The goal of this study was to investigate the efficacy
of several commonly used BVDV vaccines, licensed for
sale in the USA, including both modified-live (Pfizer
Animal Health and Fort Dodge Animal Health) and
inactivated (Novartis Animal Health) vaccines, for
protection against fetal infection, despite prolonged
viral challenge from PI animals under field conditions.
The challenge-exposure method implemented in this
study was effective and rigorous, as determined by
evaluation of the following end points. All control
heifers were seronegative for antibodies to BVDV type
1a prior to BVDV challenge exposure. After challenge
exposure, all control heifers subsequently became
viremic, developed BVDV-neutralizing antibodies,