Integrating annual and perennial warm-season grasses in a temperate grazing system

Warm-season grasses (WSG) can supply badly needed forage in summer when cool-season grasses (CSG) are often unproductive. This study was conducted from 2005-2007 in central Illinois to compare annual and perennial WSG pasture types integrated into a CSG grazing system. The objective was to compare summer herbage mass, forage nutritive value, cattle (Bos taurus) performance, and variable costs between CSG systems integrated with either annual (AWSG) or native, perennial warm-season grass (NWSG) pastures. The AWSG pastures were established with sorghum-sudangrass cultivars [Sorghum bicolor (L.) Moench], and eastern gamagrass [Tripsacum dactyloides (L.) L.] dominated NWSG pastures. Beef cow--calf groups were moved between CSG and WSG pastures during summer based on forage availability. Both WSG pasture types averaged 61% more herbage mass (493 g [m.sup.-2]) in mid-summer compared with CSG pastures (204 g [m.sup.-2]). Except for one sampling date, herbage mass on NWSG pastures either exceeded (P < 0.05) or was equal to AWSG pastures. The nutritive value of AWSG forage was consistently higher than NWSG (P < 0.05), but cow and calf performance was similar on both pasture types. A simple cost analysis showed that AWSG pastures were more expensive to maintain even though establishment costs of NWSG pasture were much higher. Our results suggest NWSG pastures may be the better option for livestock producers seeking a longer-term solution to summer forage deficits associated with CSG. doi: 10.2135/cropsci2010.02.0110