Patterns and factors influencing antibiotic use among poultry farmers in Thai Nguyen province, Vietnam

Understanding the patterns and drivers of antibiotic use in poultry production is essential for designing effective stewardship and farm management strategies. We analysed antibiotic use patterns, farm management practices, and factors influencing use among 398 semi-intensive poultry farms in Thai Nguyen province, Vietnam. Data on antibiotic use and mortality during the last production cycle, and biosecurity measures were collected using a structured questionnaire and analyzed descriptively and statistically. Antibiotic use was reported by 77 % of intensive farms, 70 % medium-scale farms and 33 % small-scale farms, with 76 %, 59 % and 54 % of these respectively, indicating use for therapeutic purposes. Doxycycline and Amoxicillin were the most used antibiotics on intensive and medium-scale farms, while tylosin and amoxicillin were common on small-scale farms. Biosecurity levels were low across all farm types, although intensive farms reported higher implementation. Farmers prioritised external biosecurity measures, particularly those related to infrastructure, biological vectors, and feed and water management. Mortality rates were low, averaging 1.5 % on intensive farms, 3 % on medium-scale farms, and 1.7 % on small-scale farms. In small-scale farms, antibiotic use was significantly associated with the presence of other poultry types (OR: 3.3), farmers' perception of antibiotic effectiveness (OR: 2.3), having a fence (OR=3.3) and high morbidity (OR=1.1). Storing feed on elevated floors reduced likelihood of use (OR=0.2). On medium-scale farms, high morbidity (OR=1.3) and storing feed in a separate room (OR=3.5) were linked to increased use. Among intensive farms, high morbidity was associated antibiotic use (OR=10.7). These findings highlight the need for targeted interventions to strengthen biosecurity, enforce regulations, and promote responsible antibiotic use in Vietnam's poultry sector.