In this study 713 cows were examined. The animals were from three dairy farms in northern Paraná and the southwest of the State of São Paulo. From these cows, 137 had mastitis. On the three farms, 8 cows (1.12%) with Mycoplasma bovis mastitis were detected. Four were treated with tylosin and oxytetracyclin and three with enrofloxacin. There was no response to the treatments, and these animals were culled during the lactation period. One cow treated with enrofloxacin almost totally recovered milk production, but elimination of M. bovis continued during the lactation, and there was no bacteriological cure. This cow had a normal milk production in the next lactation period, without elimination of M. bovis. Culling of positive animals, the bacteriological study and correct application of preventive practices for contagious mastitis controlled the dissemination of M. bovis to other animals.
Mastitis; dairy cattle; Mycoplasma bovis
