Effects of number of viral respiratory disease vaccinations during preconditioning on health, performance, and carcass merit of ranch-direct beef calves during receiving and finishing

Abstract

Angus × Hereford calves (n = 430; initial BW = 230 ± 32 kg) were stratified by sex, age, and BW and assigned randomly to receive 0, 1, 2, or 3 doses of modified-live respiratory disease (BRD) vaccine before feedlot placement (0X, 1X, 2X, or 3X, respectively). Calves from 2 sources were weaned 29 d before feedlot placement and placed in a weaning facility at each ranch of origin. Initial BRD vaccination occurred at weaning, and calves were revaccinated according to treatment assignments at 14-d intervals. There were no differences (P = 0.49) in the incidence of morbidity during the 29-d weaning period among treatments (11.6, 5.2, 7.4, and 5.3% incidence for 0X, 1X, 2X, and 3X, respectively). Calf ADG, DMI, and G:F during weaning were not different (P ≥ 0.56) among treatments. Calf BW and ADG were similar (P ≥ 0.54) among treatments at 27 d after receiving and 55 d after receiving. Degree of BRD vaccination had no effect (P ≥ 0.59) on DMI or G:F during receiving. Incidence of morbidity was not different (P = 0.66) among treatments during receiving. Finishing ADG, DMI, G:F, days on feed, and final BW were not different (P ≥ 0.62) among treatments. Likewise, marbling score, USDA YG, LM area, and KPH were not different (P ≥ 0.07) among treatments. Vaccination regimens did not affect (P ≥ 0.70) incidence of liver abscesses or lung lesions. Vaccination for BRD before feedlot placement did not affect receiving performance, finishing performance, or carcass characteristics of calves preconditioned on the ranch of origin.