Development and Evaluation of a Farm-Level Antimicrobial Stewardship Intervention in Smallholder Cattle Farms

Thesis Abstract

Antimicrobial resistance poses a mounting threat to animal and public health, driven in part by the unregulated use of antimicrobials on smallholder cattle farms. This study addresses the gap between policy and practice by developing and evaluating a farm-level antimicrobial stewardship (AMS) intervention tailored to smallholder systems where access to veterinary services is limited and knowledge gaps about prudent antimicrobial use are common. The primary aim is to design, implement, and assess an AMS program that reduces inappropriate antimicrobial use while maintaining cattle health and productivity. Specific objectives are to (i) characterize current antimicrobial use patterns and drivers on 120 smallholder cattle farms in a defined peri-urban region; (ii) develop a theory-informed AMS intervention comprising farmer education, decision-support tools, record-keeping improvements, and veterinary engagement mechanisms; (iii) implement the intervention on a purposive sample of 60 farms with matched controls over a 12-month period; (iv) evaluate changes in antimicrobial use indicators, animal health outcomes, and economically relevant metrics; and (v) assess acceptability, feasibility, and scalability of the intervention using qualitative and quantitative data. The study adopts a mixed-methods design underpinned by the Behavior Change Wheel and the Theory of Planned Behavior to inform intervention content and anticipate behavior change dynamics. The population comprises cattle-keeping households in two districts with high smallholder density. A two-stage sampling approach yields 60 intervention and 60 control farms, with smallholder units as the analytical focus. Data collection instruments include structured farm surveys, on-farm antimicrobial purchase and usage records, animal health logs, and semi-structured interviews with farmers and local veterinarians. Validity and reliability are addressed through pilot testing of survey instruments (n=15) and intercoder reliability checks for qualitative transcripts (Cohen’s kappa >0.70). Quantitative analysis employs difference-in-differences regression to estimate effects on defined antimicrobial use indicators (defined daily doses, duration of treatment, and proportion of therapeutic vs. prophylactic use) and on morbidity, mortality, milk yield, and feed efficiency. Survival analysis will examine time-to-event outcomes for disease incidence, while cost-effectiveness analysis compares intervention and control farms. Qualitative data are analyzed using thematic analysis to extract themes related to perceived usefulness, barriers, and enablers of AMS adoption, with triangulation across data sources to enhance credibility. Key expected findings include a statistically significant reduction in total antimicrobial use (DID estimate >-20%), a shift toward therapeutically justified usage, improved record-keeping compliance, and maintained or improved productivity metrics (milk yield and calving intervals) without increasing veterinary costs substantially. The study anticipates reductions in disease incidence for key bovine conditions when aligned with improved husbandry practices promoted by the intervention. Regression results are expected to reveal that access to timely veterinary advice, enhanced farmer knowledge, and simplified decision-support tools are significant predictors of reduced inappropriate antimicrobial use. The research contributes to knowledge by providing robust, context-specific evidence on the design and evaluation of farm-level AMS programs for smallholder cattle systems, integrating behavioral theory with practical interventions, and generating a scalable model for policy-makers and extension services. It advances methodological rigor in measuring antimicrobial use in smallholder settings and demonstrates a feasible, cost-effective approach to improving antimicrobial stewardship without compromising animal health or farm livelihoods. The study concludes that a participatory, veterinarian-facilitated AMS intervention, anchored by improved record-keeping and decision-support tools, can effectively reduce inappropriate antimicrobial use on smallholder farms. Recommendations include scaling the intervention through district veterinary offices, integrating AMS training into existing extension programs, establishing mandatory record-keeping, and fostering public-private partnerships to sustain farmer engagement and monitoring.