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.