National ADSA Foods Only (Graduate): ADSA Dairy Foods Graduate Paper Contest

A four-year trial was initiated in January 2000 to evaluate forage production, basal cover, and persistence of endophyte-infected tall fescue (IF; Festuca arundinacea Schreb.), endophyte-free tall fescue (FF), or orchardgrass (OG; Dactylis glomerata L.) overseeded into dormant common bermudagrass [Cynodon dactylon (L.) Pers.] for spring-calving cows. The FF and OG pastures were managed with either a twice weekly (HM) or twice monthly (LM) rotation schedule, while the IF pastures were managed with a LM rotation schedule only. Forage-related response variables were evaluated with a split-plot design, where forage system (IF-LM, FF-HM, FF-LM, OG-HM, and OG-LM) was the wholeplot term and sampling/evaluation date was analyzed as a repeated measure. Forage availability (four-year mean = 3809 kg/ha) was not affected (P = 0.601) by forage management system, but was affected by sampling date (P < 0.0001) and the forage system x sampling date interaction (P = 0.010). Total basal cover varied (P < 0.0001) with sampling date, ranging from 36.3 to 51.5%, but was not affected by forage system (P = 0.679) or the interaction of main effects (P = 0.354). The interaction of forage system and evaluation date affected (P = 0.038) the percentage of the desired cool-season species in each pasture. Generally, FF and IF remained relatively stable over the entire study, ranging from 49.2 to 72.5% for FF-HM, 54.0 to 73.5% for FF-LM, and 46.9 to 65.8% for IF. However, the percentage of OG declined markedly (P < 0.1) since June 2002 in both the HM and LM grazing systems, ending at 36.2 and 14.7%, respectively, on the final (November 2003) evaluation date. After four years, FF has persisted well, but OG stands have thinned markedly, particularly under the LM rotation schedule. Therefore, FF may be a better choice than OG as an alternative to IF for spring-calving cow herds in the Upper South.