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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #385180
Title: Interventions targeting the beef feedlot environment to control antimicrobial resistance: A mathematical modelling study

Author
item BEAUVAIS, WENDY - Purdue University
item Agga, Getahun
item Arthur, Terrance
item Schmidt, John
item JENNINGS, RACHEL - Applied Research Associates, Inc
item IVANEK, RENATA - Cornell University

Submitted to: Zoonoses and Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2026
Publication Date: 4/10/2026
Citation: Beauvais, W., Agga, G.E., Arthur, T.M., Schmidt, J.W., Jennings, R., Ivanek, R. 2026. Interventions targeting the beef feedlot environment to control antimicrobial resistance: A mathematical modelling study. Zoonoses and Public Health. 1-12. https://doi.org/10.1111/zph.70054.
DOI: https://doi.org/10.1111/zph.70054

Interpretive Summary: This mathematical modeling study supports observational data showing that antimicrobial resistant bacteria that colonize the ruminant gut can not only persist but also grow in warm feedlot pen environments, even when antimicrobials are not being used. Basic hygiene measures such as scraping manure from pens can contribute to the reduction of environmental antimicrobial resistant bacteria and genes. However, the model suggests that eradication of antimicrobial resistance genes from feedlot environments may be challenging to achieve even in the absence of antimicrobial use, particularly in warm temperatures. This is consistent with published observational studies.

Technical Abstract: Introduction: To address concerns about livestock as a source of antimicrobial-resistant bacteria and genes, there have been many recent efforts worldwide to study prescribing practices, optimal antibiotic use, and alternatives to antibiotic use. However, there is empirical evidence supporting the persistence of antimicrobial resistance genes at high densities in cattle pens for at least 2 years after cattle were removed. Methods: We describe a mathematical modelling framework to predict and explore the dynamics of antimicrobial-resistant enteric bacteria in food-producing animals and their immediate environments. Using the difference equation based compartmental modelling framework, we algebraically derive a formula for the relative rate of growth of antimicrobial-resistant enteric bacteria in the environment (RAMR). Results: We demonstrate that RAMR > 1 (i.e., growth) of tetracycline-resistant Escherichia coli in feedlot environments can occur under a range of plausible conditions, even in the absence of antimicrobial use in the feedlot cattle. Our model can reproduce data observed under field conditions showing rapid growth of tetracycline-resistant E. coli in the environment despite no antimicrobials being used. Finally, we demonstrate that generic hygiene measures such as scraping pen floors are likely to reduce the density of tetracycline-resistant E. coli in the farm environment considerably, especially in cold climates. Conclusions: Farm environments such as beef cattle feedlots may be conducive to persistence or even growth of antimicrobial resistant bacteria under a wide range of plausible conditions, even in the absence of antimicrobial use. The system may be quite resilient, and even stringent cleaning will likely not be sufficient to eliminate resistant bacteria from the environment in some climates, especially where freeze–thaw cycles are uncommon.