Bovine mammalian gland has biopotential in therapeutic protein production and could be used as a model in further lactation researches. In this study, we have isolated bovine mammary gland-derived epithelial cells (BMECs) from Korean Holstein dairy cattle and themselves show differential dynamic ability in in-vitro culture. BMECs enables to form lobulo-alveolar structure, express milk production related gene. Functional studies indicated that BMECs secret exogeneous antibacterial fragment-Bovine Lactoferricin B (bLfcin-B), which is inserted in PiggyBac system, and this bioactive fragment inhibits the growths of Escherichia coli and Staphylococcus aureus. These data demonstrated that BMECs open new scope in either bioactive fragment, heading to prevent the spread of mastitis or post-mastitis damage in dairy graze and could be an ideal bioreactor for antibacterial proteins.