085 Impact of Three Weaning Strategies on Calf Activity and Behavior at Weaning and Productivity after Weaning.

Weaning is a stressful time in a calf's life. Stress has been linked to reduced feed intake and diminished immune response predisposing calves to illness and poor gain. Applying anti-suckling nose flaps, to separate loss of milk from loss of contact with the dam, may reduce weaning stress. The goal of this study was to compare nose flaps (N) inserted 7 d before weaning, with abrupt weaning (A), and late weaning (L, 49 d later). Calves (n = 120, BW = 270 ± 18 kg) were blocked by hair coat quality (slick or normal at birth, as a part of a separate trial) and BW 28 d before traditional weaning and randomly assigned to treatment (10/treatment/year, 4 yr). Accelerometers were placed on 5 calves' necks/treatment/year to record relative activity 7 d prior to placement of nose flaps (A and N) or weaning (L). After collar placement, behavioral observations were made over 4 d per week for 1-h intervals beginning at 0730, 1130, and 1530h. At weaning, nose flaps were removed, A and N calves placed in a dry lot, dams of A and N relocated out of sight, and L calves with their dams relocated to a separate pasture for 49 d. Weaning age for A, N, and L was 249, 245, and 300 d ( ± 11), respectively. Data were analyzed with Proc Mixed of SAS. Accelerometer output showed similar activity patterns between treatments with a tendency for greater activity when calves were grazing in the absence of hay, than when hay was offered on pasture or during confinement (P = 0.07). Vocalizations were similar across treatments prior to weaning (2.6/steer/h; P > 0.26). Vocalizations were higher on d 1 and 2 after weaning for A (33 and 26/steer/h) and L (27 and 15/steer/h) steers as compared to N (6 and 3/steer/h, treatment P < 0.01), suggesting reduced stress. Vocalizations for A and L returned to preweaning levels by d 3 after weaning. Pacing comprised 19 and 20% of observations for A and L, respectively, during the same period and 14% for N (P < 0.01), also suggesting reduced stress. While N calves appeared less stressed at weaning, 42-d post-weaning ADG were greater for A and L (0.56 and 0.67 kg/d, respectively) than N (0.41 kg/d; P < 0.01). Of the calves that retained their flaps, 17 of 33 developed nasal ulcers from the flaps. While nose flap insertion reduced calf behavioral signs of stress, it also reduced post-weaning growth performance.