The objective ofthis trial was to study the dynamics of pasture containing black oat (Avenastrigosa Schreb) plus ryegrass (Lolium multiflorum Lam) on beef heifersreceiving different levels of supplementation. The following treatments wereused: 'No Supplement'- animals in black oat plus ryegrass pasture; 'Increasing'- animals in black oat plus ryegrass pasture and fed increasing levels of supplement:0.3; 0.6; 0.9; and 1.2 to 1.5% of body weight (BW) during the pasture cycle;'Fixed' - animals in black oat plus ryegrass pasture and fed 0.9% of BW as supplementduring the entire pasture cycle; or 'Decreasing' - animals in black oat plusryegrass pasture and fed decreasing levels of supplement: 1.5; 1.2; 0.9; and0.6 to 0.3% of BW during the pasture cycle. The supplement contained only wheatbran. The following variables were measured: forage yield, rate of daily accumulationof DM, forage allowance, green leaf allowance, green forage mass, and leaf:stemratio. Oat leaf, oat stem, ryegrass leaf, ryegrass stem, and dead material allexpressed as a percentage of FM were also evaluated. The nutritive value ofthe forage apparent consumed by the heifers was determined through measurementsof contents of crude protein (CP), 'in vitro' organic matter digestibility,total digestible nutrients, and neutral detergent fiber. Although pasture cycledid affect the studied variables, the opposite was observed with different levelsof supplementation in the current trial.
