Getting to the bottom of Merino ewe mortality
28 January 2025
Merino producers are working with researchers, vets and consultants on a four-year MLA/Australian Wool Innovation (AWI) project to determine the roots of ewe mortality before, during and after lambing.
The findings from the project will underpin the development of best-practice management resources to help producers optimise ewe survival.
Ewes represent the most productive unit in a flock, and Merino ewes make up about two-thirds of Australia’s breeding ewe flock – optimising their health and survival is critical.
To kickstart the project and get an estimate of the annual ewe mortality rates across a 12-month breeding cycle, a national online survey was circulated to sheep producers across Australia. The key data collected included the following:
- Most producers who responded to the survey scan and manage ewes according to litter size.
- Reported ewe mortality during lambing rates across all enterprises types (i.e. wool, meat and a combination of wool and meat) lie within the industry average of (2–10%).
- Reported ewe mortality rates during lambing for self-replacing Merino flocks, lie below the industry average of (2–10%) at 1.95%.
You can view more of the key data collected in this infographic.
Previous research indicates the method by which mortality is determined can influence variability. Mortality can, for example, be confirmed by counting carcases, or be assumed from the difference in numbers between yardings. Without a carcase, the cause of death is harder to determine with certainty.
The cause of death is divided (generally) into three categories: those occurring before, during or after lambing. A fourth category can be considered – the deaths that occur around the lambing period not directly caused by pregnancy or lambing, but to which ewes can be more susceptible during this time.
The research team is currently working closely with more than 40 commercial Merino businesses across WA, SA, Victoria and NSW during two lambing seasons to delve deeper into ewe deaths on-farm. They are utilising farm diaries and post-mortems to collect and analyse data.
This data, together with the recently conducted industry-wide survey on Merino ewe mortality, will inform practical intervention strategies that will be trialled on-farm during the 2025 lambing season.
