Serina Hancock

Improving ewe reproductive performance remains a priority for the Australian sheep industry. Here we present a protocol for veterinary practitioners to investigate cases of poor reproductive performance. The proposed methodology can be readily adapted to account for resources available and risk factors specific to the farm in question. This protocol will allow practitioners to determine the (a) timing and (b) likely causes of foetal/lamb loss to inform strategies targeted at improving reproductive performance.

The Merino Lifetime Productivity project is evaluating the lifetime productivity of the ewe progeny of industry sires at five sites around Australia. Additional work at the Pingelly site is evaluating the productivity of the wether progeny. Liveweight, carcase traits and wool production data for wether progeny born in 2016 and 2017 have been collected. This paper presents a preliminary analysis of the value of production of the 2016 and 2017 drop wethers at yearling and adult age. The difference in value of production to 18-22 months of age between the top and bottom ranking sire groups was approximately $50 per head, excluding differences in mortality between sire groups. In future analyses the wether data will be compared to the productivity of the ewes as well as combined with ewe data to calculate flock profitability so comparisons can be drawn between sires in feed intake and whole-body energy.

Suboptimal reproductive performance of maiden ewes impacts sheep enterprise productivity, but the extent and causes of the poorer reproductive performance of maiden ewes on Australian sheep farms are not well understood. Here we show the reproductive performance of maiden ewes relative to their multiparous counterparts on the same farms across Australia using a cohort survey. Data were collated for 79 farms (413,702 ewes) across major sheep producing regions in Australia. There was a 58% difference in marking rate for non-Merino maiden ewe lambs compared to multiparous ewes, and this was attributable to 50% difference in reproductive rate and 16% difference in lamb survival. For maiden Merino hogget ewes, there was a 22% difference in marking rate compared to mature multiparous ewes and this was attributable to 24% difference in reproductive rate and 3% difference for lamb survival. Reproductive performance (reproductive rate, lamb survival and marking rate) in maiden Merino hoggets was correlated with that for mature ewes on the same farm, but these correlations were weak or nonexistent for ewe lambs. Our findings show that veterinarians can add value to sheep enterprises by working with managers to assess reproductive rate and lamb survival in different ewe cohorts and compare current performance against industry benchmarks. This will inform interventions targeted to ewe age groups and stages of reproductive cycle with greatest opportunity to deliver improvement in farm profitability and animal welfare.