass, but, in general, grass should be kept shorter in order to allow horses in grazing muzzles to eat without difficulty.
Special Considerations for Using Grazing Muzzles
In general, grazing muzzles are an easy-to-use and effective tool; however, there are some special considerations to ensure horse welfare.
- Ensure that grazing muzzles fit and don’t cause rubs on the face or muzzle.
- Utilize a breakaway-style halter for safety (if using a muzzle attachment).
- Limit grazing muzzle use to 12 hours per day or less.
- Confirm that grazing muzzles are compatible with water sources—some drinking post-style waterers have too small a circumference for grazing muzzles.
- Introduce muzzles in a positive manner, particularly for horses that are head shy.
- Monitor horse behavior and level of frustration with the muzzle.
- Monitor body condition score (BCS). If excess weight is lost, supplemental hay should be provided.
Grazing muzzles can be a valuable tool to allow horses to spend time on pasture while limiting intake; however, this is just one component in developing an overall feeding plan for the overweight or NSC-sensitive horse. Remember that your vet and nutritional experts are available for you and your horse to help you with a personalized feeding plan.
This educational blog was used with permission from Tribute Equine Nutrition.
