Prolonged gestation; difficulty foaling; thick, retained placentas; and depressed milk production are a few of the more common clinical signs seen in mares grazing infected tall fescue. | Photo: University of Kentucky's College of Agriculture

Most horse breeders are aware of endophyte-infected tall fescue’s toxic effects on late-term pregnant mares. Prolonged gestation; difficulty foaling; thick, retained placentas; and depressed milk production are a few of the more common clinical signs seen in mares grazing infected tall fescue.

Property managers often test their pastures to evaluate the risk of fescue toxicity; however, testing isn’t all that simple, and how you test can produce drastically different results. Here are some things to remember when testing horse pastures for infected tall fescue