Abstract The current study’s objective was to assess the relationship between animal growth performance, feed intake, carcass traits, feeding behavior, gas flux, and relative profitability of implanted and non-implanted finishing Angus steers. Sixty-two steers were blocked according to body weight into 2 pens and fed for 52 and 80 d, respectively. Steers within each pen were randomly assigned to a treatment: implanted with Component TE200 (IMP; Elanco Animal Health, Greenfield, IN) or not implanted (CON). Each pen was equipped with one GreenFeed automate head chamber system (AHCS) and 5 SmartFeed systems (C-Lock, Rapid City, SD) for gas flux and feed intake measurements, respectively. Data were analyzed as a randomized complete block design using JMP Pro (16. 2. 0), with significance declared at P 0. 05 and tendencies discussed between 0. 05 ≤ P 0. 10. The IMP steers had a greater (P 0. 0001) final BW and ADG compared to CON steers. Dry matter intake (DMI) was greater (P = 0. 01) for IMP steers compared to CON steers. Implanted steers had improved (P 0. 0001) feed conversion and feed efficiency when compared with CON steers and increased hot carcass weight (P 0. 0001). Ribeye area (REA) was larger (P = 0. 01) in IMP steers compared to CON steers; however, marbling score and USDA yield grade were similar (P 0. 05). There was a difference (P = 0. 04) in USDA quality grade, where CON steers had a greater proportion of more favorable quality grades (i. e. Choice+ and greater) compared to IMP steers. The IMP steers tended to have larger (P = 0. 08) session size (g of DM/visit) than CON steers. Enteric CH4 emissions of IMP steers were greater (P 0. 05) compared to CON steers. Implanted steers had greater (P 0. 05) oxygen consumption and hydrogen emission than CON steers. IMP had reduced (P 0. 05) CH4 emissions intensity (g CH4/kg ADG) compared to CON. Relative profitability was greater than 0. 00 for each treatment, with a mean difference of 140. 06/head. In summary, growth hormone implants improve productivity and efficiency of finishing steers, reducing emissions per unit of beef produced while improving profitability, especially with greater days on feed.
Swenson et al. (2026) studied this question.