Conclusions
Troubleshooting herds incorporates various mixtures of science and art. The reliance on intuition (and possible liability) can be minimized by analytically evaluating factual data. The single most important aspect of competently troubleshooting a mastitis herd is to correctly identify the causative microbial agents. Many logical recommendations can be made to most herds without the aid of microbial culturing, but the risk of error is much greater to cause the problem to persist or even exacerbate. Incorporating culture results, the current knowledge of microbial ecology and epidemiology of mastitis pathogens, and with the history of management changes will enable those troubleshooting a herd to provide more useful information to the producer to correct management deficiencies.