'MaxClover' grazing experiment II: Sheep liveweight production from six grazed dryland pastures over 8 years

Abstract

Liveweight production was quantified from six dryland pastures at Lincoln University, Canterbury, New Zealand, over an 8 year period. The experiment was a randomised complete block with six replicates. The pastures were established in autumn 2002 with cocksfoot (CF) and subterranean (CF/Sub), balansa (CF/Bal), white (CF/Wc) or Caucasian (CF/Cc) clovers, a perennial ryegrass/white clover (RG/Wc) control and a lucerne (Luc) monoculture. Liveweight (LWt) production from Years 2 (2003-04) to 9 (2010-11) was 7940 kg LWt/ha from the lucerne monoculture, 7270 kg LWt/ha from the CF/Sub pasture and 5680 ± 171 kg LWt/ha from CF/Bal, CF/Wc, CF/Cc and RG/Wc pastures. Annually, LWt production ranged from 443 kg/ha (CF/Wc pastures with hoggets grazing in spring in 2006-07) to 1285 kg/ha from CF/Sub pastures in Year 9 when ewes with twin lambs at foot grazed in spring. On average, grass-based pastures produced 64%-70% of their total annual LWt production in spring compared with 57% from lucerne monocultures. In spring, relationships between LWt and total spring DM yield showed that 7.3 ± 0.68 kg LWt/ha was produced per 100 kg total DM (R2 = 0.87) grown in 5 of the 6 years under the hogget/weaned lamb grazing system. Relationships between LWt and metabolisable energy or N yield failed to improve this relationship, which suggests that DM yield from persistent improved pasture components was the major factor responsible for differences in LWt production from these optimally grazed pastures.