If like many owners you have considered using a grazing muzzle, you may have been left wondering whether or not they really work. Two recent studies have set out to answer this very question!

horse forage

Study One:

The effect of wearing a grazing muzzle vs. not wearing a grazing muzzle on intakes of spring, summer and autumn pastures by ponies


• Grass intake was measured across 3 hours on 4 occasions in 4 ponies with and without a Shires grazing muzzle in spring, summer & autumn
• Grass intake was calculated using changes in body weight (BW), accounting for droppings & urine (which were collected in ‘nappies’) and natural weight loss due to the evaporation of water in the body


Key Results

• On average grazing muzzles reduced intake by 78% in spring, 77% in summer and 83% in autumn
• Without a muzzle, ponies consumed on average 0.51% BW in spring, 0.57% BW in summer & 0.8% BW in autumn

What does this mean?

• Across the seasons, muzzles reduced grass intake by approximately 80% on average and may therefore be an effective method of reducing grass intake throughout the year.

Shires Grazing Muzzle

Study Two:

Efficacy of wearing grazing muzzles for 10 hours per day on controlling bodyweight in pastured ponies



• 5 non-obese ponies were turned out for 23 hours per day either without a grazing muzzle (FREEGRAZE treatment) or with a grazing muzzle fitted for 10 out of the 23 hours per day (MUZZLE treatment) during a 6 week crossover study (ponies were divided into 2 groups and were exposed to both treatments)
• Ponies were weighed on alternate days at 8am and 6pm

Key Results


• 4 out 5 ponies gained significantly less weight during the MUZZLE treatment
• 2 ponies exhibited ‘pasture damaging’ behaviour whilst wearing a muzzle, digging holes of approximately 35cm in diameter with their forefeet
• 1 pony became resentful of wearing the muzzle during week three and lost weight
• 1 pony had to be removed from the study after gaining weight rapidly during the MUZZLE treatment (this pony did not therefore complete the FREEGRAZE treatment)

What does this mean?


• Using a grazing muzzle for 10 hours per day may be an effective weight management strategy for some but not all ponies living out at pasture
• Individual horses/ ponies should always be monitored closely for changes in body weight and behaviour

For more advice on how to use grazing muzzles safely call the SPILLERS Care-Line on 01908 226626

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