BVD Type I and Type II SN Titer Response in Weaning Age Beef Calves Following the Administration, in Various Combinations, of Two MLV Vaccines Containing Different BVD Type 1 and Type 2 Strains

Abstract

Many preconditioning and feedlot vaccination protocols require two doses of BVD vaccine. Typically the same vaccine and same strains of BVD are used for each dose. Following vaccination, the immune response will be strongest against the strains of BVD virus in the vaccine; however, the immunity developed must also protect against exposure to heterologous strains in the field. Due to antigenic diversity in BVD virus, it is important to stimulate immunity against as wide array of viruses as possible. Theoretically, using combinations of different vaccines containing different strains of BVD will expose the immune system to a wider range of BVD virus. Whether this results in an improved immune response or broader protection against field strains of BVD remains to be proven. The objective of this study was to determine if vaccination with different combinations of two modified live virus vaccines, containing different strains of BVD Type 1 and 2, would improve serum neutralization (SN) titer response and weight gain.