| The carrying capacity of adjacent irrigated pastures seeded to monocultures of orchardgrass (OG), tall fescue (TF), or perennial ryegrass (PRG) was measured using crossbred yearling beef heifers (360 kg). Pastures were flood irrigated and received ammonium nitrate fertilization before each irrigation. Management intensive grazing practices were used with the daily pasture allotments bounded by portable polywire electric fencing. Forage dry matter intake was measured using a corrected visual appraisal method before and after grazing. Changes in the body weight of the heifers was measured monthly through the 150-day grazing season. Carrying capacity of OG and TF were similar, 1403 and 1234 animal unit days/ha (P = 0.49), while PRG exhibited the lowest carrying capacity of 758 animal unit days/ha (OG vs. PRG, P = 0.12; TF vs. PRG, P = 0.06). Heifers grazing OG and TF gained 0.88 kg/day (P = 0.97). Those grazing PRG gain only 0.71 kg/day (P = 0.09). |
