Risk factors for Salmonella Dublin on dairy farms in Ontario, Canada

Salmonella Dublin (S. Dublin) is an emerging pathogen on dairy farms in Canada. In Ontario, S. has been increasingly isolated from diagnostic laboratory samples. The objective of this observational cross-sectional study was to identify management practices associated with herd positivity for Dublin. A convenience sample 100 visited Canada April August 2022. Farms were once collect blood samples 20 heifers between 4 and 24 mo old, bulk tank milk, administer in-person questionnaire practices. An additional milk collected before the visit by transporters. All serum underwent ELISA testing determine (≥35% percent ELISA). Of 1,990 sampled, 44 (2.2%) animals seropositive At least one heifer identified 24% participating farms. Based during both sampling periods, 4% positive Overall, visited, 25% classified as positive, meaning at or interpreted positive. multivariable logistic regression model 5 factors herd-level Specifically, introducing purchased within last 2 years increased likelihood that (odds ratio (OR) = 4.6). had animal leave premises a cattle show, embryo collection center, loan another farm return also higher risk (OR 4.9). removed manure surface bedding calving pens twice per month after every greater than less frequently 8.5). added material areas weekly lower compared 0.1). addition, kept 3 cows pen area Test among Ontario sampled high, producers should consider avoiding are infection.