Sheep liveweight production from lucerne, cocksfoot or ryegrass based pastures

Abstract

Sheep liveweight (LW) production and total annual DM yields of four dryland cocksfoot (CF) based pastures (sown in combination with subterranean (Sub), balansa (Bal), white (Wc) or Caucasian (Cc) clovers); a perennial ryegrass (RG)/white clover control pasture and a lucerne (Luc) monoculture were compared for five growth seasons (2003-2008). Stock were managed to optimise production from each pasture type in each season and this included continuous and rotational grazing. Annual LW production from lucerne (833- 1110 kg/ha/y) was superior to all grass based pastures in three of the five years largely due to similar spring but superior summer animal and crop production. Over five years, spring LW production was the most consistent and, averaged over treatments and years, represented 64% of total annual LW production. In contrast, LW production over summer months was variable and accounted for 15-33% of total annual LW production. Generally, LW production was low when summer rainfall was below average (<142 mm) and higher when summer rainfall was average or above. Autumn production was 2-4% of annual LW production after a productive (moist) summer and 17-26% after a dry summer. Of the grass based pastures, LW production was greatest from CF/Sub due to superior spring growth, particularly in Years 2, 3 and 5. Overall, the results indicated a range of pasture species were required in dryland systems to cope with seasonal and annual variability in rainfall.