A study published online on 9 October 2026 in the Journal of Dairy Science estimates the true herd-level prevalence and spatial distribution of Salmonella Dublin-seropositive dairy herds in Alberta, Canada.

The research team, led by first author Waseem Shaukat and senior investigators including Herman W. Barkema, Jeroen De Buck and David K. Kelton of the University of Calgary, applied Bayesian statistical methods to herd-level serological data. Co-authors also included Diego B. Nobrega, Abdul Rehman, Jessie van Heumen, Rebecca Roos, Marlinde de Pater, Chanda Liaqat, David C. Hall, Guillaume Lhermie and John P. Kastelic.

Why does this study matter at the farm gate?

Salmonella Dublin is a host-adapted serovar in cattle that causes respiratory disease, septicemia and abortion in calves and adult cows, and infected herds can carry the organism without showing obvious clinical signs. Because apparent prevalence from antibody testing understates or overstates true exposure depending on test accuracy, the authors used Bayesian estimation to adjust for diagnostic sensitivity and specificity.

The approach produces an estimate of true herd-level prevalence rather than a raw count of positive test results. It also maps where seropositive herds cluster spatially across Alberta, information producers and veterinarians can use to target biosecurity and surveillance.

The study addresses a recognized gap: Canadian dairy producers and their veterinarians have lacked provincial-scale, corrected estimates of Salmonella Dublin herd exposure to guide control decisions.

What are the practical implications?

For dairy practitioners in Alberta and neighboring provinces, the findings provide a baseline against which future changes in herd exposure can be measured. Spatial distribution data can direct on-farm risk assessments toward regions where seropositive herds concentrate.

Salmonella Dublin also carries a public-health dimension. The bacterium can infect people through contact with infected animals or contaminated milk, and asymptomatic carrier animals sustain herd-level infection. Food-animal veterinarians therefore hold a central role in both animal health and zoonotic risk management.

The study's authors state that understanding true prevalence and geographic clustering is a prerequisite for designing cost-effective control programs at the provincial level.

What changes for surveillance?

Bulk-tank milk serology is the routine screening tool for Salmonella Dublin in dairy populations, and Bayesian adjustment of such data allows regulators and industry groups to estimate exposure without testing every animal. The method demonstrated in this Alberta study could transfer to other jurisdictions and other production diseases where diagnostic test performance is imperfect.

Peer-reviewed estimates of true prevalence also support decisions on voluntary versus mandatory control measures, an issue dairy industry organizations in Canada have debated as Salmonella Dublin has spread in North America.

The full methodology, herd-level estimates and spatial maps appear in the Journal of Dairy Science, available online since 9 October 2026.

The study gives Alberta's dairy sector its first province-wide, diagnostically corrected picture of Salmonella Dublin herd exposure, and it establishes the baseline future surveillance programs will need to demonstrate progress.