New genomic tool ImmuneDEX enhances resilience measurement in Merino sheep

A groundbreaking genomic tool known as ImmuneDEX has been developed to measure resilience in Merino sheep. This innovative test utilizes hereditary markers to help producers identify sheep that can better cope with environmental stressors. The research, conducted by CSIRO in collaboration with Neogen, the Animal Genetics and Breeding Unit (AGBU), and Sheep Genetics, marks a significant advancement in animal breeding.

Understanding the ImmuneDEX Tool

The ImmuneDEX tool assesses a specific resilience trait called immune competencies by comparing the immune responses of individual Merino sheep to a standardized vaccine challenge. All participating sheep receive the same vaccine, allowing researchers to evaluate the differences in immune responses across the population.

This tool has evolved from previous projects focusing on the genetics of resilience and immune competence, supported by Australian Wool Innovation (AWI). This collaboration aims to provide a deeper understanding of how these traits can be measured and improved over time.

Impact on Sheep Breeding Practices

According to CSIRO Senior Scientist Amy Bell, this research addresses a critical gap in understanding animal performance. “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 stated. “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.”

The research involved a large population of Merino sheep, enabling scientists to identify genetic variations in resilience. The findings indicate that certain sheep consistently exhibit superior immune responses, suggesting a heritable component that can be enhanced through selective breeding.

Linking Resilience to Animal Health

The study revealed that the measure of resilience is closely associated with animal health but does not correlate significantly with key production traits such as wool characteristics and body weight. Bell emphasized the importance of integrating resilience into breeding priorities: “Selecting for productivity doesn’t necessarily mean you’re selecting animals that cope well with stressors.”

The project is now entering its second phase, allowing producers to incorporate ImmuneDEX into their breeding programs. Amy Bell will present her findings at the LambEx 2026 conference, highlighting the potential of this genomic tool to revolutionize sheep breeding practices.