ABSTRACT
The objective was to evaluate the effects of two-stage weaning and injectable trace mineral (ITM) on receiving cattle growth performance and behavior. Angus and Simmental × Angus steers (n = 136; body weight [BW] = 200 ± 26 kg) were utilized in a 2 × 2 factorial design. Calves were blocked by source, and assigned to one of four treatments: 1) two-stage weaning and ITM (2MM), 2) two-stage weaning and saline injection (2SAL), 3) abrupt weaning and ITM (AbtMM), or 4) abrupt weaning and saline injection (AbtSAL). On d-6, calves were weighed, plastic calf weaner devices (used to prevent calf from nursing) were inserted in two-stage weaned calves, and ITM or saline injections (1 mL/45.4 kg BW) were administered. On day 0, plastic calf weaner devices were removed, and calves were weighed and shipped 272 km to Urbana, IL. Steer behavior was observed the 2 d following separation from dam. Receiving period was day 0 to 42 and growing period was day 42 to 124. Data were analyzed using the MIXED procedure of SAS and pen (six per treatment) was the experimental unit. Abruptly weaned calves had greater (P < 0.01) preweaning average daily gain (ADG) than two-stage weaned calves. Treatment did not affect (P ≥ 0.16) ADG during the receiving or growing period; however, calves that received ITM tended (P 0.06) to have greater ADG from day 0 to 124. During the receiving period, abruptly weaned calves tended (P = 0.08) to eat more than two-stage calves and ITM calves ate more (P = 0.03) than calves that received saline. There was a weaning strategy × ITM interaction (P < 0.01) for dry matter intake (DMI) from day 0 to 124; 2MM calves ate more (P < 0.01) than 2SAL, but DMI was not different (P = 0.58) between AbtMM and AbtSAL calves. There was a weaning strategy × ITM interaction (P < 0.01) for gain-to-feed ratio (G:F) from day 0 to 124; 2SAL calves had greater (P = 0.05) G:F than AbtSAL, with 2MM and AbtMM calves being intermediate and not different (P = 0.38) than each other. Two-stage weaning decreased (P ≤ 0.02) the percentage of calves walking, standing, and vocalizing, and increased (P ≤ 0.02) the percentage of calves lying and eating following separation from dam. Two-stage weaning decreased preweaning ADG and behavioral signs of stress at feedlot arrival, but had no effect on overall growth. In addition, ITM had no effect on calf BW or behavior, but increased overall DMI in two-stage weaned calves compared to abruptly weaned calves and tended to increase overall ADG regardless of weaning strategy.
