Merino ewe mortality – prevalence, causes and mitigation strategies

This four-year project commenced in 2023 and involves Merino producers, vets, researchers and advisors who are collaborating to investigate Merino ewe mortality on a national scale.  

Lifting ewe survival rates will positively impact animal welfare and productivity outcomes along with lamb survival rates; all of which are priorities for the sheep industry.

This four-year project aims to understand the prevalence and causes of Merino ewe mortality. Maximising ewe survival during lambing requires an understanding of why ewes die and how management practices can prevent these deaths. The project team are exploring a range of intervention strategies to determine the most practical and cost-effective strategies Merino producers can implement on farm to maximise ewe survival.

The first stage of the project involved a comprehensive literature review and online survey that gathered insights from 160 Merino producers around the country about the incidence of Merino ewe losses in their sheep enterprises over a 12-month period. The literature review was published in the Australian Veterinary Journal (DOI: 10.1111/avj.13430). An infographic with the results of the industry survey can be accessed here.

Phase 2 of the project was carried out during 2024. Seven producer groups were formed ahead of the lambing season in key Merino production regions across Australia - southern, central and northern NSW, Victoria, South Australia, and the northern and central wheatbelt of WA. Each group was supported by a vet from the project team.

The focus of data collection during the 2024 lambing season was on ‘business as usual’, management strategies, whereby producers were asked to record lambing data in a farm diary from the moment ewes were set stocked for lambing through to lamb marking, without changing their management practices.

Vets performed post-mortems on ewes from a selection of participating properties in each group to identify the causes of death. The producer-recorded and veterinary-recorded data collected during this phase, together with the literature review and industry survey, informed the selection of intervention strategies trialled on farm during the 2025 lambing season.

During the 2025 lambing season, a selection of producers in each group implemented trials and collected data. The selected interventions included:

• calcium supplementation
• vitamin A, D and E supplementation
• vitamin E supplementation in containment
• condition scoring for differential management.

Data is currently being analysed for the 2025 lambing season. Economic data is being collected to aid in cost:benefit analyses for the various intervention strategies.

Key findings from the project will be presented through seven case studies and will be integrated into existing extension and adoption programs.

Project activity is conducted under Human and Animal Ethics licences where required.

This project is funded by MLA and AWI.