The Utilization of Smooth Bromegrass (Bromus inermis) under Rotational and Strip Grazing systems of Pasture Management. II. Digestibility-Intake Studies

Several naturally occurring and artificial indicators have been proposed to circumvent the total collection of feces in digestion trials (,1). The use of plant pigments as naturally occurring indicators in digestibility studies was first proposed by Reid et al. (8). In this procedure forages and feces were extracted in 85% acetone, and pigment concentrations were determined spectrophotometrically at 406 m~. The ratio of plant to fecal pigments was used to compute indigestibility. In later studies (7), formulas were derived which enabled the computation of either plant pigment concentration or digestibility of consumed herbage from fecal pigment concentrations. Use of either of these formulas precluded the manual sampling of herbage, thereby avoiding sampling error resulting from selective grazing.