Written by Gary DiGiuseppe, OFN ContributorThe forage variety everyone knows as “Kentucky 31” fescue was discovered growing wild by Dr. E.N. Fergus – in Kentucky, in 1931, of course. From the University of Kentucky, it radiated out and was gradually adopted through much of the South and southern Corn Belt as the preeminent cool season perennial.
But it has its drawbacks, and among them are endophytes. The fungus Neotyphodium coenophialum dwells within the plants, and produces toxic alkaloids that can, in some cases, cause illness in livestock, including the condition known as “fescue foot.”
Dr. Shane Gadberry, University of Arkansas professor of animal science in the program areas of beef cattle nutrition and management, described the symptoms to Ozarks Farm & Neighbor. “You will find cattle that appear to be limping and have some mobility problems,” Gadberry said. “Some of the first inclinations a person might have is, ‘Maybe these cows are suffering from a foot rot’.” But upon closer inspection, the animal is not suffering from a bacterial infection.
Fescue foot can cripple cattle. “Toxins that are produced by the endophyte have vasoconstrictive properties,” Gadberry explained. “Fescue foot is a condition that occurs during cold weather; during cold weather the body wants to reduce blood flow to the extremities in an effort to keep warm. The additional vasoconstriction associated with those toxins can essentially shut off the blood flow to extremities, and so a condition with fescue foot is actually having the hoof slough off. You can also lose tails, and tips of ears.”
Although there are drugs that dilate the blood vessels, there is no specific pharmaceutical treatment for fescue foot. Gadberry said the best short-term treatment for cattle suffering from the malady is to remove them from the infected fescue. The demonstration herd at the University of Arkansas Livestock and Forestry Branch Station at Batesville had a severe outbreak of fescue foot this year, and was taken off the fescue for 30 days.
But Gadberry said a promising recent development has been fescue containing “friendly” endophytes.
“These are endophyte-infected fescues that produce some toxins,” he said, “but they do not produce the toxins that we most associate with the Kentucky 31 infected fescues.” Stocker calves have achieved better weight gains on the “friendly” fescue, and researchers are working with it at Batesville. “But because it’s expensive to convert from a toxic field to a non-toxic field,” said Gadberry, “they’re taking a stepwise approach” for instance, they’ll plant 25 percent of a stand in non-toxic varieties, and strategically graze it during the year.
If fescue toxicity poses an extreme problem, whether ranchers need to replace the stand should be considered on a case-by-case basis. Gadberry noted many Ozarks farms may have other cool-season forages mixed in with the Kentucky 31, or warm-season grasses. Although fescue foot may force operators to sell cattle, toxic forages have a much greater impact on general performance. “We know that the calves have much lower weaning rates,” he said “We know that the cow herd will have lower reproductive rates. So, that’s more of the justification for replacing a toxic fescue stand with a friendly endophyte-type stand.”
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