Importance and epidemiology of mastitis in the Australian sheep flock

Summary

​This project investigated the impact of mastitis on eight meat and wool sheep properties in Australia as there is little published on this disease in Australian sheep. Over 5,200 Merino, Poll Dorset and maternal ewes had milk collected at weaning, along with clinical mastitis samples collected from other flocks. The presence of mastitis at weaning reduced lamb growth and impacted ewe production and welfare. The most common causes of clinical mastitis were Mannheimia species with coagulase negative Staphylococci the predominant cause of sub-clinical mastitis. Some antibiotic resistance was found in bacteria causing clinical mastitis, in particular to penicillin, but little resistance found in bacteria causing sub-clinical mastitis. A combination of physical selection, milk testing and recording, vaccination and genetics/genomics may improve the welfare and production of meat and wool sheep by reducing the impact of mastitis.