Serum neutralizing (SN) antibody titers to cytopathic (cp) type 1a, type 1b and type 2 bovine viral diarrhea viruses (BVDV) were determined for yearling, crossbred beef heifers immunized with a modified live cytopathic type 1a BVDV vaccine, or experimentally infected with a noncytopathic (ncp) type 1b or a ncp type 2 BVDV. The results indicate that type-specific and cross-reactive SN titers are usually found to all three test viruses in an individual animal, with the highest SN titers to the same genotype of BVDV as the challenge or vaccine virus. Exceptions to this trend were found in individual animals, however, emphasizing the importance of comparing the SN titers for several animals in a herd. Determining SN titers to the three BVDV genotypes may help veterinarians distinguish the BVDV genotype involved in a herd infection from antibody titers due to vaccination.
Jones L, Van Campen H, Xu Z, Schnackel, JA: Bov Pract 35(2):137-140, 2001