Mastitis is an important disease of dairy cattle. The disease has been around for a long time. Still, in the last decades, major changes in the understanding of the epidemiology and pathobiology of the disease have occurred. In this paper, three case studies are discussed, in which a number of these major changes were used to improve the understanding of bovine mastitis in those herds. The results of both the literature review and the case studies are discussed and summarized in conclusions.