Review: Utilization of Stockpiled Tall Fescue in Winter Grazing Systems for Beef Cattle

Stockpiling of autumn growth of tall fescue for winter grazing is a forage system that has great potential to reduce cow wintering costs, improve the environmental impact of winter feeding systems, and potentially improve animal health and welfare. Research before 1999 focused on the nutritive value of stockpiled forage as influenced by N fertilization level, date of fertilization and initiation of accumulation, and harvest date. One recent study suggests that the N source is an important determinant of the efficiency of N use, but there is still a general lack of information on the relative effectiveness of various N sources. Studies in the peer-reviewed literature before 1999 that evaluated animal responses suggested that endophyte infection might reduce animal performance, resulting in lower performance than expected from the forage nutritive value. A review of recent literature showed that endophyte infection status appears to have little effect on the winter performance of growing cattle or brood cows. Reductions in ergot alkaloid toxins during the wintering season might explain in part the similar performance with endophyte-free, wildtype toxic-infected, or novel infected tall fescue. However, the observation that performance and DMI in growing cattle grazing stockpiled fescue is lower than expected still deserves additional attention. The frequency and level of forage allocation may affect forage intake, but there is little research to support general recommendations. In the one available study, increasing forage allocation increased forage intake and decreased forage utilization efficiency but had little effect on calf weaning weight or cow breeding rate. Supplementation of cattle grazing stockpiled tall fescue has been reported by several authors. Results suggest that cattle will respond to energy supplementation when forage CP is high (> 14%), and that there may be additional responses to CP supplementation when forage CP is marginal (< 12%). Because of the variable CP and energy content of stockpiled fescue and apparently low DMI in growing cattle, additional research is needed to clarify optimal supplementation programs. The impact of stockpiled fescue grazing, as opposed to traditional hay-feeding systems, on animal health and the environment are important subjects for future research.