Relative performance of Wiltshire and Perendale sheep

Performance data are reported for flocks of Wiltshire and Perendale sheep grazed together for four years on a North Island hill country property (Whatawhata) and for four years on a South Island breeding/finishing property (Winchmore). Wiltshire ewes were lighter than Perendale ewes post-joining at Whatawhata, and at weaning at Winchmore. Greasy fleece weights of the Wiltshire and Perendale yearlings were 0.8 and 2.2 kg respectively, and 0.5 and 3.3 kg respectively for the ewes. As a result of a confounding effect of fibre shedding between day length and date of shearing, Wiltshire ewes exhibited a linear decrease in harvested fleece weight from the yearling stage whereas Perendale ewes showed a curvilinear age effect, with a maximum fleece weight at three to four years of age. Wiltshire ewes had a significantly lower reproductive rate, and lamb survival than Perendale ewes at both locations, with reproductive rate, fertility and litter size increasing significantly following the transfer of the flocks from Whatawhata to Winchmore. While there was no significant difference in the total weight of lambs weaned by the two breeds at each location, the loss in wool production would be compensated by lower shearing and management costs for Wiltshire sheep that shed completely.