Animal Industry Report

Extension Number

ASL R3134



Summary and Implications

Initial antibody titers are maternally-derived from colostrum, then decay with age. Change in antibody titer levels were compared between four viruses contributing to the Bovine Respiratory Disease Complex (BRDC), and evaluation of response to vaccination indicated that antibody production will not occur when high levels of maternal antibodies are present. The maternal antibodies were found to decay with calf age for each of the four viruses, which allowed for the estimation of a maximum circulating titer level under which a positive antibody response to vaccination could occur. Phenotypic correlations were calculated between the antibody titers for the four viruses across multiple time points. Results indicate a difference in the response to vaccination between the four virus antigens