We are happy to share the completion of our research project on paratuberculosis (Johne's disease) in Swiss dairy herds, with the results now published in a scientific paper. The project was led by the Clinic for Ruminants at the Vetsuisse Faculty of the University of Bern, with SAFOSO responsible for performing the epidemiological analyses and statistical assessment of risk factors.
Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic bacterial infection in dairy cows that affects the small intestine, causing weight loss, diarrhea, and reduced milk production. Until today, the true prevalence and risk factors in Swiss dairy herds remained largely unknown.
This project aimed to conduct a representative serological study to assess the prevalence of antibodies against MAP in dairy cows. Additionally, we sought to identify the risk factors associated with the introduction and spread of paratuberculosis within herds, which were investigated through a comprehensive questionnaire. The study involved 10,063 serum samples collected from cows over 12 months of age across 171 dairy farms in Switzerland. Using a commercial ELISA test, we determined a between-herd seroprevalence of 3.6% (95% CI,0.96-8.4%). While the within-herd seroprevalence ranged from 2.3% to 5.5%, the median was 3.6% in the nine farms testing positive for MAP.
We also identified several risk factors associated with seropositive herds. Larger herd sizes and the common grazing of lactating cows with cows from other herds were associated with a higher likelihood of seropositive status. Conversely, heifers sharing alpine pastures with dairy cattle from other herds were associated with a reduced probability of the herd testing seropositive.
Despite these findings, reliable identification of significant risk factors for MAP spread within herds proved challenging due to low seroprevalence and the limited sensitivity of the ELISA test, particularly in small herds.
For more insight access the publication here: Link
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