Observational study to determine the proportion of first milking colostrum from Scottish dairy herds positive for Mycoplasmopsis bovis

Background: Mycoplasmopsis bovis causes a range of clinical conditions, including mastitis, arthritis, otitis and bronchopneumonia. Proposed transmission routes include semen, milk, colostrum, aerosol, nose-to-nose contact and fomite spread. Methods: Seventy-nine composite colostrum samples were collected directly from cows’ teats on 10 farms in the Dumfries and Galloway region of Scotland. The samples were transported on ice to the laboratories at Scotland's Rural College, where they underwent M. bovis polymerase chain reaction testing. Results: Of the 79 samples tested, 78 tested negative for the presence of M. bovis DNA and one returned an inconclusive result. Limitations: Samples were not randomly selected but were instead convenience samples from a cohort of progressive farms. As such, the findings may not be representative of the wider population of Scottish dairy herds. Conclusion: Results from this work suggest that colostrum as a transmission route for M. bovis is less important than other routes, such as nose-to-nose contact or fomite spread.