Vaccination and biosecurity are the only non-antibiotic approaches assessed as having strong field-scale evidence for reducing antimicrobial use in livestock, according to a new critical narrative review published open access in Discover Animals.
The review examines how prepared different interventions are for practical deployment on farms. It concludes that bacteriophage therapy, antimicrobial peptides, microbiome-based approaches and selective breeding remain at earlier stages of development, with evidence that is not yet sufficiently mature to support routine use across livestock systems.
Evidence was assessed across several livestock sectors
The analysis considered laboratory and in vitro research, controlled field trials, farm-level observational studies, and international surveillance or policy reports. The literature came mainly from poultry, swine, cattle and aquaculture, with more limited coverage of companion animals. The review therefore provides a broad livestock assessment rather than a sheep-specific evaluation.
Evidence was gathered through targeted searches of PubMed, Scopus and Google Scholar, alongside citation tracking. The authors classified each intervention as strong, moderate, emerging or mixed, based on the amount, consistency and design of the available research.
- Strong: vaccination and biosecurity, supported by field-scale evidence for reducing antimicrobial use.
- Earlier-stage: bacteriophage therapy, antimicrobial peptides, microbiome-based approaches and selective breeding.
- Assessment method: a qualitative framework developed by the review authors rather than an external grading system.
Review highlights different measures of success
A central point in the analysis is that three outcomes often treated as interchangeable should be separated: a reduction in pathogen burden, a reduction in antimicrobial use, and a reduction in antimicrobial resistance. Lower antibiotic consumption alone does not demonstrate an antimicrobial-resistance benefit unless resistance itself, or a relevant indicator of it, has also been measured.
The authors describe their synthesis as purposive rather than exhaustive or reproducible. No fixed date range or systematic screening protocol was applied, and the classification was not derived from GRADE, PRISMA or another external evidence system. The comparative findings should therefore be read as an informed synthesis of the literature, not as a quantitative meta-analytic estimate.
For sheep and other livestock sectors, the review places the greatest evidential weight on established disease-prevention measures, while identifying several newer technologies as areas where further research is still needed before their contribution to antimicrobial-resistance control can be judged with the same confidence.
