Lamb mortalities are estimated to cost the Australian sheep industry $1B per year (Kubeil 2017; Young et al. 2014). Improving lamb survival is therefore an important driver of the productivity and profitability of sheep enterprises. Reducing lamb loss is not only important for rebuilding the national sheep flock but also to demonstrate improvements in animal welfare and thus meet consumer needs and maintain market access. Approximately 30% of lambs die between pregnancy scanning and marking (Hinch and Brien 2014; Oldham et al. 2011). The survival of Merino lambs is also often 5% to 10% lower than non- Merinos (Allworth et al. 2017; Lockwood et al. 2019). Optimising the nutrition of single- and twin-bearing ewes is vital for improving lamb survival. Ewes typically require supplementary feeding when lambing in autumn and when pasture availability is limited when lambing during winter/spring. However, subjective evidence suggests that supplementary feeding ewes at lambing may have a negative effect on ewe-lamb behaviour leading to mismothering and poorer lamb survival (Morcombe et al. 1988; Advantage
Feeders). Conflicting opinions exist as to whether the use of self-feeders or trail feeding creates less mismothering and thus achieves greater lamb survival. This project will investigate methods of supplementary feeding ewes at lambing on ewe behaviour and lamb survival. This research will contribute to the development of guidelines for producers for supplementary feeding strategies during lambing to optimise lamb survival.