|STUEDEMANN, JOHN - Retired ARS Employee
Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2012
Publication Date: 4/25/2013
Citation: Franzluebbers, A.J., Stuedemann, J.A., Seman, D.H. 2013. Stocker performance and production in mixed tall fescue-bermudagrass pastures of the Southern Piedmont USA. Renewable Agriculture and Food Systems. 28:160-172.
Interpretive Summary: Small-scale cattle producers want to know how to develop year-round grazing systems with robust forage combinations that can lead to greater sustainability. Mixing bermudagrass and tall fescue are logical choices in the southern region, but information is lacking on how these forages should be managed to obtain the best results. Scientists at the USDA Agricultural Research Service in Watkinsville Georgia conducted a grazing study in which tall fescue was introduced into a 5-year-old solid stand of bermudagrass and steer performance and production were measured throughout the 12 years of investigation. Stocker grazing of mixed tall fescue-bermudagrass pastures in the Piedmont of Georgia was highly successful in achieving adequate steer performance (1.3 lb/day) and steer production (771 lb/acre). Reducing grazing pressure to increase residual forage mass resulted in a reduction in steer stocking rate from 1.7 steers/acre to 1.5 steers/acre. However, the reduction in grazing pressure was able to increase steer performance from 1.3 lb/day to 1.4 lb/day. The shift from lower steer production with low grazing pressure early in the study towards greater steer production with low than with high grazing pressure later in the study was a significant outcome of this study. We conclude that excellent cattle performance and productivity can be achieved with broiler litter fertilization of strategically grazed pastures with mixed tall fescue-bermudagrass forage composition. Combined with results from botanical composition changes during this experiment (unpublished data), a strategically grazed system would rely on closely grazing the robust tall fescue component during late winter to early spring and moderately grazing the bermudagrass component during the summer and autumn. These results can be used by the thousands of small-scale cattle producers to improve the sustainability of grazing systems in warm, humid climates.
Technical Abstract: Stocker performance and production from mixed cool- and warm-season perennial pastures are important determinants of agricultural sustainability that can be influenced by management. We evaluated the factorial combination of three sources of nutrient application (inorganic only, organic + inorganic combination, and organic only) and two forage utilization regimes (low and high grazing pressure) on steer stocking density and rate, performance, and production during 7 yr of pasture management [tall fescue (Lolium arundinaceum) overseeded into existing Coastal bermudagrass (Cynodon dactylon) sod] on a Typic Kanhapludult in Georgia. Nutrient source had few major impacts on responses, except for lower animal performance with organic fertilization (broiler litter) than with organic + inorganic and inorganic only fertilization, especially with low grazing pressure. Seasonal changes in stocking weight and rate occurred, not only as expected due to environmental conditions and dominant forage species present, but that also counteracted expected differences imposed by grazing pressure; signaling negative feedback of high grazing pressure on forage productivity. Steer performance was greatest in spring and summer under both grazing pressures, but was significantly reduced with increasing grazing pressure in the autumn and winter due to low forage availability. Steer gain/ha across years (863 kg/ha) was not different between grazing pressures, but declined with time under high grazing pressure and was stable with time under low grazing pressure. Reducing grazing pressure to a moderate level can lead to equivalent steer production as higher grazing pressure, and would likely contribute to a more sustainable balance among production, socio-economic, and environmental goals. These multi-year results will help cattle producers in warm, moist climates design and implement more sustainable grazing systems.