Parson, Kansas — Most beef producers never see the loss created by toxic tall fescue pastures.

“Many producers say, ‘My cows don’t have fescue foot, so I don’t have a problem with infected fescue,’” said Craig Roberts, University of Missouri Extension forage specialist. “They don’t notice the loss of a half a pound of gain per day on their calves.”

But, Missouri beef producers lose $160 million a year from poor-gaining calves and from the number of open cows caused by grazing fescue, Roberts told field day visitors at the MU Forage Systems Research Center (FSRC), Linneus. “Even a small beef cow herd can lose $3,000 per year to fescue toxicosis.”

Most tall fescue in Missouri is infected with an endophyte fungus that produces alkaloids that are toxic to grazing livestock. The good news is that endophyte makes fescue hardy and resistant to drought and insects. Fescue can survive where other grasses fail.

“Fescue is our most widely used forage in Missouri," Roberts said. “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 high quality, Roberts said. However, infected tall fescue must be managed to control the toxins.

“The seed heads have the highest concentration of the endophyte,” Roberts said. Good grazing management prevents tall fescue from setting seed.

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 coat. “The calves look like brown fuzz balls,” Roberts said.

New varieties of fescue contain a novel endophyte that does not produce toxin. The new grasses have an endophyte, but not the alkaloid toxins. One such variety is MaxQ tall fescue.

Three new novel-endophyte fescues are in development, Roberts said. They should be available for planting next year.

However, killing an infected fescue pasture and planting new grass takes time and money. “One attempt to kill it won’t work,” Roberts said. “It takes spray, smother, spray.”

The standing grass is sprayed with herbicide. An annual grass crop 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 would be treated this fall and planted to a winter annual, such as wheat or rye. However the specialists prefer to start the cycle in the 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,” Roberts said. “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,” Roberts said. “However, you never recover gains lost to the endophyte.”

Pastures with toxic fescue produce toxic hay, Roberts said. However, over time, the endophyte toxins degrade causing less damage to livestock.

“Half is gone in half a year. That’s a rule of thumb for stored infected-fescue bales,” Roberts said. “Summer hay fed in January will be much less toxic.”

Endophyte toxins begin degrading as soon as hay is mowed. Sunshine on curing hay cuts toxins by one third.

The first step is recognizing the problem, and then managing the grazing to reduce the losses.

Roberts will teach management of fescue pastures at the State Grazing School at FSRC, September 14-16. Enrollment details for the fee school and driving directions to the Center are at aes.missouri.edu/fsrc/.