The impact of commingling preconditioned calves on mortality, morbidity and performance in a feedlot

Abstract

Bovine respiratory disease (BRD) is the most important disease in the North American beef industry, causing substantial eco­nomic losses due to morbidity and mortality, including treat­ments, reduced performance, and increased antimicrobial use. Preconditioning (PC) to mitigate BRD was proposed as early as 1967 and constitutes management practices that reduce stressors and optimize resilience through vaccination against bacterial and viral pathogens, optimized timing of dehorning, castration, best weaning strategy, and training calves to eat from a bunk and drink from a water source at least 45 d before transport to the feedlot. Despite proven profits for precondi­tioning of beef calves, PC hasn’t been established in the current beef industry. Besides the lack of premiums paid, there is also the question if commingling of PC and auction-derived (AD) calves in the feedlot can hamper PC calves’ expected growth and health advantages. Therefore, our objective was to evalu­ate the impact of optimally preconditioned calves on mortality, morbidity and average daily gain (ADG) during the first 40 days in the feedlot when PC calves where commingled with different proportions of AD calves (25, 50, 75%).