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Foraging Quality And Performance Of Yearlings Grazing Switchgrass Strains Selected For Differing Digestibility, Bruce Anderson, J. K. Ward, K. P. Vogel, M. G. Ward, Francis A. Haskins, Herman J. Gorz
Foraging Quality And Performance Of Yearlings Grazing Switchgrass Strains Selected For Differing Digestibility, Bruce Anderson, J. K. Ward, K. P. Vogel, M. G. Ward, Francis A. Haskins, Herman J. Gorz
Department of Agronomy and Horticulture: Faculty Publications
Switchgrass (Panicum virgatum) is a native, perennial warm-season grass commonly used as summer pasture. Three strains of switchgrass with different in vitro DM disappearance (IVDMD) values were evaluated with yearling cattle (Bos taurus) in three replicated grazing trials. All strains were similar in genetic background, maturity and yield potential. 'Trailblazer' (high-IVDMD) resulted in higher (P < .05) ADG than 'Pathfinder' and 'low-IVDMD'. Available forage of Trailblazer had higher IVDMD than Pathfinder and low-IVDMD. The IVDMD differences among strains were similar throughout the season; IVDMD declined between 0.3 and 0.5 percentage units per day. Forage availability, CP, NDF and ADF, permanganate lignin and ash were similar among strains. This study documents that plant breeders can select switchgrass plants for higher IVDMD and that strains consisting of progeny of these plants can result in higher animal gains than strains consisting of progeny of unselected or low-IVDMD plants with similar genetic background, forage yield, maturity, morphology and chemical composition.
Forage Quality And Performance Of Yearlings Grazing Switchgrass Strains Selected For Differing Digestibility, Bruce Anderson, J. K. Ward, K. P. Vogel, M. G. Ward, Herman J. Gorz, Francis A. Haskins
Forage Quality And Performance Of Yearlings Grazing Switchgrass Strains Selected For Differing Digestibility, Bruce Anderson, J. K. Ward, K. P. Vogel, M. G. Ward, Herman J. Gorz, Francis A. Haskins
Department of Agronomy and Horticulture: Faculty Publications
Switchgrass (Panicum virgatum) is a native, perennial warm-season grass commonly used as summer pasture. Three strains of switchgrass with different in vitro DM disappearance (IVDMD) values were evaluated with yearling cattle (Bos taurus) in three replicated grazing trials All strains were similar in genetic background, maturity and yield potential. 'Trailblazer' (high-IVDMD) resulted in higher (P < .05) ADG than 'Pathfinder' and 'low-IVDMD'. Available forage of Trailblazer had higher IVDMD than Pathfinder and low-IVDMD. The IVDMD differences among strains were similar throughout the season; IVDMD declined between .3 and .5 percentage units per day. Forage availability, CP, NDF and ADF, permanganate lignin and ash were similar among strains. This study documents that plant breeders can select switchgrass plants for higher IVDMD and that strains consisting of progeny of these plants can result in higher animal gains than strains consisting of progeny of unselected or low-IVDMD plants with similar genetic background, forage yield, maturity, morphology and chemical composition.
Escape Protein Supplementation Of Yearling Steers Grazing Smooth Brome Pastures, S. J. Anderson, Terry J. Klopfenstein, V. Wilkerson
Escape Protein Supplementation Of Yearling Steers Grazing Smooth Brome Pastures, S. J. Anderson, Terry J. Klopfenstein, V. Wilkerson
Department of Animal Science: Faculty Publications
Two grazing trials utilizing individually supplemented yearling steers were conducted to study the effect of supplemental escape protein on steer performance during the active growth periods, spring and fall, of smooth brome (Bromus inermis). Graded levels (0, .11, .23 and .34 kg x head-1 x d-1) of an equal-protein-basis mixture of bloodmeal and corn gluten meal were offered daily, replacing corn starch, which was used as the negative control. All steers received 582 g supplemental dry matter per day. Supplementation with escape protein improved daily performance in both spring (P<.01) and fall (P<.02). Analysis of pooled data from both trials indicated a linear (P<.01) and quadratic (P<.05) increase in steer performance with increasing level of escape protein in the diet. Analysis of grass samples collected throughout and composited over each trial demonstrated that grass protein was highly degraded in the rumen. Using a modified dacron bag technique, 12-h degradability was found to be 80 to 90% of the potentially digestible protein fraction. Rates of protein degradability were 14 and 11.7%/h. Assuming 5%/h rate of passage, escape protein was calculated to be 9.2 and 13.1% of total protein. As a result of the significant growth response observed above that of the energy-supplemented controls and the high ruminat protein degradabilities of the grass observed in the laboratory, it was concluded that growing ruminants grazing actively growing smooth brome pastures were deficient in metabolizable protein.