Antimicrobial use in 20 U.S. beef feedyards: 2018-2019

Area of Science:

• Veterinary Medicine
• Animal Science
• Public Health

Background:

• Antimicrobial use in livestock is critical for animal health and food safety.
• Understanding usage patterns in beef feedyards is essential for responsible stewardship.
• Previous reports show variability in antimicrobial metrics, necessitating standardized reporting.

Purpose of the Study:

• To quantify antimicrobial use in a U.S. beef feedyard sample for 2018-2019.
• To detail indications for antimicrobial administration and associated treatment outcomes.
• To provide data for evaluating antimicrobial stewardship in beef production.

Main Methods:

• Convenience sample of 20 U.S. beef feedyards, covering 1,141,846 cattle.
• Antimicrobial use reported as mg active ingredient/kg liveweight sold (mg/kg-LW) and regimens/animal year (Reg/AY).
• Detailed analysis of regimens/100 head-in for specific indications (BRD, Lameness, LAC) in 10 feedyards.

Main Results:

• Liver Abscess Control (98.4 Reg/100 head-in) and Bovine Respiratory Disease (37.1 Reg/100 head-in) were primary indications in 2018.
• Individual animal therapy for BRD accounted for 12.9 Reg/100 head-in.
• Treatment success rates for BRD, Lameness, and Other indications were 76.5%, 86.5%, and 83.0% respectively in 2018.

Conclusions:

• Antimicrobial use patterns vary significantly by indication in U.S. beef feedyards.
• Treatment outcomes provide valuable data for assessing therapeutic efficacy.
• Methodological differences in calculating antimicrobial use metrics can lead to divergent conclusions.