The substrate used in these experiments was low-quality grass hay harvested from native
prairie in the eastern area of Kansas State (USA) and whose primary species included
Andropogon gerardii, Sorghastrum nutans, Panicum virgatum, and Schizachyrium scoparium.
Forage was ground through a 1mm screen using a Willey-mill (Thomas Scientific,
Swedesboro, NJ, USA). The CP concentration of the grass hay was 53 g/kg and the NDF
concentration was 761 g/kg on a DM basis