Toxic fungus appears in Missouri pastures
The first two weeks of July are prime time for ergot to appear in common pasture grasses, said University of Missouri Extension forage specialist Craig Roberts.
Wet, cool weather, followed by heat and humidity, creates favorable conditions for the disease. “With the amount of moisture in the ground and in the plants, the state turns into an incubator when it gets hot,” Roberts said.
Ergot, a fungus, produces toxic alkaloid compounds. “It will be another ergot year,” said Tim Evans, toxicologist in the MU College of Veterinary Medicine. Ergot appeared in pockets of Missouri in 2013.
Callaway County residents Robert and Linda Schaefer reported ergot in fescue pastures on June 25. It was spotted by a USDA staff member who was making a farm visit.
They have cattle grazing on the pasture and needed know what to do. Roberts and Evans told them to cut the pasture to a 4-inch height and bale later. “This removes toxic seed heads and low quality stems,” he said. “It also stimulates regrowth, which we might see with this year’s rainfall.”
Roberts advises against feeding infected seed heads to livestock. If hay is made, producers should be aware that at least half of the alkaloid concentration remains, even if the hay is field cured and stored for more than a year.
Time is critical, Evans said, because ergot infestation can potentially kill cattle and, even, horses, especially when it hot and humid. The toxins constrict blood vessels, increase respiration rates, raise core body temperatures and limit blood supplies to the extremities of animals. Ergot poisoning sometimes is confused with fescue toxicosis, which is commonly referred to as “fescue foot” in the winter and “summer slump” during the hotter times of the year.
Evans said ergot poisoning can look like fescue toxicosis on steroids. Cattle poisoned by ergot, like those with “summer slump,” often have elevated body temperatures and seek relief in the shade or stand in water to cool off. Other symptoms can include overall malaise characterized by rapid breathing, decreased appetite and milk production.
However, ergot can also cause abortion in pregnant cows, possible sloughing of the switches of tails and tips of ears, even during the summer, severe lameness and potentially death.
Ergot bodies on seed heads look like mouse droppings. The ergot bodies are easily visible in the seed head of cereal grains such as barley, oats, wheat, triticale and rye as well as many common grasses such as timothy and tall fescue.
Ergot may give a slight black cast to an infected field. “Once you start to look for it, it’s really evident,” said Linda Schaefer.
Ergot also can be toxic to humans and other ruminants, llamas and alpacas, swine and, even, dogs.
For 100 years, MU Extension has engaged Missourians in relevant programs based on University of Missouri research. The year 2014 marks the centennial of the Smith-Lever Act, which formalized the Cooperative Agricultural Extension Service, a national network whose purpose is to extend university-based knowledge beyond the campus.