Stand Persistence and Animal Performance for Tall Fescue Endophyte Combinations in the South Central USA

Abstract

Infection by an endophyte [ Neotyphodium coenophialum (Morgan‐Jones & Gams.) Glenn, Bacon, & Hanlin comb. nov.] can improve persistence of tall fescue ( Lolium arundinaceum (Schreb.) S.J. Darbyshire = Festuca arundinacea Schreb.). Novel endophytes may minimize toxicity problems associated with wild‐type endophytes, thus encouraging tall fescue use in the south central USA. The objectives of these studies were to compare stand persistence and grazing animal performance among tall fescue cultivars with different fungal endophyte combinations in the south central USA. Trials were planted in 1999 in Oklahoma and Louisiana. Tall fescue entries contained no endophyte (‘GA‐5’ E−, ‘Dovey’), a novel endophyte (‘Jesup’ MaxQ, ‘GA‐5’ MaxQ), or a wild‐type endophyte (‘KY‐31’ E+, ‘GA‐5’ E+). Weight gain data for beef cattle ( Bos taurus ) were collected during fall and/or spring. Estimates of stand persistence were collected periodically. In Oklahoma, average daily gain (ADG), at 0.71 kg d −1 , did not differ between entries in fall. During spring, ADGs (kg d −1 ) were greater from Dovey (0.64), GA‐5 MaxQ (0.67), and GA‐5 E− (0.56) than from KY‐31E+ (0.29) and were intermediate for GA‐5E+ (0.47). In Louisiana, ADGs were greater from GA‐5 E− (1.20), GA‐5 MaxQ (1.06), and Jesup MaxQ (1.12) than from GA‐5E+ (0.76). In Oklahoma, stands were greater than 80% 4 yr after establishment. In Louisiana, stands declined in some E− paddocks 3 yr after planting. Thus, E− and novel endophyte–infected tall fescue resulted in greatest animal performance, whereas wild‐type and novel endophyte infection led to enhanced stand longevity. However, improved persistence is needed for broader adaptation of tall fescue to the south central USA.