In this study, MDA concentrations were found to be increased in the ‎serum, milk and tissue ‎of rats ‎with mastitis compared to the control group, ‎while decrease of GPx, SOD and CAT ‎activities were ‎observed.‎ These changes ‎were coupled to the increase of MDA concentrations ‎confirmed the occurrence of ‎an ‎oxidative stress during mastitis caused by LPS. Here, CAT is linked to mastitis.