Selecting for Worm Resistance in Low-Challenge Systems with Swabtec

Head Shepherd

Head Shepherd
Selecting for Worm Resistance in Low-Challenge Systems with Swabtec
Dec 21, 2025 Season 2025 Episode 263
Mark Ferguson

What if measuring worm resistance didn't require high parasite burdens and ALSO delivered double the heritability of egg counts?

Sarah Preston, Lecturer at Federation University and cofounder of Swabtec, explains the development of their saliva-based test designed to measure immune responses to gastrointestinal worms in sheep, allowing resistance to be assessed without relying on high worm egg counts.

She and Mark discuss why egg counts often fail to reflect adult worm burden, particularly in mixed infections and with species that regulate egg production, and how this affects breeding and management decisions in well-managed, low challenge systems.

They also discuss where they are with the development and validation of Swabtec. They are currently working to validate the test across breeds and environments and are planning to develop breeding values as the data builds. The test has been found to have a heritability of 0.4 compared to the WEC of 0.2 meaning flock improvements based on insights and data from Swabtec can occur twice as fast!

Find out more below:

https://swabtec.com/

Head Shepherd is brought to you by neXtgen Agri International Limited. We help livestock farmers get the most out of the genetics they farm with. Get in touch with us if you would like to hear more about how we can help you do what you do best: info@nextgenagri.com.

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