ABSTRACT
Antibiotics are an essential tool for combatting bacterial diseases and their use has contributed to increased welfare of both human beings and animals. The discovery of penicillin in the late 1920s revolutionized medicine and the first veterinary use of this compound is reported to have been for treatment of mastitis in dairy cows (Mitchell et al., 1998). Antibiotics came into common use beginning in the late 1940s and concerns about emergence of antimicrobial resistance were noted almost immediately (Prescott, 2006). Initially, concerns about the development of resistance were minimal because new classes of drugs were continually being developed, but contemporary researchers have noted the gradual emergence of resistance to all classes of drugs and resistance mechanisms have been identified for all antibiotics (Boerlin and White, 2013). The issue of antibiotic
resistance has gained attention globally and this issue will continue to be relevant for dairy farmers and the veterinarians who advise them.
