Efficacy of feeding plasma-derived commercial colostrum replacer for the prevention of transmission of Mycobacterium avium subsp paratuberculosis in Holstein calves.

Objective—To estimate the relative risk of paratuberculosis (Johne's disease [JD]) in calves fed a plasma-derived colostrum-replacement (CR) product versus raw bovine maternal colostrum (MC). Study Design—Randomized controlled clinical trial. Animals—497 heifer calves born in 12 JD-endemic commercial Holstein dairy farms located in Minnesota and Wisconsin. Procedures—Every calf was separated from its dam within 30 to 60 minutes after birth and systematically assigned to be fed raw bovine MC (control group, n = 261 calves) or CR (treatment group, 236 calves). The calves were monitored to adulthood and tested for Mycobacterium avium subsp paratuberculosis (MAP) infection by use of an ELISA to detect serum antibodies against MAP and bacterial culture for MAP in feces at approximately 30, 42, and 54 months of age. Weibull regression models were used to evaluate the effect of feeding CR (vs raw bovine MC) on the risk of developing JD infection. Results—Calves fed CR at birth were less likely (hazard ratio = 0....