The economic impact of Johne’s disease (paratuberculosis) in dairy cattle

Date
2021-02-19
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Abstract
Johne’s disease (JD), or paratuberculosis, is an infectious inflammatory disorder of the intestines primarily associated with domestic and wild ruminants including dairy cattle. The disease, caused by an infection with Mycobacterium avium subspecies paratuberculosis (MAP) bacteria, burdens both animals and producers through reduced milk production, premature culling, and reduced salvage values among MAP-infected animals. The main objectives of this thesis were to estimate the economic impact of MAP infection and potential control practices across a comprehensive selection of dairy-producing regions within a single methodological framework. Additional objectives were to estimate the value of JD control to Canadian dairy producers and to what degree there are economic premiums associated with MAP-negative dairy replacements. Using a combination of Markov Chain Monte Carlo (MCMC) simulation methods, regression analysis, and compensating and equivalent variation analysis, the following results were generated: 1) approximately 1% of gross milk revenue, equivalent to CA$43 (US$33) per cow, is lost annually in MAP-infected dairy herds, with those losses primarily driven by reduced production and being higher in regions characterized by above-average farm-gate milk prices and production per cow; 2) vaccination was the most promising type of JD control practice modelled, with dual-effect vaccines (reducing shedding and providing protective immunity) resulting in BCRs between 1.48 and 2.13 in Canada and a break-even period of between 6.17 and 7.61 years; 3) assuming a within-herd prevalence of 10% and a 50% reduction of that prevalence over 10 years, JD control has an estimated annual value of CA$28 per cow for the average Canadian dairy producer; and 4) MAP-negative replacements are associated with an average benefit of CA$96 per purchase in major dairy-producing regions, equivalent to a premium of 13% of aggregated replacement prices.
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Keywords
MAP, Paratuberculosis, Johne's disease, Vaccination, Testing and culling, Control practice, Markov chain, Monte Carlo, Economic analysis
Citation
Rasmussen, P. (2021). The economic impact of Johne’s disease (paratuberculosis) in dairy cattle (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.