Liveweight gain per head and per ha throughout the year of lambs grazing conventional pastures and those that switch from grass to clover

Abstract

Intensive lamb finishing requires a consistent supply of high quality forage throughout the year to regularly finish lambs. Per head and per ha liveweight gain of weaned lambs was compared in 13 batches of lambs on replicated irrigated farmlets for 2.5 years from conventional mixed tetraploid perennial ryegrasswhite clover pastures (Conv) and pastures that were pure white clover for spring and summer and switched to overdrilled Italian ryegrass for the winter (Switch). Seasonal differences in stocking rate (lambs/ha), liveweight gain per head and per ha were significant (P<0.05). Average daily liveweight gain/ha was significantly higher (6.01 versus 5.66 kg/ha/day for Switch and Conv, respectively, but the total grazing days were slightly lower on the Switch farmlets resulting in similar annualised liveweight gain per ha (1 800 kg) and net carcass weight (800 kg/ha) on both pasture treatments. The farmlets apparently utilised 10 000 kg DM/ha/yr of the 16 000 kg DM accumulated.