Grazing influences on mass, nutritive value, and persistence of stockpiled Jesup tall fescue without and with novel and wild-type fungal endophytes

Introducing novel endophytes into tall fescue (Festuca arundinacea Schreb.) that produce no ergot alkaloids could prevent negative impacts on animal performance while improving plant persistence. This 3-yr study evaluated 'Jesup' tall fescue (TF) for forage mass, nutritive value, and stand persistence when containing no endophyte, a novel endophyte (no ergot alkaloids), or a wild-type endophyte (ergot alkaloids). Forage was accumulated from mid-August and treatments consisted of (i) a grazed control (grazed when growth approximated 10 to 15 cm), or forage accumulated and grazed in (ii) mid-November, (iii) mid-December, (iv) mid-January, and (v) mid-February. Endophyte status had no influence on total forage mass; forage removed by grazing; proportion of leaf, stem, and dead fractions; or on nutritive value (except ergovaline which was greatest in the wild type). Delaying defoliation linearly reduced forage mass, ergovaline concentration, and nutritive value. All stands of TF declined with losses similar (P = 0.37) for wild-type and novel stands (29 vs. 42%) but were greatest for the TF without an endophyte (29 vs. 75%; P = 0.01 and 42 vs. 75%; P = 0.04). These data support the use of novel endophytes in TF for animal production and caution against the use of endophyte-free TF because of decreased stand longevity. The presence of ergovaline can be minimized by stockpiling TF with utilization after late autumn but occurs with a sacrifice in forage mass and nutritive value.