The specific antimicrobial resistance (AMR) decreases that can be expected from reducing antimicrobial (AM) use in United States (US) beef production have not been defined. To address this data gap, feces were recovered from 36 lots of ?raised without antibiotics? (RWA) and 36 lots of ?conventional? (CONV) beef cattle. Samples (N = 719) were collected during harvest and distributed over a year. AMR was assessed by:i) culture of six AM-resistant bacteria (ARB); ii) qPCR for 10 AMR genes (ARGs); iii) an qPCR array of 84 ARGs; and iv) metagenomic sequencing. Generally, AMR levels were similar, but some were higher in CONV. The prevalence of third-generation cephalosporin-resistant (3GCr) Escherichia coli was marginally different between production systems (47.5 % CONV, 34.8% RWA, P = 0.04), but the seasonal effect (92.8% summer, 48.3% winter, P