Supplementary file 1_Understanding antibiotic decision-making for bovine respiratory disease: a survey of UK farm veterinarians.docx

Introduction<p>Bovine Respiratory Disease (BRD) is a major cause of morbidity and mortality in young calves and a major driver of antibiotic use in the United Kingdom (UK), making veterinary decision-making central to antimicrobial stewardship (AMS).</p>Methods<p>This study used a mixed-methods survey of UK farm veterinarians (n = 95), combining quantitative and qualitative questions, to explore diagnostic tools, antibiotic choices, and factors influencing the use of ancillary therapies.</p>Results<p>For BRD diagnosis in calves, clinical examination (36.8%), necropsy (33.7%), and rectal temperature (31.6%) were the tools most regarded as extremely important.

Oxytetracycline was the most commonly used primary antibiotic (52.6%), tulathromycin was the secondary option (38.9%), and NSAIDs were represented as the most common ancillary therapy (80.0%). The risk of antimicrobial resistance (AMR; 22.1%) and clinical experience (21.1%) primarily drove antibiotic selection. Prevention focused on colostrum management (80.0%), ventilation (65.3%), intranasal vaccines (46.3%), and injectable vaccines (40.0%).