Effect of fence-line or drylot weaning on the health and performance of beef calves during weaning, receiving, and finishing11Contribution no. 16-059-J from the Kansas Agricultural Experiment Station

Angus × Hereford beef heifers and steers (n = 460; initial BW = 225 ± 35kg) were randomly allocated to 1 of 3 ranch-of-origin weaning methods 28 d in duration: drylot weaning + dam separation (D), pasture weaning + fence-line contact with dams (PF), and pasture weaning + fence-line contact with dams + supplemental feed delivered in a bunk (PF+S). Calves assigned to D were fed a diet formulated to promote an ADG of 1kg at a DMI of 2.5% of BW (17.7% CP and 0.93 Mcal of NEg/kg). The PF calves had access to native forage, and PF+S calves had access to native forage and received the diet fed to D at a rate of 1% of BW 3× weekly. After the 28-d weaning period, calves were transported 4h to a feedlot, penned according to treatment (n = 6 pens per treatment), and fed a receiving diet (14.9% CP and 0.93 Mcal of NEg/kg) ad libitum for 60 d before transition to a finishing diet. During the first 6 d of receiving, the proportion of calves in each pen that approached the bunk and ate immediately following feed delivery at 0700h was recorded by 2 trained observers. Weaning-phase ADG was greater (P < 0.01) for D than for PF or PF+S; however, morbidity during weaning tended to be greater (P = 0.08) in D than in PF or PF+S. Receiving ADG of D was greater (P = 0.01) than of PF and PF+S. Fewer PF calves were observed at the bunk during the first 5 d of receiving (treatment × day; P < 0.01) than D or PF+S calves; however, the proportion of calves observed at the bunk was not different (treatment × day; P = 0.64) among treatments on d 6. Consequently, receiving DMI and G:F were greater (P ≤ 0.01) for D than for PF calves. Steers assigned to D were heavier (P < 0.01) than steers assigned to PF or PF+S at the beginning of the finishing period; however, steers assigned to PF had greater finishing ADG (P < 0.01) than those assigned to D or PF+S. There were no treatment differences (P ≤ 0.14) in days on feed or finishing period DMI; therefore, finishing G:F was greater (P < 0.01) for PF than D or PF+S. Carcass characteristics were not different (P ≥ 0.36) among treatments. Under the conditions of the current experiment, acclimating pasture-weaned calves to feed bunks during preconditioning had no effects on feedlot health and performance.