A fungus that can kill horses and cattle is rampant in Missouri’s pastureland this summer — and has already felled at least four animals.
The fungus, called ergot, appears in grains and grasses when weather conditions are favorable, as they have been this year. The fungus is so widespread that state authorities are warning animal owners to be especially vigilant and to move animals to non-infected fields.
“It’s very severe this year, and I want producers to be on the lookout for it,” said Craig Roberts, a professor of plant science with the University of Missouri Extension and the state’s forage specialist. “I’ve seen it in every field and in every grass species.”
Ergot thrives when springs are cool and summers are hot, as has been the case this year. It typically infects grains, including wheat, oats and barley, but can affect grasses and pastureland, including hay fields.
“It can be fatal,” said Tim Evans, a veterinary toxicologist with the University of Missouri’s College of Veterinary Medicine. “I expect this year, we’re going to see problems.”
Evans said he was called to a farm in northeastern Missouri last week to help a local veterinarian identify what killed four cows in a 20-cow herd, which had been grazing on a pasture of fescue.
“I could see as I was driving onto the premises that the fescue was ergotized,” he said. “Since then I’ve seen quite a number of fields with ergot in it. I’ve talked to my colleagues in Iowa, and they’re seeing the same thing up there.”
The fungus is not only potentially fatal but can cause fertility problems and decreased appetite — a problem for the state’s cattle breeding industry, the third largest in the country. The cattle operations here feed young cattle up to a certain weight before shipping them to feedlots for finishing.
Dairy cows also can suffer from loss of production, and horses and llamas also are susceptible.
Ergot compounds cause arteries to constrict, causing labored breathing, raising body temperatures and restricting blood supplies to extremities.
Ergot looks like small rodent droppings in the seed heads of plants, and it can be easily seen in cereal grains and common grasses, including fescue.
Early mowing of pastureland usually limits the growth of ergot, but this year, because of the wet weather, producers weren’t able to mow and bale their fields, allowing the fungus to settle into seed heads.
The toxins in ergot are chemically related to LSD and have been linked to deadly epidemics in the Middle Ages, when it was known as St. Anthony’s Fire. Some historians believe that the symptoms of ergotism in people — scratching, convulsions and hallucinations — were behind the “bewitchment” that triggered the Salem Witch Trials. The poisoning in humans is usually linked to infected rye, which was grown in abundance in that region.
It commonly is seen in wheat, but the U.S. Department of Agriculture requires inspections and testing that limit its presence.