A randomized controlled clinical trial to evaluate the effect of an intranasal respiratory vaccine on calf health, ultrasonographic lung consolidation, and growth in Holstein dairy calves
Keywords:passive transfer, antibodies, BRD, bovine respiratory disease, administered vaccines, lung lesions, thoracic ultrasonography, intranasal vaccine
Although passive transfer of antibodies to the newborn calf provides many great benefits, high levels of maternal antibodies may limit the ability of the calf to respond to parenterally administered vaccines against the respiratory viruses associated with bovine respiratory disease (BRD). Experimental challenge studies have demonstrated varying levels of efficacy of vaccines administered via the intranasal route. Unfortunately, direct identification of lung lesions associated with BRD requires euthanasia and often limits the size of study populations. As an alternative, thoracic ultrasonography (US) can be performed quickly and provides an accurate antemortem assessment of lung health. Therefore, the purpose of this randomized controlled clinical trial was to evaluate the effect of an intranasal vaccine on calf health, ultrasonographic lung lesions, and growth in young Holstein calves.