Q: What is the relationship between grazing on pasture and laminitis?
A: One of the factors that can predispose horses to laminitis is the rapid intake of nonstructural carbohydrates (sugars and starches). Intake of starches or fructans (a sugar) stored in pasture can cause laminitis. Fructans are the primary reserve carbohydrate stored in cool season grasses like fescue and bluegrass. Grazing management is important for horses predisposed to laminitis (often ponies and overweight horses). This includes limiting grazing during the times of day when fructans are at their highest level a in grasses.
Generally, horses predisposed to laminitis should graze in the evening and over night and be inside or in dry lots during daylight hours. Grazing should also be limited during times of environmental stress on plants such as drought or cool temperatures. Rotational grazing is recommended where regrowth is limited to 4 to 6". It is important not to over graze pastures as the lowest stems often contain the highest amount of sugar. Avoid grazing on pastures with lots of seed heads as they also contain high amounts of sugar.
By Stephanie Valberg, DVM, PhD, University of Minnesota