Risk factors for intramammary infection in meat- and pelt producing ewes with clinically healthy udders

•Ewe risk factors for IMI: Older ewes, ewes with >2 lambs, and hard milked ewes had higher risk for IMI.•Herd risk factors for IMI: Ewes in herds of moderate size, with hay as a bedding and with less cases of CM had higher risk of IMI.•Most risk factors differed between weaning and lambing. Mastitis is prevalent both in milk- and meat- and pelt producing sheep flocks and is an important disease with substantial effects on economy, animal welfare and antibiotic use, and in dairy flocks also on milk quality and safety. In meat- and pelt producing flocks, the farmers are mainly concerned by clinical mastitis (CM), and most cases of subclinical mastitis (SCM) are not detected and not dealt with, posing a risk for poor udder health in the flock. Studies on risk factors for SCM and/or intramammary infections (IMI) in meat producing flocks are scarce and specific risk factors for weaning and lambing are absent. The aim of this study was therefore to investigate associations between risk factors, at ewe and flock level, for IMI after lambing and at weaning in Swedish meat- and pelt producing ewes with clinically healthy udders. Twenty-two meat- and pelt producing flocks from different parts of Sweden were enrolled in this cross-sectional study. Udder half milk samples were collected at weaning and after lambing from ewes with clinically healthy udders, for bacteriological investigations. Data on ewe and flock level risk factors were recorded. In total, 753 ewes were sampled at least once, and the overall IMI prevalence was 22.5 %. Older ewes, ewes with three or more lambs, ewes that were hard to milk when collecting a milk sample, ewes in moderate size flocks, in flocks with hay as a bedding material and in flocks with less cases of CM had higher risk of IMI. Most of the risk factors associated with IMI in this study differed between weaning and lambing. This study has provided us with novel knowledge on how different factors influence udder health of meat- and pelt producing ewes.