Effect of supplemental trace minerals from injection on health and performance of highly stressed, newly received beef heifers

Injectable trace minerals administered on arrival to highly stressed beef calves may improve health and performance during the critical receiving period. Crossbred beef heifers (n = 90; initial BW = 199 ± 6.4 kg) were obtained from auction markets, blocked by BW, and assigned randomly to 1 of 3 treatments: 1) s.c. injection of trace mineral solution containing Zn (20 mg/mL), Mn (20 mg/mL), Cu (10 mg/mL), and Se (5 mg/mL) (TM1; 1 mL/45.5 kg); 2) s.c. injection of trace mineral solution containing Zn (48 mg/mL), Mn (10 mg/ mL), Cu (16 mg/mL), and Se (5 mg/ mL) (TM2; 1 mL/45.5 kg); or 3) negative control (CON). Calves were offered ad libitum access to a common diet and were evaluated daily for clinical signs of bovine respiratory disease. Overall ADG was greater (P < 0.01) for calves receiving either trace mineral injection compared with CON; however, ADG did not differ (P = 0.59) between the 2 mineral treatments. Total DMI was greater (P = 0.01) for TM1 and TM2 than for CON. Total G:F was also improved (P = 0.02) for the 2 trace mineral treatments. Calves receiving TM1 and TM2 gained 0.18 and 0.19 kg, respectively, per kilogram of feed consumed; CON gained 0.16 kg per kilogram of feed consumed. Calves administered TM1 had reduced (P = 0.02) bovine respiratory disease morbidity rates compared with CON, with TM2 being intermediate. Antibiotic treatment cost was greater (P = 0.03) for CON than for TM1 or TM2. Administration of a trace mineral injection during initial processing of highly stressed, newly received heifers improved ADG, feed efficiency, bovine respiratory disease morbidity, and antibiotic treatment cost.