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Reinfestation of Endophtye‐Infected Tall Fescue in Renovated Endophyte‐Free Pastures under Rotational Stocking
Author(s) -
Tracy Benjamin F.,
Renne Ian J.
Publication year - 2005
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2004.0304
Subject(s) - pasture , endophyte , grazing , festuca arundinacea , stocking , agronomy , biology , cultivar , poaceae , zoology , botany
Endophyte‐infected (E+) tall fescue [ Lolium arundinaceum (Schreb.) S.J. Darbyshire] is problematic in pastures because it produces alkaloids that can be toxic to cattle ( Bos taurus ). Replacement of E+ tall fescue pasture with endophyte‐free (E−) fescue may effectively eliminate this problem. Endophyte‐free cultivars, however, are less competitive than E+ fescue and are usually displaced over time. The main objective of this study was to determine whether E+ fescue would reinfest pastures planted with mixtures of E− fescue and other species and grazed under rotational stocking. In 2001, nine tall fescue pastures in western Illinois were renovated and planted with mixtures that contained E− fescue (Barcel) and two, four, or seven additional species. Pastures were grazed by beef cattle over 3 yr. Tall fescue tillers were collected each September and subjected to microscopic analysis for endophyte presence. After renovation, E+ still accounted for 18 to 38% of tall fescue. Relative to all other species, however, E+ fescue was <10% of pasture communities. The species mixtures sown with E− fescue had little influence on E+ fescue reinfestation ( P = 0.70). Contrary to other studies, percentage of E+ fescue in E− pastures did not increase in the 3 yr of this study. Moderate grazing pressure under rotational stocking combined with relatively wet growing seasons likely favored E− fescue and suppressed E+ reinfestation. We also suggest that if pasture renovation can reduce E+ fescue percentage to <10%, it is unlikely that E+ fescue will reinfest pastures to an extent that may cause fescue toxicosis in cattle.