Alfalfa Could Help Cattle Combat Heat and Fescue Toxicosis

By Blake Jackson

Beef producers in the Eastern United States lose an estimated $2 billion annually because of fescue toxicosis, according to University of Kentucky experts.

Heat stress adds another $370 million in losses. A new three-year research project is investigating whether alfalfa could help cattle better withstand these challenges.

The study, continuing through September 2028, brings together researchers from the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment, the USDA Agricultural Research Service’s Forage-Animal Production Research Unit and Auburn University.

Brittany Davis, Ph.D., leads the project, while UK researchers are handling much of the animal, plant and Extension work.

Ray Smith, Ph.D., a UK Department of Plant and Soil Sciences Extension professor and the university’s principal investigator, emphasized alfalfa’s long-standing importance as a livestock forage.

“Alfalfa, both today and over the last 3,000 years, has been the most important, most valuable forage crop in the world,” Smith said.

“It’s often called the Queen of the Forages, with corn silage being the King of the Forages. Alfalfa is known to be an outstanding crop for how much it can produce and how nutritious it is for animals.”

Researchers are particularly interested in flavonoids, naturally occurring compounds found in alfalfa that may improve blood circulation and help cattle cope with heat.

“We’re realizing that alfalfa has compounds that make it more than just a feed,” Smith said. “You can think of it as a nutraceutical or what we call a functional feed—one that supports animal health beyond simply meeting nutritional requirements.”

Tall fescue covers about 35 million acres in the Eastern U.S., and nearly 95% contains an endophytic fungus that produces ergot alkaloids. These compounds can restrict blood vessels and make it harder for cattle to regulate body temperature, eat, gain weight and reproduce.

“Fescue toxicosis and heat stress compound each other, especially here in the Southeast,” Smith said.

“Producers have been asking for practical solutions for a long time, and we think alfalfa has real potential.”

The research will identify effective alfalfa flavonoids and doses, examine varieties and growing conditions, test whole alfalfa in beef steers, and develop practical recommendations for producers.

“If we can show that alfalfa helps cattle stay cooler and healthier on fescue pastures, that gives forage producers a real incentive to expand acreage in this part of the country,” Smith said.

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