Culling Cows
Cows with a very high SCC that do not respond to antibiotic therapy or that have chronic mastitis may have to be culled from the herd. Usually, cows with high SCC have mastitis that is caused by contagious bacteria, primarily Staphylococcus aureus but also Streptococcus agalactiae. The most common source of contagious bacteria is other infected cows; whereas, environmental pathogens are most commonly isolated from recently calved and dry cows. These bacteria, especially Staphylococcus aureus, often do not respond to routine antibiotics and should be cultured to determine a more appropriate antibiotic. If the cow then does not decrease in SCC after more extensive treatment, she should be culled.