Pretreatment with DCA intraperitoneally, but not CA, alleviated S. aureus-induced mastitis, as evidenced by DCA improving mammary injury (Fig. 2A, B), mammary S. aureus burden (Fig. 2C), proinflammatory markers including TNF-α, IL-1β and IL-6 and MPO activity (Fig. 2D–G) compared with that of the S. aureus group. Here, MPO is linked to mastitis.