Economic impacts of Salmonella Dublin in dairy farms: Panel evidence from Denmark

Salmonella Dublin (SDB) is a highly infectious, multidrug-resistant strain of Salmonella prevalent in cattle, where it often remains asymptomatic but can lead to severe illness and high mortality rates in humans. Despite the significant public health challenges, its asymptomatic nature in cattle discourages farmers from implementing control measures, underscoring the need to evaluate the link between SDB and farm economic outcomes. This paper presents the first comprehensive empirical estimates of the economic impact of SDB infections on dairy farms, based on a unique panel dataset of registered Salmonella antibodies measured in Optical Density Counts (ODC) from milk deliveries across all Danish dairy farms. Using high-dimensional fixed effects regression that includes asymptomatic herds, we find that SDB is significantly associated with reductions in productivity, lower milk yield, higher calf mortality, and increased operational costs. Even small positive ODC levels are associated with reduced milk yield, although the losses diminish as ODC levels rise. Moreover, small increases in calf mortality are correlated with higher ODC levels. The study also shows that SDB infections are associated with a substantial increase in veterinary, medical, and labor costs related to biosecurity measures, compared to farms with zero ODC levels. These findings emphasize the need to focus on prevention and create stronger incentives to encourage farmer compliance with SDB eradication efforts.