Evaluation of Forage Nutritive Value and Dry Matter Yield of Stockpiled Tall Fescue Across Plant Hardiness Zones 7 and 8

Pastures in Tennessee comprise mainly tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.], a cool-season perennial grass. Tennessee producers feed hay for an average of 143 days per year, there is interest in utilizing stockpiling to extend the grazing season. Although this practice has been proven to reduce hay needs (Freeman et al., 2019), it is vital to maintain up-to-date recommendations using data from across the southeastern US to inform nutritional management decisions. The objective of this study is to determine the nutritive value and dry matter yield of stockpiled tall fescue across plant hardiness zones 7 and 8. Fourteen farms across Tennessee and Alabama were identified as sampling sites. In September 2021, three exclusion cages (4 ft × 4 ft) were constructed at each site, forage was clipped to a 2-inch height, and plots were fertilized at a rate of 60 lb. N/ac. During years 2021-2022 and 2022-2023, samples were clipped at a 2-inch height from a 1 ft² quadrat monthly from October through February. Data were analyzed using PROC GLIMMIX for a completely randomized design. Results indicate that plant hardiness zone did not have a significant effect on forage yield (P = 0.2098). Dry matter yield increased over the length of the stockpiling period (P < 0.0001) from 2,354 lbs. DM/ac to 4,391 lbs. DM/ac. Crude protein (CP) and total digestible nutrients (TDN) concentrations decreased (P < 0.0001 and P = 0.0358, respectively) throughout the stockpiling period; however, ranges were still within those needed to support the nutritional needs of a lactating cow with CP ranging from 15 – 17% and TDN ranging from 68 – 70%. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations increased over the stockpiling period (P = 0.0029 and P = 0.0145, respectively) as plants mature. Results from this study conclude that stockpiled tall fescue in plant hardiness zones 7 and 8 can support the nutritional requirements of mature cows at all stages of production through winter months. Results will be used to inform Extension recommendations to assist producers in making management decisions that increase grazing days and reduce supplemental feed input costs.