On-farm batch pasteurization destroys Mycobacterium paratuberculosis in waste milk

A recent dairy survey conducted in 1996 by the National Animal Health Monit oring System suggests bet-ci een 20 and 40% of dairy herds in the United St ates have some level of Johne's disease. This figure will continue to incre ase unless producers implement management regimes that will help control th e spread of this disease within their herds. The neonatal calf is the targe t for infection with Mycobacterium paratuberculosis, the causative agent of Johne's disease. Calves become infected via exposure to the bacterium thro ugh contaminated feces, bedding, colostrum, and milk. Shedding of viable M. paratuberculosis has been documented in the colostrum and milk of infected dams. This study evaluated the efficacy of on-farm pasteurization to destr oy M. paratuberculosis in waste milk fed to calves to circumvent this mode of transmission. In three replicate experiment-a, waste milk was experiment ally inoculated with M. paratuberculosis and heated at 65.5 degreesC for 30 min. No viable bacteria were recovered after 28 wk of incubation. These re sults suggest that batch pasteurization of waste milk contaminated with M. paratuberculosis was effective at generating a clean product to feed to you ng calves.