Antimicrobial use by free-stall dairy producers and veterinarians in Ontario

The primary objective of this study was to describe antimicrobial use by dairy veterinarians and producers in Ontario. Data were collected through producer and veterinary questionnaires, which were mailed and self-administered. Antimicrobial use findings were presented by categories of importance to human medicine. Both producer and veterinary respondents ranked mastitis, reproductive infections and lameness as the most common reasons for antimicrobial use in lactating cows. Responding practitioners indicated the requirement for veterinary consultation prior to dispensing antimicrobials increased as the veterinary-client-patient-relationship became more tenuous. Beta-lactam antimicrobials and tetracyclines accounted for the majority of dispensing on a frequency basis. Ceftiofur was the most frequently dispensed antimicrobial categorized as very highly important to human medicine. Potential antimicrobial resistance emergence was not a primary consideration in antimicrobial selection. Veterinarians agreed that antimicrobial use in the dairy industry was a contributor to antimicrobial resistance in cattle and not to resistance in human medicine.