Environmental impacts associated with the removal of productivity-enhancing technologies from three different beef steer post-weaning management systems

Environmental impacts of recently weaned Angus–continental steers raised without (NAT) or with (CON) productivity-enhancing technologies (PETs) in the form of hormonal implants (Ralgro®, Revalor®-G Revalor®-S, tylosin, monensin) were investigated. Heavy steers (295 ± 11 kg; SD) were direct finished, Medium steers (250 ± 11 kg) were confined backgrounded (98 ± 8 days) before finishing, and Light (205 ± 11 kg) steers were backgrounded (195.5 ± 7.5 days) and summer-grazed (67.5 ± 12.5 days) before finishing. Use of PETs resulted in six management strategies ( n = 40 hd treatment −1 ): Heavy conventional (HCON), Heavy natural (HNAT), Medium conventional (MCON), Medium natural (MNAT), Light conventional (LCON), and Light natural (LNAT). The NAT steers were not implanted, while the CON steers were implanted at arrival, at the start of backgrounding and finishing. Steers were finished to a target weight of 646 kg. CON steers had 10%–13% lower greenhouse gas emissions (kg CO 2 e), 10%–32% lower NH 3 emissions, 9%–22% lower land requirements (ha), and 12%–25% lower water use (m 3 ) per kg boneless beef compared to NAT steers. Further, HCON steers had a lower environmental impact compared to MCON and LCON. In conclusion, PETs lowered the environmental impact of all beef production systems.