Wednesday, November 15, 2006

Effects of bale diameter, storage location, and sampling depth on the nutritive value, ruminal in situ disappearance kinetics of DM, and concentrations of ergovaline for endophyte-infected tall fescue hay packaged in large round bales.

Rebecca Norman1, Wayne Coblentz2, Charles F. Rosenkrans Jr.1, Donald Hubbell III1, Robin K. Ogden1, Kenneth P. Coffey1, and Joseph Kuznia3. (1) Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, (2) USDA-ARS, University of Wisconsin Marshfield Agricultural Research Station, 8396 Yellowstone Drive, Marshfield, WI 54449, (3) University of Arkansas, 17643 628th Ave., Janesville, AR 56048

During 2004, endophyte-infected tall fescue (Festuca arundinacea Schreb.) was packaged in large-round bales made at three diameters in Fayetteville (1.11, 1.35, or 1.59 m) and Batesville (1.14, 1.39, or 1.67 m), and then stored over winter either inside or outside on wooden pallets. Bales were then sampled at three depths (0 to 0.15 m, 0.15 to 0.31 m, and 0.31 to 0.46 m) to assess the effects of exposure on nutritive value, ruminal in situ disappearance kinetics of DM, and concentrations of ergovaline. At both locations, bale diameter had little effect (P > 0.05) on any response variable. Generally, there was little deterioration of nutritive value during the storage period, regardless of treatment. At both sites, there was no difference (P > 0.05) between the surface and internal bale layers for measures nutritive value when bales were stored inside. In contrast, concentrations of CP, NDF, ADF, and lignin were greater (P < 0.028) in the surface layer for bales stored outside at Fayetteville. Similar, but sharper, responses (P < 0.003) were observed for CP, ADF, lignin, and ash at Batesville. Parameters associated with ruminal disappearance kinetics of DM exhibited some differences (P < 0.05) in response to treatment, but these were largely minor, except for comparisons of the bale surface with internal layers for bales stored outside at Batesville. In that case, a 60 g/kg reduction (P < 0.0001) in effective ruminal disappearance of DM was observed. Concentrations of ergovaline were not affected (P > 0.05) by baling treatment at Batesville (overall mean = 247 ug/kg); however, at Fayetteville, respective reductions in ergovaline of 74 and 79% were observed between standing forage (539 ug/kg) and samples taken from baled hay before (141 ug/kg) and after storage (111 ug/kg).