Submitted to: Agriculture Ecosystems and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 2, 2005
Publication Date: December 15, 2005
Citation: Franzluebbers, A.J., Stuedemann, J.A. 2005. Early pasture and cattle responses to fertilization source and tall fescue-endophyte association in the Southern Piedmont USA. Agriculture Ecosystems and the Environment. 114:217-225. Interpretive Summary: Tall fescue is a common cool-season pasture species in the eastern USA that is naturally infected with a fungus, which produces chemical compounds that cause a variety of animal health symptoms from mild to severe toxicoses. Suggestions have been made that toxic symptoms are exacerbated in pastures with animal manure application. On the other hand, the presence of the fungus in tall fescue appears to be essential for the fitness of the grass to survive in stressful environments. A selected strain of the fungus that produces low levels of toxic ergot alkaloids has been isolated and inserted into tall fescue cultivars. Scientists at the USDA-ARS in Watkinsville GA evaluated pasture composition and beef stocker performance and weight gain from three fungus combinations (none, selected, wild) with ‘Jesup’ tall fescue and fertilized with either inorganic fertilizer or with poultry litter. Poultry litter had no adverse effects on cattle characteristics. The selected fungus produced high cattle performance and weight gain like the fungus-free. Seasonal variation in cattle performance due to fungus combinations suggests opportunities to manage wild fungus-infected tall fescue to avoid negative beef production consequences.
Technical Abstract: Development of tall fescue cultivars with a novel strain of endophyte that produces low ergot alkaloid concentration has raised new questions as to the productivity and persistence of tall fescue pastures in the southeastern USA. We determined botanical composition, forage and cattle productivity, and cattle stocking responses to tall fescue–endophyte association (free, novel, and wild endophyte associated with ‘Jesup’ cultivar) and fertilizer source (inorganic and broiler litter). Fertilizer source had only minor or no effects on response variables. Pastures with wild endophyte either had higher forage mass during some periods or were able to carry more cattle than other endophyte associations. Cattle gain in winter was not different (102 kg/ha), was lower in spring with wild than with other endophyte associations (206 vs 253 kg/ha), was higher in summer with wild endophyte (129 vs 103 kg/ha), and was lower in autumn with wild endophyte (188 vs 235 kg/ha). Novel endophyte associations could be successfully utilized to improve cattle performance and productivity compared with wild endophyte, but more long-term data are needed to evaluate whether persistence could be improved compared with endophyte-free tall fescue.