A cool, wet spring in many areas of the U.S. has farmers and ranchers on the lookout for ergot in cattle and livestock pastures, as infected small grains and grasses can cause death in animals.
Ergot, a fungal disease, can affect wild and cultivated grasses, as well as wheat, oats, barley and rye. The hard ergot bodies look like small rodent droppings and are easily visible in the seed head of cereal grains, as well as many common grasses such as timothy and tall fescue, according to Dan Undersander, University of Wisconsin-Extension forage agronomist.
The fungus only appears in seed heads and is present this year due to late pasture and hayfield harvesting because of wet conditions, Undersander said.
Infected grass crops should be harvested to remove fungus infected seedheads and destroyed, not fed to livestock or grazed. All infected hay should be destroyed and should not be used for animal bedding.
It might be possible to reduce ergot toxins by ammoniating the hay, but there is little published research on this approach, University of Missouri Extension Forage Agronomist Craig Roberts said. At least half of the alkaloid concentration produced by the ergot bodies would remain even if the hay were field-cured and stored more than a year.
Undersander said ergot's toxin can reduce blood flow and accumulate over time if small amounts are eaten regularly. It's poisonous to cattle and other ruminants, llamas and alpacas, horses, swine, dogs and humans.
In cattle, the first symptom of the alkaloid is lameness, two to four weeks after exposure, as a result of the reduced blood flow to extremities. The reduced blood flow will eventually lead to complete blockage of blood vessels with terminal necrosis of the extremities such as hooves and ears, Undersander explained.
According to MU, cattle may also seek relief in shade or stand in water. Other symptoms might include overall malaise, rapid breathing, sloughing of the switches of tails and tips of ears, abortion, and possible decreased milk production.
Ergot poisoning has been linked to human epidemics in the Middle Ages, MU said. The alkaloid toxins in ergot are chemically related to LSD, and some scientists suggest that bread made from infected rye may have played a role in the 17th-century witch trials in Salem, Mass., and even the French Revolution.