Spontaneous Bovine Mastitis Pathogens: Prevalence, Antimicrobial Susceptibility, and Sensitivity to Caesalpinia sappan Both In Vitro and In Vivo Studies

Mastitis is a major infectious disease that causes significant economic losses in the dairy industry. Current control programs primarily rely on antibiotics, contributing to the growing concerns of antibiotic resistance and drug residues in milk. This study aimed to identify the bacterial pathogens responsible for bovine mastitis, assess their antibiotic resistance profiles, and evaluate the antimicrobial effects of Caesalpinia sappan in treating mastitis through both in vitro and in vivo studies. A total of 138 bacterial isolates representing 40 species were identified from 100 milk samples collected from dairy cows raised under the Maejo Cooperative Group, Chiang Mai, Thailand, between May 2021 and February 2022. The most prevalent species was Escherichia coli (10.87%), followed by Bacillus cereus (9.42%) and Staphylococcus sciuri (7.97%). The highest resistance rates were observed for penicillin (63.04%), followed by streptomycin (60.87%) and lincomycin (57.25%). Nine isolates resisted all 18 antibiotics tested. The minimum inhibitory concentration (MIC) of Caesalpinia sappan against the identified pathogens ranged from 0.63 to 17.68 mg/ml, with the highest MIC observed against Pseudomonas luteola. In the animal experiment, treatment with a prototype of intramammary infusion derived from Caesalpinia sappan with and adding Aloe vera significantly reduced the total bacterial count and California Mastitis Test (CMT) scores (p < 0.01). These results suggest that Caesalpinia sappan exhibit antimicrobial efficacy against various mastitis bacteria and could serve as a potential alternative treatment for managing bovine mastitis in dairy cattle within the study region.