2014 Volume 67 Issue 1 Pages 43-48
This study was an epidemiological analysis of our experience with 68 cases of bovine mycoplasma mastitis outbreaks over the last 22 years in Hokkaido, Japan. Seventy-five percent of these outbreaks occurred during the last five years; therefore, this revealed an increased incidence of mycoplasma mastitis in Hokkaido. The causes of the outbreak of mycoplasma mastitis in the dairy herd seemed to be the external introduction of pregnant heifers, the parturition of primiparous cows, and occurrences of pneumonia. Mycoplasma bovis was the predominant causative agent in large dairy herds, and Mycoplasma californicum was as significant as M. bovis. In other species, it appeared that these pathogens penetrated large herds regularly and subclinically. The proportion of mycoplasma-infected cows by herd size was 3.8%-15.1% (interquartile range). The developmental period was 0.3-4.7 months, and the disease resulted in 2.1%-9.5% of cows being culled in these herds. In larger herds, the developmental period was extended, and many new infections were found while taking measures to control mycoplasma mastitis, but the installation of quarantine pens for mycoplasma-infected cows was effective in controlling the disease.
