Abstract Abstract: The objective of this experiment was to evaluate the effects of a phytogenic feed additive (PHYT) on the health and performance of newly-received, high-risk calves. Auction market derived crossbred beef steers and bulls (n = 712; initial body weight; BW = 239 ± 6.8 kg) were stratified by sex, blocked by BW, and randomly allocated to experimental treatments (n = 9 pens per treatment; n = 24 to 29 calves per pen). Experimental treatments included: a control diet (CON), 250 mg · steer⁻¹ · d⁻¹ of PHYT (PHYT250), or 500 mg · steer ⁻¹ · d⁻¹ of PHYT (PHYT500). Pen served as the experimental unit for all dependent variables. Contrasts were performed for PHYT inclusion (PHYT250 and PHYT500 vs. CON). No differences in BW existed between treatments throughout the experiment (P ≥ 0.20; PHYT vs. CON P ≥ 0.11). In the overall model, no differences (P ≥ 0.23) in average daily gain (ADG) existed between CON, PHYT250, or PHYT500. However, when comparing PHTY to the CON, ADG tended to be less in the calves receiving CON from d 0 through d 14 (P = 0.09). No differences in dry matter intake (DMI) existed between treatments throughout the experiment (P ≥ 0.27; PHYT vs. CON P ≥ 0.13). While there was no difference in gain to feed (G:F) in the overall model (P ≥ 0.26), the tendency observed for a difference in ADG from d 0 through d 14 did result in a similar tendency for G:F across the same interval when comparing PHYT to the CON (PHYT vs. CON P ≥ 0.10). A difference was observed in the percentage of steers treated once for bovine respiratory disease (BRD; P = 0.02), with CON being treated more frequently than PHYT500, while PHYT250 was intermediate and similar to both CON and PHYT500. When comparing PHYT to the CON, there was a decrease in the percentage of steers receiving PHYT to be treated once for BRD (P = 0.01). However, there were no differences in either the percentage of steers treated twice for BRD or the in the percentage of total BRD treatments administered (P ≥ 0.29; PHYT vs. CON P ≥ 0.14). The mortality percentage and the percentage of steers removed from the study were not different (P ≥ 0.16; PHYT vs. CON P ≥ 0.14); however, there tended to be more combined mortalities and removals for steers receiving PHYT than the CON (P = 0.08; PHYT vs. CON P = 0.09), with PHYT500 and CON tending to be different, and PHYT250 being intermediate and similar to both PHYT500 and CON. In summary, PHYT did not impact overall performance, but did reduce initial antimicrobial treatments for BRD.