Effects of Respiratory Disease Risk and a Bolus Injection of Trace Minerals at Receiving on Growing and Finishing Performance by Beef Steers

Abstract Crossbred beef steers (n = 189; initial BW = 266 ± 27 kg) at low (LO) or high (HI) risk for respiratory disease were assigned randomly to receive a 5-mL s.c. trace mineral (TM) injection containing 75 mg of Cu, 25 mg of Se, 50 mg of Mn, and 200 mg of Zn, or a 5-mL s.c. injection of physiological saline (SA) upon arrival at a feedlot. Steers designated as LO were vaccinated against common diseases, treated for parasites, and weaned (45 d) before the study commenced. Steers designated as HI were vaccinated, treated for parasites, and weaned upon arrival at the feedlot. All steers were fed the same receiving diet ad libitum for a period of 28 d and monitored twice daily for symptoms of respiratory disease. Respiratory disease risk level did not affect receiving ADG (P = 0.78); however, HI steers had greater (P 0.20) for TM- or SAtreated cattle; however, a single treatment with TM at receiving was associated with increased (P = 0.04) finishing gain:feed. Finishing ADG and DMI by LO steers were greater (P 0.23) between HI and LO steers. Liver abscess incidence among LO steers was less (P