The role of diagnostic microbiology in mastitis control programs.

There are a number of important issues for the dairy practitioner to consider in designing the most appropriate mastitis microbiological service for his or her clients. These include the decision to use enhancement tools or selective agars to optimize sensitivity and specificity. The service should include a monthly BTC service that monitors for the important contagious mastitis organisms: S aureus, S agalactia, and Mycoplasma. At the cow level, a zero tolerance program to protect healthy cows from exposure to contagious mastitis will require a routine culture service to monitor for these pathogens in new herd additions, clinical cases, and all fresh cows and heifers. A wide variety of additional benefits for maintaining good udder health and the production of quality milk can come from a more comprehensive diagnostic service that looks at both individual cow and bulk tank milk. Finally, more practitioners can help their clients economically by implementation of an on-farm TNT culture service and significantly reducing the use of intramammary therapy.