Watch for fescue toxicosis

Cattle on pasture at UT East Tennessee AgResearch and Education Center

Fescue toxicosis is still a problem for cattle producers in Tennessee and beyond during the summer months. Photo courtesy UTIA.

Fescue is the primary forage for cow-calf production in Tennessee and the upper Mid-South. It is the source of both pasture and hay, yet in spite of the contribution fescue makes to the cow-calf industry, the problem of fescue toxicosis still results in reduced cattle performance.

The greatest problem with fescue occurs during the summer months and extends into the fall. University of Tennessee Extension beef specialist Jim Neel refers to this period as the “summer slump.”

“Here in Tennessee, when the grass goes to seed, the endophyte concentration is the greatest,” Neel says. “Early grazing pressure in the spring and harvesting fescue for hay before it goes to seed will aid in reducing the concentration of the endophyte,” he recommends. Neel adds that producers should try to get fescue cut in the “boot stage” – that is while the grass flower is still in the sheath. Grazing pressure can also contribute to the reduced formation of seed heads.

Neel also reminds producers that throughout the summer they need to provide shade and water for the cattle. “The environmental temperature will be probably the hottest during the summer slump,” he says. “In addition, digestion of the forage also adds to the body temperature of the cattle.”

Another big source of the cattle’s elevated temperature is the toxic effect of the endophyte, Neel said. “Consider weaning and conditioning the calf crop for marketing. Generally, the gain of the calves is very poor due to the reduced forage availability and quality as well as milk production of the dams. However, if weaned and fed a concentrate ration, the calves will efficiently convert the feed to gain. “On-the-farm” field trials conducted here in Tennessee several years ago support these recommendations, he adds.

The cattle specialist says mature cows get along well on summer’s lower quality forage, and they gain both weight and body condition, which help with reproduction. Research done over five or more decades at Southeastern land-grant universities demonstrates that maintaining 30 percent clover in fescue stands improves the performance of the cattle.

Neel adds that there is no silver bullet that can replace management of fescue and cattle to reduce the effect of the endophyte. “
There are times in the annual production cycle of fescue that the grass quality is better and this can be capitalized on by appropriate cattle and forage management,” he said.

For more information about fescue toxicosis or beef cattle management, contact your
local county UT Extension agent or visit the UT Beef and Forage Center website

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the UT Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.



Dr. Jim Neel, UT Department of Animal Science, 865-974-3189,


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