Author
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Aiken, Glen |
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Submitted to: Hay and Forage Grower
Publication Type: Popular Publication Publication Acceptance Date: 3/26/2016 Publication Date: 3/30/2015 Citation: Aiken, G.E. 2015. Novel endophyte provides fescue toxicosis relief. Hay and Forage Grower. Pgs. 24 & 25. Interpretive Summary: There is approximately 35 million acres of tall fescue in the USA that is predominately in the transition zone between the subtropical southeast and the temperate northeast; a region collectedly referred to as the “Fescue Belt”. Most tall fescue is infested with a fungal endophyte that produces alkaloids that impart the plant with tolerances to environmental stresses; unfortunately, it also produces ergot alkaloids that induce a toxicosis in cattle. Signs of toxicosis are: 1) elevated body temperature which causes them to be vulnerable to heat stress in moderate air temperatures, 2) maintaining rough hair coats during the summer, 3) low prolactin (hormone required for milk production), and 3) poor performance (weight gain, reproduction, and milk production) and thriftiness. There is another option, which is to replace toxic endophyte-infected tall fescue with non-toxic endophyte infected tall fescues, but there are certain considerations when establishing and grazing non-toxic endophyte fescues. Prior to planting novel-endophyte fescue, the existing toxic endophyte fescue must be killed and volunteer emergence of toxic endophyte fescue must be controlled. Stands of non-toxic endophyte fescue also should not be overgrazed during late spring and the summer when the novel endophyte tall fescue is vulnerable to overgrazing. It also is highly recommended that a rotational stocking system be used to allow recovery growth and rotate cattle when pastures heights are 3 to 4 inches. Novel endophyte-infected tall fescue will require more inputs of management than toxic endophyte-infected tall fescue, but cattle producers in the fescue belt now have an alternative to toxic tall fescue that is sustainable and persistent under good management. Technical Abstract: Tall fescue is extremely persistent and productive in the climatic and soil conditions in the fescue belt, which makes it extremely challenging to replace toxic endophyte-infected tall fescue with non-toxic grass alternatives. There is another option, which is to replace toxic endophyte-infected tall fescue with non-toxic endophyte infected tall fescues. An article was written to discuss certain considerations when establishing and grazing non-toxic endophyte fescues: 1) prior to planting novel-endophyte fescue, the existing toxic endophyte fescue must be killed and volunteer emergence of toxic endophyte fescue must be controlled, 2) do not overgraze non-toxic endophyte fescue during late spring and the summer when there is less active fescue growth and the novel endophyte tall fescue is vulnerable to overgrazing, and 3) use a rotational stocking system to allow recovery growth and rotate cattle when pastures heights are 3 to 4 inches. Seed heads should be controlled to inhibit potential encroachment of toxic endophyte-infected tall fescue, which can be done by mowing, grazing, or chemical means. Novel endophyte-infected tall fescue requires more management than the toxic endophyte-infected tall fescue, but can persist and alleviate fescue toxicosis. |
