Careful management of endophyte-infected tall fescue can reduce losses from fescue toxicosis, says Craig Roberts, University of Missouri Extension forage specialist.

Missouri beef producers lose $160 million a year from poor-gaining calves and open cows grazing infected fescue, but most don’t see the loss, says Roberts.

“Many producers say, ‘My cows don’t have fescue foot, so I don’t have a problem with infected fescue,’ ” he says. “They don’t notice the loss of a half a pound of gain per day on their calves. Even a small beef cow herd can lose $3,000 per year to fescue toxicosis.”

Most tall fescue in the state is infected with the endophyte fungus that produces alkaloids toxic to grazing livestock. The good news is that the endophyte makes fescue hardy and resistant to drought and insects, so the grass can survive where other grasses fail.

“Fescue is our most widely used forage in Missouri,” says Roberts. “Tall fescue without endophyte toxin grows forage equal in quality to orchardgrass or bromegrass.”

Most forages, such as alfalfa, are managed for high yield and quality, but infected tall fescue must be managed to control the toxins. For example, good grazing management prevents tall fescue from setting seed.

“The seed heads have the highest concentration of the endophyte,” Roberts points out.

Alkaloids reduce forage intake and add to heat and cold stress. Cattle grazing fescue spend less time grazing and more time under shade or in ponds keeping cool. Also, those on fescue are more likely to retain their winter hair coats.

Newer, novel-endophyte fescue varieties have an endophyte but it doesn’t produce toxin. However, killing an infected fescue pasture and planting new grass takes time and money.

“One attempt to kill it won’t work,” says Roberts. “It takes spray, smother, spray.”

The standing grass is sprayed with herbicide, then an annual grass is planted into the dead fescue to provide forage. That crop smothers volunteer fescue plants that emerge and tillers that escape the first spray. After the annual is grazed or harvested the pasture is sprayed again before re-seeding.

Pastures to be seeded with new fescue next spring should be treated this fall and planted to a winter annual, such as wheat or rye. However, Roberts prefers to start the cycle in spring, using a forage sorghum or millet for summer grazing. Fall-seeded fescue has less competition with weeds.

“If you have grazing dairy cows or stocker beef calves, then replacement with a novel-endophyte fescue should be considered,” says Roberts. “For a beef cow-calf operation, careful management of the infected fescue might work.

“Adding legumes to fescue pastures dilutes the effect of the endophyte toxin,” he adds. “However, you never recover gains lost to the endophyte.”

Roberts will teach management of fescue pastures during the state grazing school at the university’s Forage Systems Research Center, Sept. 14-16. For details, visit