Abstract

New Zealand coarse-woolled sheep farmers today barely recover the costs of shearing. One option is to introduce a self-shedding breed such as the Wiltshire. A strategy to transition to a Wiltshire flock is to cross a ewe flock with Wiltshire rams and in subsequent years backcross with Wiltshire rams. The first year of a long-term study found the performance of first cross Wiltshire progeny were not different to the base Romney flock in terms of birth weight and growth to weaning. The ewe lambs from this first breeding were then bred as ewe lambs to Wiltshire rams in late April 2021 to generate ¾ Wiltshire lambs. There were no differences (P>0.05) in fertility or fecundity between the ½ Wiltshire cross or Romney ewe lambs. There were no differences in birth, docking or weaning weight with the exception that single-born ¾ Wiltshire cross lambs had higher growth (P<0.05) from birth to weaning than their Romney counterparts. This effect was not (P>0.05) observed in twin lambs. Combined these results indicate to date that there are no negative impacts of introducing Wiltshire rams to a mixed-age Romney ewe flock in relation to ewe performance to 15 months of age and the performance of their ¾ progeny to weaning.

RA, Corner-Thomas, AL Ridler, PR Kenyon, CJ Andrews, DL Burnham, HT Blair, and ST Morris

New Zealand Journal of Animal Science and Production, Volume 82, Online, 45-49, 2022