Isolation of Mycoplasma bovis from bulk milk

The prevalence of mycoplasma in Vermont dairy farms was determined by two surveys conducted in March 1983 and January 1984. Bulk tank milk samples representing 74% and 62% of the herds respectively were cultured. Mycoplasma bovis was detected in 3 of the 2,346 bulk samples collected in the initial survey. The infection rate was 1.3 herds per thousand (95% confidence interval: 0.6-2.0 herds per thousand). No positive cultures were obtained in the second survey.