Abstract
Antimicrobial resistance (AMR) constitutes one of the most pressing global health threats, with livestock production serving as a critical reservoir and amplifier of resistant bacteria and resistance genes. Dairy cattle production relies heavily on antimicrobial agents for the treatment, control, and prevention of infectious diseases—particularly mastitis, respiratory infections, and neonatal calf diarrhea—creating sustained selective pressure that drives the emergence and dissemination of AMR. This comprehensive review synthesizes current scientific evidence on antibiotic use practices in dairy cattle and their association with antimicrobial resistance, examining the quantitative relationship between antimicrobial consumption and resistance prevalence, the molecular mechanisms underlying resistance development, and the epidemiological patterns of resistant pathogens in dairy systems worldwide. The review documents that mastitis treatment accounts for the majority of antimicrobial use in dairy herds, with significant regional variation in consumption patterns and regulatory oversight. Critically, a positive association between antimicrobial exposure and the prevalence of resistance is consistently observed across multiple pathogens and production systems. Resistance rates exceeding 50% have been reported for penicillin and tetracycline in Staphylococcus aureus and Escherichia coli isolates from dairy cattle, with multidrug-resistant phenotypes increasingly documented globally. The transmission of resistant bacteria and resistance genes from dairy cattle to humans occurs through multiple pathways, including consumption of contaminated milk and dairy products, direct contact with animals, and environmental dissemination. Addressing this complex challenge requires integrated One Health approaches encompassing antimicrobial stewardship, enhanced surveillance systems, alternative therapeutic strategies, and improved farm management practices. This review concludes that prudent antimicrobial use, supported by robust diagnostic capabilities and farmer education, is essential for preserving antibiotic efficacy while maintaining animal health and welfare in dairy production systems