Endophyte-Free Tall Fescue Potential for Pastures on Fertile Clay Loam Soils in Central Louisiana

Although endophyte-free tall fescue (Festuca arundinacea Schreb.) cultivars have been recognized as lacking persistence on droughty, infertile, sandy Coastal Plain soils, they have continued to be recommended for the more fertile and heavier bottomland soils in Louisiana. Two pasture experiments were conducted to assess animal performance on, and persistence of, endophyte-free genotypes on the fertile soil of central Louisiana. In the first experiment, performance of young, growing, crossbred beef cattle on AU-Triumph and Forager tall fescue pastures was compared with that on Marshall annual ryegrass (Lolium multiflorum Lam.) using put-and-take stocking over three growing seasons. In the second experiment, year-round stocking and stocking only in the cool season, with and without fall hay harvest, were compared with set-stocked AU-Triumph tall fescue pastures for 2 yr. Individual animal performance on annual ryegrass at 0.74 kg/d was greater than that on the two tall fescue cultivars, which averaged 0.57 kg/d and did not differ from each other. Although animal performance was affected by management of AU-Triumph tall fescue in the first year of grazing, responses in the second year did not differ. Only 2 or 3 yr of productive grazing were obtained from endophyte-free tall fescue in these experiments on central Louisiana clay loam soil. Disease damage from Rhizoctonia solani Kuehn. contributed to stand loss and appeared to hasten deterioration from summer stress and invasion by aggressive warm-season grasses. Results of these experiments and reports from other locations in Louisiana indicate that endophyte-free tall fescue is not sufficiently adapted for use as a pasture plant, even on the more productive Louisiana soils.