Abstract: [Objective] This study aimed to investigate the preventive and therapeutic effects of Chinese herbal medicine extract （CHME） on subclinical mastitis in dairy cows.[Method] Twenty-four dairy cows with subclinical mastitis were randomly divided into four groups.The control group received a standard diet,while the three treatment groups were supplemented with CHME at 20 g/d,40 g/d,and 80 g/d,respectively.Milk yield,milk composition （including lactose percentage,protein percentage,and somatic cell count）, and the levels of key biomarkers were recorded. These biomarkers included myeloperoxidase（MPO）,lactate dehydrogenase（LDH）,glutathione peroxidase （GPX）,superoxide dismutase （SOD）,catalase（CAT）, malondialdehyde （MDA）,interleukin-6 （IL-6）,interleukin-1β （IL-1β）,and tumor necrosis factor-α （TNF-α）.[Result] Cows supplemented with 40 g/d and 80 g/d of CHME exhibited a significant increase in milk yield,lactose percentage,and protein percentage,along with a significant reduction in somatic cell count. Concurrently,the levels of MPO and LDH decreased.Furthermore,the activities of the antioxidant enzymes GPX,SOD,and CAT were enhanced,while MDA content decreased. The expression of the pro-inflammatory cytokines IL-6,IL-1β,and TNF-α was significantly suppressed.[Conclusion] Chinese herbal medicine extract effectively improved milk yield and quality in cows with subclinical mastitis.It regulated the levels of active enzymes in milk,enhanced antioxidant capacity,and inhibited the expression of inflammatory cytokines,demonstrating good preventive and therapeutic effects.

Key words: subclinical mastitis, dairy cows, milk yield, somatic cell count