Grazing Muzzles

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 broadly are designed to be attached to a halter and have one or several small holes that limit the size of a bite of grass that a horse can take. 
   
What Impact Do Grazing Muzzles Have on Grass Intake? 

The amount that grass intake is decreased with use of a grazing muzzle has varied from 30% to 83%, depending on which research study is referenced. The variability in the reduction of grass intake is likely a function of several variables. 

  • the style of grazing muzzle
  • length of the grass at the time of the study
  • individual animal variation

There are a number of 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. 

Grass that is very short won’t protrude far enough into the muzzle and limits the “bite size” that a horse is able to take. Grass that is too long will lay 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 their grazing muzzle. 

Can My Horse Wear a Grazing Muzzle Part-Time On Pasture? 

Horses who wear muzzles part-time generally do not have a reduction in total pasture intake. This is because horses will alter their behavior when experiencing part-time restriction. During the times that horses are not wearing a muzzle on pasture, they will increase their intake. 

However, horses do benefit from spending part of the day without wearing a grazing muzzle. Confining them to a stall or dry lot during this time is recommended. 

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 be limited. 

A food motivated horse on pasture can consume a significant number 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. 

A number of underlying health conditions, including equine metabolic syndrome and 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 very effective tool; however, there are a couple special considerations to ensure horse welfare. 

  • Ensure that grazing muzzles fit and don’t cause rubs on the face or muzzle
  • Utilize a break away style halter for safety 
  • 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. As always, our team is here for you and your horses and we would love to help you with a personalized feeding plan. Contact us here!
 

NICOLE RAMBO, PH.D.