Bovine respiratory disease decreases profitability associated with cattle feeding. The
cost of respiratory disease includes death loss, expenses associated with treatment,
and reduced growth performance. Respiratory disease also decreases carcass weights,
USDA quality grade, and ribeye area of feedlot cattle. Decreased carcass weights, fat
thickness, and ribeye area have been associated with treatment of apparent respiratory
disease when compared to animals not treated, whereas reduced incidence of the
disease resulted in improved carcass merit. Preshipment weaning and vaccination has
been found not only to prepare calves for improved performance in feedlots, but also to
reduce incidence and severity of respiratory disease.
Previous KSU research reported that length of the preshipment weaning period influenced
carcass characteristics and time on feed during finishing. Therefore, we hypothesized
that vaccination strategy and the length of the preshipment weaning period would
interact to influence calf performance during finishing as well as subsequent carcass
characteristics. The objective of our experiment was to compare the effects of respiratory
disease vaccination administered prior to weaning on the ranch of origin or after
feedlot arrival for calves weaned 45, 15, or 0 days before feedlot arrival.
