Pregnancy loss caused by Chlamydia psittaci represents a significant challenge for the Australian Thoroughbred breeding industry, with implications for both equine welfare and human health. This project advanced industry capability by improving understanding of the pathology of C. psittaci associated pregnancy loss and developing clearer diagnostic criteria to support consistent case identification. The research also delivered rapid, species-specific diagnostic options to enable earlier detection of C. psittaci and EHV1 in clinical settings. These outcomes support faster decision making, improved disease management and reduced risk to industry participants.