Epidemiological insights into the prevalence of, and risk factors for, Eimeria species in Australian dairy goats

This cross-sectional study investigated the prevalence, species composition and risk factors for Eimeria infections in Australian dairy goats. A total of 1,188 goat faecal samples was collected from 71 herds between November 2023 and July 2024. Oocysts per gram (OPG) of faeces were quantified using the modified McMaster technique, and Eimeria species were identified morphologically. The animal-level prevalence of Eimeria was adjusted for the effect of herd, and risk factors were analysed using multivariable mixed-effects logistic regression models. The adjusted animal-level prevalence of Eimeria species was 71% (95% confidence intervals (CI) 63% to 77%), and a herd-level prevalence was 97% (95% CI 93% to 100%). The highest adjusted prevalence of Eimeria species (86%, 95% CI 80% to 91%) and median OPG (240; Q1:30, Q3:1,500) were identified in kids. Prevalence and oocyst shedding varied significantly by climatic zones, with the winter rainfall zone presenting the highest adjusted prevalence (75%, 95% CI 65% to 84%) and median OPG (60, Q1: 0, Q3: 360). Nine Eimeria species were identified, with E. arloingi (100%), E. ninakohlyakimovae (94%) and E. alijevi (91%) being most prevalent. Significant risk factors included age, sex, climatic zone, stocking rate, bedding type and bedding replacement frequency. These findings demonstrate that Eimeria infection is highly endemic and strongly clustered within Australian dairy goat herds, particularly in young animals, and highlight the importance of age-targeted and management-based control strategies. Improved husbandry practices may reduce environmental contamination and mitigate the production impact of caprine coccidiosis. • A total of 1,188 dairy goats from 71 herds across six Australian states was tested. • Adjusted animal-level prevalence of Eimeria spp. was 71% (95% CI: 63–77%). • Herd-level prevalence was 97% (95% CI: 93–100%). • Significant risk factors were age, sex, climatic zone, stocking rate, bedding type and replacement frequency. • The most abundant Eimeria species were E. arloingi , E. ninakohlyakimovae and E. alijevi .