A pilot antimicrobial use monitoring project in 22 U.S. beef feedyards

Abstract

Research funded by an FDA Center for Veterinary Medicine cooperative agreement, describing antimicrobial use in beef feedyards, dairies, and swine, broiler, and turkey production systems, was published in November 2020 in an open access special edition of Zoonoses and Public Health. This presenta­tion reviews the published data, related to a convenience sam­ple of 22 U.S. beef feedyards, concerning antimicrobial use de­scribed by the metrics of mg of antimicrobial/kg of live weight sold (mg/kg-LW) and as regimens/animal year (Reg/AY). These metrics are further characterized by use category (in-feed, con­trol of bovine respiratory disease, and individual animal thera­py) and by antimicrobial class. Also discussed is a comparison of metric results based on use data vs. surveys as conducted in 18 feedyards. All methods and data discussed are presented in open access journal articles, and the reader is directed to these articles for in-depth coverage so that complete context of the data is maintained. Briefly, in-feed use was dominant as pre­sented by either metric, with the macrolide and tetracycline classes represented in this category therefore representing the majority of use by either mg/kg-LW or Reg/AY. When antibiotic use metrics calculated from use records and from surveys were compared, the mean value across all feedyards was similar, but values for individual feedyards could be quite different, result­ing in unreliable ranking of use by survey-derived data.