Staphylococcus epidermidis is a less common cause of mastitis in dairy cows. It naturally occurs on the human skin and hands of milkmaids are the source of contamination of both milking machines and the mammary gland skin of the dairy cows.
Staphylococcus epidermidis penetrates the udder through the teat canal. Often, the infection is spontaneously eliminated and thus these bacteria do not always cause mastitis. If mastitis occurs, then it is mild.