Wet and cool weather, followed by heat and humidity, creates favorable conditions for ergot, a toxic fungus found once again in Missouri hayfields and pastures.

The first few weeks of July are prime time for the disease to show up, warns University of Missouri (MU) Extension forage specialist Craig Roberts.

Ergot infestations can potentially kill cattle and even horses, especially when it is hot and humid, notes Tim Evans, MU toxicologist. The toxins constrict blood vessels, increase respiration rates, raise core body temperatures and limit blood supplies to the extremities of animals. Ergot also can cause abortions in pregnant cows, he says.

Ergot bodies, which look like mouse droppings, first appeared in parts of Missouri in 2013, adds Evans. They are easily visible in the seed head of cereal grains such as barley, oats, wheat, triticale and rye as well as in many common grasses, such as timothy and tall fescue.

Producers in Missouri’s Callaway County are already contending with ergot in fescue pastures. Roberts and Evans suggested that they cut infected pastures to 4” heights to remove toxic seed heads and low-quality stems, then bale later.

Infected seed heads should not be fed to livestock, Roberts adds. At least half of the alkaloid concentration remains when hay is made, even if the hay is field-cured and stored for more than a year.