Evaluation of frequent milkout for treatment of cows with experimentally induced Escherichia coil mastitis.

OBJECTIVE To evaluate the effect of frequent milkout (FMO) on the outcome of experimentally induced Escherichia coli mastitis in cows. DESIGN Randomized complete block study. ANIMALS 16 Holstein dairy cows. PROCEDURE Cows were randomly assigned to 1 of 4 groups and were either not infected and not treated (NI-NT), experimentally infected with E coli and not treated (EC-NT), not infected and FMO (NI-FMO), or experimentally infected with E coli and FMO (EC-FMO). The infected quarter in cows in FMO groups was milked out every 4 hours from 16 to 36 hours and every 6 hours from 36 to 84 hours after challenge, with the aid of oxytocin administration. Somatic cell counts (SCC); times to bacterial, clinical, and systemic cures; and serum concentrations of a-lactalbumin were determined. RESULTS Use of FMO did not appear to affect SCC. For EC-NT and EC-FMO groups, mean bacterial cure times were 203 and 159 hours, clinical cure times were 276 and 360 hours, and systemic cure times were 144 and 159 hours, respectively; these times were not significantly different. Concentrations of a-lactalbumin were significantly increased in the EC-NT group at 12 hours and in the NI-FMO group at 36 and 60 hours after challenge, compared with values of cows in other treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE Compared with results in control cows, FMO does not appear to be an efficacious treatment for experimentally induced moderate to severe E coli mastitis.