THE HERD HEALTH APPROACH OF A HIGH BULK M ILK SOMATIC-CELL COUNT CAUSED BY STREPTOCOCCUS-AGALACTIAE

The herd health approach for dairy herds with a high bulk milk somatic cell count, in which Streptococcus agalactiae plays a major role, was evaluated. After introduction of the standard mastitis prevention pro gramme, all quarters of infected cows were treated during lactation. I n three of the four herds investigated, the bulk milk somatic cell cou nt dropped below the limit of 400,000 cells/ml for a long period of ti me. The herd in which there were many infections with Staphylococcus a ureus and Streptococcus agalactine was an exception. The management, s omatic cell count, and prevalence of subclinical mastitis in the diffe rent herds is disscussed. It is concluded that for infection with Stre ptococcus agalactiae at the herd level, treatment during lactation can be an effective method to lower the bulk milk somatic cell count. In essence, however, the approach to the problem lies in the standard mas titis prevention programme.