Episode 297 - Johne’s Disease: What We’re Learning From Herd Testing - UMN Extension's The Moos Room

Abstract

In this solo episode, Brad dives deep into Johne’s disease (paratuberculosis), a chronic intestinal illness affecting ruminants, with a particular focus on dairy cattle. Prompted by recent whole-herd milk ELISA testing at the University of Minnesota’s Morris dairy, Brad shares results, trends, and lessons learned from managing Johne’s over the years. Key topics include: Clinical signs and long-term impact of Johne’s on milk production and cow longevity, Interpretation of milk ELISA results and testing protocols, Management decisions around culling, beef breeding, and calf-rearing practices, Surprising trends in calf infection sources—including group housing and dam-rearing, Insights from genetic studies showing heritability of Johne’s susceptibility, and Practical prevention strategies and the importance of annual testing. Whether you're dealing with Johne’s in your own herd or want to improve your disease prevention approach, this episode is packed with data, reflections, and takeaways to help guide on-farm decisions. Resources: Johnes Disease – APHIS (https://www.aphis.usda.gov/livestock-poultry-disease/cattle/johnes), MN DHIA Johnes Testing (https://www.mndhia.org/johnes-testing.html), DHIA Laboratories - Johnes Testing (http://www.stearnsdhialab.com/), Central Star Johnes Testing (https://mycentralstar.com/johnes-testing/)