Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/6/2005
Publication Date: 6/11/2005
Citation: Looper, M.L., Aiken, G.E., Tabler, S.F., Flores, R., Rosenkrans, C.F., Miesner, J.R. 2005. Quantity, quality, and ergovaline concentrations of burned stockpiled tall fescue. American Forage and Grassland Conference Proceedings. 14:196-200. Interpretive Summary: Tall fescue is a commonly stockpiled cool-season forage that reduces supplemental feeding and generally exceeds the recommended nutrient requirements of both lactating and non-lactating beef cows. However, the effects of fire on the nutritive characteristics of stockpiled regrowth have not been examined. Nutritive content of tall fescue regrowth after burning met or exceeded the nutrient requirements of beef cows, however, forage availability was limited by fire, and concentrations of ergovaline were increased to concentrations that may cause fescue toxicosis in cattle. This information is important to beef producers utilizing stockpile fescue, extension personnel, and agricultural professionals who advise beef producers utilizing stockpiled fescue.
Technical Abstract: Tall fescue is a commonly stockpiled cool-season forage in the Southeastern United States that generally exceeds the recommended nutrient requirements of both lactating and non-lactating beef cows. However, the effects of fire on the nutritive characteristics of stockpiled tall fescue of residual burned forage and subsequent regrowth have not been elucidated. Objectives of this experiment were to determine the quality, quantity, and ergovaline concentrations of stockpiled tall fescue destroyed by fire. Six pastures were clipped to a height of 4 in and fertilized (26 September) with 36 lb N/acre to initiate the stockpiling process for a grazing experiment utilizing market beef cows. On 2 December, one-half of one 40 acre pasture was destroyed by fire. The burned pasture was fertilized with 17 lb N/acre on 10 December, and in the spring (27 February) with 65 lb N/acre. The pasture was characterized three times (5 December, 3 February, and 27 April) during the experiment to determine forage availability and nutritive value. Forage samples were randomly selected from pasture to determine concentrations of ergovaline at the three sample dates. At the initiation, forage availability was 1862 lb DM/acre and concentration of ergovaline was 1562 ppb. Overall, the nutritive content of the burned stockpiled tall fescue averaged 15.8% CP, 33.5% ADF, and 63.5% digestible. Nutritive content of stockpiled tall fescue destroyed by fire may meet or exceed the nutrient requirements of beef cows. However, forage availability may be limited by fire, and concentrations of ergovaline in burned stockpiled fescue may be increased to concentrations that cause fescue toxicosis in cattle.