Quantification of antimicrobial use in semi-intensive broiler farms in Kenya

The rapid global expansion of poultry production has intensified antimicrobial use (AMU) and emergence of antimicrobial resistance (AMR). Understanding patterns, timing, and quantities of AMU is essential for designing effective stewardship strategies. This study quantified AMU in semi-intensive broiler farms in Kenya using three complementary categories of metrics. Data were collected longitudinally from 73 farms across 310 production cycles over 10 months. Farmers recorded daily flock size and antibiotic administration using a standardized farm recording forms, and medicine packaging waste bins. AMU was quantified using complementary mass-based, dose-based, and count-based metrics. Overall, 16 antibiotics were administered in 68% production cycles, with 88% used in multi-antibiotic combinations. Use was predominant in early production stages, and treatment durations frequently deviated from the recommended 4-6 days; 81% of treated cycles were shorter or longer than recommended. A cumulative 292 mg/PCU was administered (mean 13 mg/PCU per cycle), with sulfadimidine, fosfomycin, and sulfamerazine accounting for the highest quantities. While 63% of antibiotics had mean UDD/DDD ratios within acceptable dosing range (0.8-1.2), treatment-course level analysis showed widespread dosing deviations, with both under- and overdosing. These findings demonstrate that a single AMU indicator can mask important exposure patterns. Integrating multiple metrics into surveillance systems is essential to guide targeted, context-specific antimicrobial stewardship in rapidly expanding poultry systems.