A new resilience test for merino sheep is using hereditary markers to help producers identify which animals are better able to cope with stressors in their environment.
The genomic tool, known as ImmuneDEX, measures a resilience trait called immune competencies, by comparing how individual sheep respond to a standard vaccine challenge, where all animals receive the same vaccine to assess differences in their immune response.
It has been developed through a collaboration between CSIRO, Australia’s national science agency, in collaboration with Neogen, the Animal Genetics and Breeding Unit (AGBU) and Sheep Genetics, a national genetic information and evaluation service operated by Meat & Livestock Australia (MLA).
The work builds on previous projects in Merino sheep, supported by Australian Wool Innovation (AWI), examining the genetics of traits related to resilience and immune competence.
CSIRO Senior Scientist Mrs Amy Bell said the work examines an aspect of animal performance that has been difficult to measure in the past.
“We’ve been asking animals to be as productive as possible, but we haven’t always understood why some cope better with challenges than others,” Bell said.
“Sheep face a range of stressors from disease to climate and flock management, and this work gives us a way to measure how well they respond to aspects of those challenges.”
Researchers assessed immune responses in a large population of Merino sheep, enabling them to build a clearer picture of how resilience varies between individual animals.
The research showed that some sheep consistently responded better than others, and that this ability had a genetic component, meaning it could be improved over time through selective breeding.
The findings showed that this measure of resilience is linked to animal health but has little to no correlation to key production traits relating to wool characteristics and bodyweight.
Bell said this allows a component of resilience to be considered alongside existing breeding priorities.
“Selecting for productivity doesn’t necessarily mean you’re selecting animals that cope well with stressors,” she said.
“We now know that this trait is heritable and has favourable genetic relationships with animal health traits.”
The project is now entering its second phase, allowing producers to access and use ImmuneDEX as part of their breeding programs.
Amy Bell will be presenting her research at the LambEx 2026 conference at the Adelaide Convention Centre, during a breakfast panel discussion on Wednesday 8 July 2026 from 7:15am.
