OLD SERA008: Fescue Endophyte Research and Extension (IEG-37)
Statement of Issues and JustificationProject's Primary Website is at http://animalscience.ag.utk.edu/SERA-IEG8/default.htm (direct link can be found under LINKS)
Tall fescue is the most widely grown cool-season pasture grass in the U.S. Over 35 million acres of tall fescue are infested with Neotyphodium coenophialum, a fungal endophyte that costs cattle producers $560 million /year in reduced calf numbers and $233 million /year in reduced weaning weights. Endophyte-infected tall fescue causes cattle to experience reduced growth rate, increased reproductive problems, and poor milk production. Additionally, it causes similar problems in mares, including production of dead foals and other foaling difficulties as well as agalactia.
Despite its toxic endophyte, tall fescue remains the mostly widely grown pasture grass from eastern edge of North Carolina west to eastern Oklahoma and from central Alabama north to northern Missouri. Its popularity with livestock producers is based on its wide range of adaptation, its long growing season, and its persistence. Tall fescue persists by withstanding stresses from drought, disease, and insects.
In the mid-1980's, endophyte free tall fescues were released. Because they did not contain the toxic endophyte, these cultivars increased steer weight gains 30 to 100 percent. The endophyte-free tall fescues also provided normal conception and milk production. However, the new cultivars were less persistent. Research in the last decade has shown that the endophyte-grass association is muturalistic. Tall fescue provides the host for the endophyte, while the endophyte helps tall fescues tolerate drought, resist pests, survive grazing and compete in a mixed sward.
Much remains to be done to understand the mechanism(s) of endophyte toxicity and to assist producers in management of endophyte-infected pastures. New technologies in which the characteristics of the endophyte are being investigated as well as the transfer of non-toxic novel endophytes into endophyte-free plants should lead to long term solutions for fescue toxicosis but with a very desirable plant. It is though the efforts of the participants of this group that four international symposiums on grass/endophyte interaction have been held. The last one being held in September 2000 in Soest, Germany.
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