YIELD, QUALITY, AND TOXICITY OF STOCKPILED TALL FESCUE

摘要

Many livestock producers use stockpiled tall fescue (Festuca arundinacea Schreb.) to extend the grazing season into winter. Tall fescue (TF) infected with new non-toxic endophytes have not been studied for stockpiled yield, forage quality, and toxicity. Our objective was to determine the yield, forage quality, and ergovaline content of TF infected with a native endophyte (K31 E+), a non-toxic endophyte (HiMag NTE), and with no endophyte (HiMag E-) through the entire winter. Plots of K31 E+, HiMag E-,and HiMag NTE were established at the Southwest Missouri Center in fall 1998. Forage yield, quality, and ergovaline content were measured monthly from mid-December through mid-March in 1999-2000 and 2000-2001. Forage yield did not change from mid-December through mid-March for any entry. All entries had similar levels of ADF on comparable dates. Neither HiMag E- nor HiMag NTE contained any ergovaline, but K31 E+ had substantial levels of ergovaline in both years. The ergovaline content in K31 E+ declined approximately 6 fold from December to March each year. The stable yield, slowly declining forage quality, and rapidly falling ergovaline levels in K31 E+, suggest that livestock producers could minimize winter toxicosis by delaying the use of stockpiled K31 E+ until mid or late winter.