Propolis as an alternative remedy for the treatment of subclinical mastitis in dairy cows

Background: Subclinical mastitis is a widespread condition in dairy cows, often treated with antibiotics. Due to rising antimicrobial resistance, natural alternatives like propolis are gaining interest. Objectives: To evaluate the antibacterial efficacy of 5 and 10% propolis alginate emulsions in cows with subclinical mastitis and assess their effects on milk quality and systemic biomarkers. Methods: Ten dairy cows diagnosed with subclinical mastitis were divided into two treatment groups (5 and 10% propolis emulsions). Emulsions were administered intramammarily and orally for 5 days. Bacterial load in milk, milk composition, blood biochemical and immunological parameters, phenolic compound profiles, and antioxidant activity were analysed using standard microbiological and biochemical methods. Results: < 0.05). Significant changes were observed in hepatic enzymes (ALT, AST), electrolytes (Ca, Mg, P), and renal markers (creatinine, urea). Immunological shifts included an increase in lymphocytes (+21%) and a decrease in neutrophils (-30%) in the 5% group. Antioxidant capacity was confirmed, with the highest activity observed in CUPRAC and ABTS assays. Phenolic compounds, including p-coumaric acid and flavonoids, contributed to the bioactivity. Conclusion: A 5% propolis alginate emulsion was more effective than the 10% formulation in reducing bacterial counts and improving immunological and biochemical profiles. These findings support propolis as a promising natural alternative for treating subclinical mastitis, warranting further investigation into optimal formulations and long-term safety.