USING DRYLAND LUCERNE TO FINISH OUT-OF-SEASON PRIME LAMBS

摘要

A grazing experiment was conducted with lucerne (Medicago sativa) sown on a red chromosol in 1998, at a site near Corowa NSW, which has an average annual rainfall of 506 mm. Second-cross wether lambs, born in July or August in each year, were weaned onto the lucerne in the late spring of 1999, 2000 and 2001. The lambs were split into 3 groups and grazed 0.27 ha subplots as follows: 1) 7 lambs per plot were moved onto fresh lucerne every 2 1/2 weeks in a 3 paddock rotation (RT), to represent the traditional time-based grazing practice for lucerne; 2) 7 lambs per plot were moved onto fresh lucerne in a 3 paddock rotation when lucerne had been grazed to a residual of 800 kg DM/ha (RF), to optimise lamb growth rates; and 3) in a 2 paddock rotation, 7-28lambs per plot were moved onto annual pasture whenever lucerne DM had been grazed to a residual of 500 kg DM/ha (FG/AP), and returned when lucerne regrowth had reached 800 kg DM/ha. This represented a likely rotation on cropping farms with large paddocks. All treatments were replicated 4 times. No supplementary feed, was supplied and lambs were weighed each time they were moved. When lucerne regrowth had ceased, all lambs were removed from the plots and slaughtered; carcass data were collected in 2000and 2001.