Interpretive Summary: Effects of vaccination timing against respiratory pathogens on performance, antibody response, and health in feedlot cattle.
By: Anne Wallace
In this paper published in the February 2019 Journal of Animal Science, researchers evaluated how vaccine timing affected immunity to bovine respiratory diseases (BRD) in feedlot cattle. The researchers hypothesized that vaccinations given prior to the highly stressful feedlot entry period would be most beneficial to cattle performance and health.
Finding ways to mitigate or eliminate BRD in cattle is an important area of research in animal science. Dr. Cooke, corresponding author of this study, says “bovine respiratory disease… is the most common and costly disease in US feedlots. These economical losses include, besides cattle mortality, costs associated with wasted feed resources, purchase of pharmaceuticals, and reduced performance of morbid cattle.” Animals affected by BRD viruses may also become susceptible to secondary bacterial infections, which can be devastating. Although vaccination may reduce the incidence of BRD, immune responses to vaccines may be less effective on stressed animals.
A total of 159 calves were used in this study. Vaccinations were given at the following time intervals: at (1) weaning & day of feedlot arrival – control group (CON), at (2) 15 days before weaning & 15 days before feedlot arrival (EARLY), and at (3) 15 days after weaning & 15 days after feedlot arrival (DELAYED). Cattle were slaughtered on day 306. Body weight (BW), blood samples, and signs of BRD were regularly assessed throughout the study.
Cattle BW and average daily gain (ADG) was not significantly different between the three groups. The incidence of BRD was reduced in animals vaccinated prior to feedlot entry (EARLY) compared to CON and DELAYED groups. Blood tests to measure viral immune response (titers) to vaccination was greater in EARLY compared to CON and DELAYED animals for several time periods within the first 60 days after feedlot entry.
This study supports vaccination timing as an important consideration in the prevention of BRD. The authors’ hypothesis that extreme stressors may affect vaccine response also appears to be supported per reduced incidence of BRD and increased viral titers with early vaccination. Overall, BRD vaccination administered prior to the highly stressful feedlot entry period may be justified. Further studies to reconfirm findings and to determine if early vaccination to other bovine diseases is effective in reducing incidence may also be warranted.
To view the article, visit the Journal of Animal Science.