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The interaction of grazing muzzle use and grass species on forage intake of horses

Krishona Martinson, Emily Glunk, Craig Sheaffer and Marcia Hathaway

Description of the problem

Obesity has reached alarming levels in the horse population. Recent research has shown that approximately 20% of the horse population is considered obese with a body condition score of ≥. Obese horses are at higher risk for diseases, including laminitis and metabolic syndromes, are inefficient at thermo-regulation, have specialized nutritional needs, have poor reproductive efficiencies, and experience reduced performance. In an attempt to alleviate this problem, horse owners have sought to restrict forage intake by a number of methods, including decreasing the amount of time while on pasture. However, restricted grazing is not always effective. Researchers found that horses were able to increase their dry matter intake rates with restricted turnout time. Therefore, many horse owners are in need of simple and affordable management strategies that restrict pasture intake while maintaining a horse's natural environment. In recent years, the use of a grazing muzzle has gained popularity because its use limits forage intake while still allowing for turn-out, exercise, and socialization in a pasture setting. However, horses are known to be selective grazers, and researcher have found that horses preferred timothy and Kentucky bluegrass, while exhibiting less preference for meadow bromegrass and orchardgrass. Researchers have also observed that forage growth type (or morphology) affected grazing livestock's' forage preference. However, it is unknown if preference and grass morphology impact the effectiveness of a grazing muzzle.


Determine the effectiveness of grazing muzzle use at reducing forage intake when horses grazed grasses with different morphology.

Accomplishments and results

The use of grazing muzzles was effective in decreasing initial herbage mass consumed by an average of 30%, regardless of forage specie grazed. During the second year of the study, there was an effect of species on percent initial herbage mass consumed. Horses consumed more Kentucky bluegrass compared to reed canarygrass both with and without the use of a grazing muzzle, providing further evidence that horse prefer Kentucky bluegrass over reed canarygrass.

Benefits to the equine industry

The use of a grazing muzzle reduces a horse's pasture intake by approximately 30%, regardless of grass species. Using a grazing muzzle appears to be an effective management strategy for restricting forage intakes of grazing horses, and may offer a simple and affordable solution for combating equine obesity. These results will be useful in helping horse owners, veterinarians and nutritionists develop more accurate rations for muzzled horses on pasture.

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