A recent research project led by Cheryl Waldner and colleagues at the Western College of Veterinary Medicine has found that the 2018 shift to prescription-only access for medically important antimicrobials has had minimal impact on antibiotic use practices in Canada’s cow-calf sector. The study, completed in November 2024 under BCRC project ANH.10.19, offers insight into how the industry has adapted and highlights areas for continued stewardship.
Key Findings:
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Antibiotic Use Remains Low:
Most cow-calf herds still use antimicrobials to treat individual animals, primarily for calf respiratory illness, diarrhea, and adult cow lameness. However, usage remains relatively limited—typically affecting less than 5% of animals in a herd. -
Awareness and Stewardship:
The majority of producers are aware of antimicrobial resistance (AMR) issues and recognize their importance. Most reported no major changes in how or when they use antibiotics, nor in access or cost, since the regulatory change. Veterinarians continue to be the primary source of antimicrobial information for producers. -
Resistance Patterns:
AMR surveillance in 50 herds found low resistance in E. coli (16% of isolates resistant) and higher resistance in Enterococcus (85%), though much of the latter is attributed to natural resistance, not antimicrobial use. Only one notable link was found—between macrolide use and resistance in Enterococcus species. -
Veterinary Perspective:
Veterinarians reported an uptick in client demand and support time, especially during onboarding, as a result of the prescription-only rule. This has led to some shifts in prescribing practices, though overall antimicrobial use patterns remain stable.
Conclusion:
The switch to prescription-only antimicrobials has not drastically altered how antibiotics are used in cow-calf herds, but it has enhanced veterinary oversight and producer awareness. Continued collaboration on stewardship and resistance monitoring will be key to protecting both animal health and public trust.
