Length of weaning period but not timingof vaccination affects feedlot receivingperformance and health of fall-weaned,ranch-direct beef calves

摘要

Weaning and preconditioning programs are thought to be crucial to calf health andperformance during the finishing period. The stress of maternal separation, changes indiet, environmental changes, and exposure to unfamiliar pathogens increase susceptibilityof recently weaned calves to bovine respiratory disease. Vaccination programs areimplemented near weaning to decrease the incidence of respiratory disease.Many vaccination strategies are practiced by cow-calf producers in the United States.The most cautious strategy involves vaccination against respiratory disease pathogens2 to 4 weeks before maternal separation followed by a booster at weaning. This strategyis used in instances in which time, labor, and facilities are available to gather and processcalves while they are still suckling. Another common strategy is to defer vaccinationuntil after calves have been shipped to a feedlot. Deferring vaccination until arrival infeedlots is thought to increase incidence of respiratory disease compared with vaccinationprograms implemented at the ranch of origin. This assumption has not been widelyscrutinized for native Kansas cattle that are finished in Kansas feedlots.