Economic premiums associated with Mycobacterium avium ssp. paratuberculosis-negative replacement purchases in major dairy-producing regions

Johne's disease, or paratuberculosis, is an infectious disorder of the intestines that can affect domestic and wild ruminants that is caused by an infection with Mycobacterium avium ssp. paratuberculosis (MAP). Although the economic losses due to Johne's disease in dairy cattle herds and the benefits and costs of various potential control practices have been estimated before, little is known about the economic value of purchasing MAP-negative dairy replacements in ma-jor dairy-producing regions. This study used Markov Chain Monte Carlo simulation techniques to compare 2 sets of MAP-negative and MAP-positive herds across a comprehensive selection of regions: herds purchasing MAP-negative replacement animals and herds purchas-ing replacement animals with unknown MAP infection status. The economic benefits per MAP-negative re-placement purchased were then estimated over a 10-yr horizon, and the additional value of MAP-negative replacements when compared with unknown status replacements were calculated as a percentage premium of the average aggregated dairy replacement price in each region. An average benefit of US$76 per MAP-negative replacement purchase was estimated in major dairy-producing regions, equivalent to a premium of 13%, with higher premiums in regions characterized by below-average replacement prices and on-average farm-gate prices. It was also estimated that the greatest benefits from MAP-negative replacement purchases are associated with MAP-negative herds that successfully remain uninfected.