Horse owners utilize many management practices to limit calorie intake for obese horses, including restricting pasture access via a grazing muzzle. However, research has shown that horses often increase pasture intake when returned to an unrestricted situation. Drastic changes in grain intake are known to cause digestive upsets, particularly in the hindgut, so researchers set out to determine if drastic changes in pasture intake yielded similar results.

The research team, led by Paul D. Siciliano, PhD, associate professor in the North Carolina State University Department of Animal Science, separated six mature light horse geldings of similar weight and body condition into two groups.

A control group had access to pasture continuously while a restricted group wore a grazing muzzle for 12 hours per day. After seven days, the groups switched protocol for an additional seven days. On day seven of each period, blood and feces were collected at intervals for plasma protein and fecal pH determination. In addition, pasture samples were obtained for chemical composition analysis.

After reviewing their results, the team found that hindgut health in horses with restricted access to pasture by grazing muzzle for 12 hours per day was not compromised compared to horses with unrestricted access to pasture