Determining the cause of mastitis is important because not all cases of mastitis benefit from antibiotic therapy. For instance, Gram positive bacteria, such as Staph aureus and coagulase negative behave differently in the cow and have different responses to therapy. Being able to identify between the two can help us make appropriate treatment decisions for managing mastitis in our herds. One way to do that is through on farm culturing. In this episode, Dr. Pamela Ruegg teaches us how to identify Staphylococcus species on our cultured media plates whether we are using bi-, tri- or quad plates.