Bovine mastitis persists as one of the most important challenges to the dairy industry, estimated to result in annual costs of €20 billion. Streptococcus uberis is a leading cause of bovine mastitis worldwide and in Scotland it is the second most common cause of both clinical and subclinical cases (1). Traditionally, S. uberis has been classified as an ‘environmental’ mastitis pathogen, primarily spreading through indirect means via environmental contamination. However, emerging evidence challenges this model, suggesting that certain strains exhibit contagious transmission characteristics and may be adapted for cow-to-cow transmission. Despite this recognition of contagious spread, there remains a gap in our understanding of the genetic and mechanistic basis of this distinct transmission, and the lack of reliable diagnostic tools for identifying such strains. Addressing these knowledge gaps holds promise for new interventions in bovine mastitis management, potentially reducing the impact of S. uberis on food production, enhancing animal welfare, and reducing the use of antimicrobials.