BACKGROUND: Mastitis has a negative effect on sheep health and welfare and causes significant economic losses to farmers. This study aimed to estimate the incidence of clinical mastitis in meat-producing sheep flocks in the UK and the Republic of Ireland and describe its variation between farming systems, countries and management practices. METHODS: An online questionnaire was distributed to sheep farmers recruited through veterinary practices and industry organisations. The survey was available between September 2022 and April 2023. RESULTS: A total of 103 responses were collected. Of these, 53.4% were from lowland farmers, 49.5% were from farmers practising indoor lambing and 68% were from farmers with commercial flocks. The mean perceived incidence of clinical mastitis was 3.7 cases per 100 ewes per year (95% confidence interval: 3.0-4.4). Flock size was negatively correlated with the perceived incidence of clinical mastitis
however, country, farming system, flock type and lambing type did not significantly influence the perceived incidence of clinical mastitis. Acute clinical mastitis was more frequently identified in early and late lactation, while chronic clinical mastitis was more frequent at lambing, weaning and postweaning. More medical treatments were used for acute clinical mastitis cases than for chronic clinical mastitis cases. LIMITATIONS: The main limitations of the study were the relatively low number of responses received and the potential selection bias. CONCLUSION: The perceived incidence of clinical mastitis in meat-producing sheep flocks in the UK and the Republic of Ireland is 3.7 cases per 100 ewes per year, regardless of farming system, flock type, lambing type and country.