Investigation of Coxiella burnetii distribution in a Scottish dairy cattle herd with history of stillbirths

Background: Coxiella burnetii is a bacterial pathogen that can cause abortion and reproductive disease in livestock. In the UK, C. burnetii affects many dairy cattle herds, although the infection dynamics are poorly understood. Our study was performed to investigate infection patterns within a dairy cattle herd in Scotland that had experienced stillbirths attributed to C. burnetii infection. Methods: Different management groups within the affected herd were sampled. Serology and qPCR testing of vaginal swabs were performed to investigate infection status. Regression analyses were performed to evaluate associations between diagnostic results and variables describing calving status and farm site. Results: C. burnetii infection was detected in all management groups within the herd. The highest seroprevalence was detected in pre‐calving heifers (78.6%) and the highest bacterial loads were detected in post‐calving animals. Limitations: These data represent a sample from one farm and testing for a single pathogen shedding route, which limits the generalizability of our findings. Conclusions: C. burnetii infection is widespread within this affected herd. Marked differences were observed between the management groups, which may be explained by variables including pregnancy stage or environmental factors. Further work is needed to understand the implications of these results for the wider UK dairy sector.