Comparison of the BVDV, BHV-1, and BRSV anamnestic response to modified-live or inactivated vaccines in calves previously vaccinated with a modified-live virus vaccine.

Abstract

The objective of this study was to compare the serological responses in cattle initially vaccinated with a modified-live virus (MLV) vaccine containing infectious bovine rhinotracheitis (IBR) virus, parainfluenza-3 (PI₃) virus, bovine viral diarrhoea virus type 1 (BVDV1), bovine viral diarrhoea virus type 2 (BVDV2), and bovine respiratory syncytial (BRS) virus antigens, and subsequently re-vaccinated with either the same MLV vaccine or inactivated vaccine with oil adjuvants, containing the same viral antigens. A group of 145 nursing calves received an MLV vaccine containing IBR, PI₃, BVDV1, BVDV2, and BRSV at one to two months of age. The calves were re-vaccinated with the same MLV vaccine at weaning, three-and-a-half months later. Approximately five months later, 45 of these animals were randomly selected and assigned to one of three treatment groups. Twenty calves received inactivated vaccine with oil adjuvants (IBR, PI₃, BVDV1, BVDV2, BRSV); 20 received the same MLV vaccine that they had received as calves (IBR, PI₃, BVDV1, BVDV2, BRSV); and five controls received the MLV sterile diluent. Following final vaccination, the animals receiving the inactivated vaccine with oil adjuvants had the highest titre response (P<0.05) for IBRV, BRSV, BVDV1, and BVDV2.