Submitted to: Cow Country News
Publication Type: Popular Publication
Publication Acceptance Date: 6/25/2015
Publication Date: 7/1/2015
Citation: Aiken, G.E. 2015. From the Lab Bench: Should you plant a non-toxic endophyte tall fescue? Cow Country News. p. 26.
Interpretive Summary: Tall fescue is a cool-season perennial grass that is utilized for forage on approximately 35 million acres of the USA; however, toxic ergot alkaloids produced by the endophyte that infects most plants of tall fescue can induce a toxicosis in cattle that costs the U.S. cattle industry approximately 1 billion dollars per year in lost production. Novel endophyte-infected tall fescues are now commercially available that do not produce the toxic ergot alkaloids. Although the novel endophyte-infected fescue are persistent, a column was written to make recommendations to minimize the effects of overgrazing and reduce the risk of losing stands: 1) maintain good soil fertility, 2) less heat stress on grazing cattle will increase fescue consumption such that stocking rates should be reduced in the late spring and summer, and 3) use a rotational stocking system. Cattlemen interested in alleviating fescue toxicosis can replace toxic endophyte-infected tall fescue with non-toxic endophyte-infected tall fescue, but management inputs will be required to maintain these the non-toxic tall fescues.
Technical Abstract: A column was written to discuss planting novel endophyte tall fescue for alleviating fescue toxicosis. Endophyte-free tall fescue cultivars can be grazed as a non-toxic alternative, but it maust be understood that it is the endophyte, through production of alkaloids other than ergot alkaloids, that makes the fescue plant hardy and productive. Non-toxic endophyte strains have been developed and are commercially available that serve as the only management tool in alleviating fescue toxicosis for cattle grazing tall fescue. To establish novel endophyte tall fescue without contamination from volunteered toxic tall fescue you should use the spray-smother-spray approach by killing the existing stand by spraying glyphosate in the late spring, plant a cover crop to smother any surviving toxic tall fescue, and then spray again in the fall prior to planting the novel endophyte tall fescue. Soil fertility should be maintain, stands should not be overgrazed during the summer months, and a rotational stocking system should be used to minimize the risk of losing stands of novel endophyte tall fescue. These steps can be taken to maintain strong productive stands without incidence of toxicosis.