Comparison of Chemical Composition and Rumen Degradation Kinetics of Three Forages: Whole Plant Barley, Whole Plant Foxtail Millet and Grass-Legume Hay
<p>The objective of this study was to determine the chemical composition and <em>in situ</em> rumen degradability of whole plant barley (<em>Hordeum vulgare</em>), whole plant foxtail millet (<em>Setaria italica</em>) and smooth bromegrass (<em>Bromus inermis</em> <em>Leyss</em>)-alfalfa (<em>Medicago sativa </em>L.) (grass-legume) hay, collected during a companion field grazing study. Relative to grass-legume hay, barley and millet were higher (P = 0.05) in crude protein (CP) and soluble CP, and lower (P = 0.02) in neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, neutral detergent insoluble CP, and acid detergent insoluble crude protein. The potentially undegradable fraction of CP averaged 32% lower for barley and millet, compared to grass-legume hay, while CP soluble fraction was 36 and 64% higher (P < 0.05) for barley and millet, respectively, than for grass-legume hay. Millet had the highest NDF degradability (P = 0.03) and grass-legume hay the least. Barley and millet had greater (P = 0.02) effective degradability of dry matter (DM), CP, and NDF than grass-legume hay. Millet had the highest (P = 0.01) degradable and lowest undegradable fractions of DM and NDF, and lowest soluble fraction of NDF and rate of CP degradation (P < 0.05). Results indicate that whole plant barley and millet have greater nutritive value than grass-legume hay and may be suitable annual forages for extensive grazing.</p>