Daren D. Redfearn1, Robert B. Mitchell2, Kenneth Vogel3, John A. Guretzky1, Terry Klopfenstein4 and Jim MacDonald5, (1)Agronomy & Horticulture, University of Nebraska - Lincoln, Lincoln, NE (2)USDA-ARS, Lincoln, NE (3)University of Nebraska - Lincoln, Lincoln, NE (4)Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE (5)Department of Animal Science, Univesity of Nebraska-Lincoln, Lincoln, NE
Smooth bromegrass (Bromus inermis Leyss.) is the most widely used pasture grass in the Midwest and Northeastern USA. Likewise, meadow bromegrass (Bromus riparius Rehm.) can also be used in this region. It is less productive than smooth bromegrass, but can have better regrowth. Thus, a comparison is needed between a traditional and newly-released smooth bromegrass cultivar with an experimental strain of meadow bromegrass (NE BR1) for use in complementary forage systems. The objective of this study was to determine if yield and in vitro dry matter digestibility (IVDMD) improvements in ‘Lincoln’ smooth bromegrass (released as ‘Newell’ in 2014) resulted in increased beef cattle performance and body weight gain per area compared with those obtained with Lincoln smooth bromegrass and NE BR1 which was bred for use in this region. This study was established in 2009 as a completely randomized design with three replicates of each bromegrass strain. The three bromegrass strains were seeded as monocultures in three, 0.4 ha pastures. Pastures were stocked with three yearling steers. Average daily gain (ADG) and body weight gain ha-1 were determined from spring grazing of initial growth. Forage samples were collected weekly during grazing in each pasture from three, 30 cm x 182 cm quadrats by clipping to a 4.0 cm stubble height to determine available forage. This forage was composited, weighed, and subsampled for nutritive value analyses. Averaged across the 3-year grazing trial, forage samples collected during grazing had similar IVDMD and crude protein (CP) concentrations, but IVDMD and CP were typically greater for meadow bromegrass. The ADG was similar for Lincoln (1.29 kg animal-1 d-1) and the experimental meadow bromegrass strain (1.33 kg animal-1 d-1), but Newell had greater and more consistent ADG (1.43 kg animal-1 d-1) across all three years of the study. Mean body weight gain was greater for Newell (159 kg ha-1) than the experimental meadow bromegrass strain (147 kg ha-1) or Lincoln (141 kg ha-1). During 2013, both ADG and body weight gain were similar for all bromegrass strains suggesting some resiliency to recover following an extensive, short-term drought that occurred during 2012. The similar agronomic performance, animal performance, and drought recovery indicates that the experimental meadow bromegrass strain, NE BR1, may offer another forage option for use as a component of complementary forage systems in the western Corn Belt.