The Effect of Harvest Moisture and Bale Wrapping on Forage Quality, Temperature, and Mold in Orchardgrass Hay

Effects of harvest moisture and bale wrapping on forage quality and mold formation in orchardgrass (Dactylis glomerata L) hay have not been investigated. The objectives of this study were to determine the effects of initial bale moisture and plastic wrapping on temperature, forage quality (protein, fiber components, and digestible energy), and mold formation in large round-baled orchardgrass hay. In all, 40 round bales of mature orchardgrass hay measuring 1.2 x 1.5 m(2) were baled at three different moisture ranges (eight bales per treatment): 124 to 166 g/kg (low moisture); 180 to 232 g/kg (intermediate moisture); and 259 to 337 g/kg (high moisture). Selected bales within each moisture range were individually wrapped in plastic (16 bales), and temperature sensors were placed in each bale for up to 10 weeks. The lowest (P <= .01) maximum temperature and heating degree-day accumulations were observed when initial bale moisture content was 124 g/kg or when hay was wrapped, regardless of initial moisture content. In 2008 and 2009, all wrapped hays resulted in similar forage quality (P <= .14) and mold counts = .94) compared with 124 g/kg moisture hay. Hay baled at 166 g/kg resulted in fiber (P >= .82) and mold (P = .21) components similar to higher moisture bales. Mold counts for hay baled at 166 g/kg and 124 g/kg moisture were 24.8 x 10(6) and 2.7 x 10(4) CFU/g, respectively, demonstrating that large round bales are prone to molding at relatively low moisture concentrations. Maintenance of forage quality and reduction in mold growth were achieved by baling dry (124 g/kg moisture) or wrapping round bales of orchardgrass hay up to 337 g/kg moisture. (C) 2011 Elsevier Inc. All rights reserved.