Abstract
INTRODUCTION: The present study explored the immune response, milk production and health status of mastitis-infected lactating cows fed diets supplemented with Macleaya cordata extract. METHODS: Twenty-four Holstein and Jersey cows were equally assigned to two experimental groups: the first group was fed a control diet (control), and the second experimental group was fed a control diet plus Macleaya extract at 8 g/head/d (Macleaya). The experiment was conducted for 60 days. The daily milk yield was recorded, and the milk samples were analyzed for total solids, fat, protein, and lactose contents. RESULTS: Blood samples were analyzed for different blood constituents, biochemical parameters, antioxidant capacity and immune indices. Compared with the control, the addition of Macleaya improved immune indices (p < 0.05). No significant differences (p > 0.05) were recorded between the two groups for different rumen liquor parameters, antioxidant capacities, milk yields or compositions. However, supplementing the diet with Macleaya significantly decreased SCC, SAA, and endotoxin. CONCLUSION: This study suggested that supplementing the diets of lactating cows with Macleaya extract potentially improved their immune competence without adversely impacting their productive performance.