title: Efficacy of multivalent, modified- live virus (MLV) vaccines administered to early weaned beef calves subsequently challenged with virulent Bovine viral diarrhea virus type 2.
abstract: BACKGROUND
  Vaccination of young calves against Bovine viral diarrhea virus (BVDV) is desirable in dairy and beef operations to reduce clinical disease and prevent spread of the virus among cattle. Although protection from clinical disease by multivalent, modified-live virus (MLV) vaccines has been demonstrated, the ability of MLV vaccines to prevent viremia and viral shedding in young calves possessing passive immunity is not known. The purpose of this study was to compare the ability of three different MLV vaccines to prevent clinical disease, viremia, and virus shedding in early weaned beef calves possessing maternal immunity that were vaccinated once at 45 days prior to challenge with virulent BVDV 2.
  
  
  RESULTS
  At 45 days following vaccination, calves that received vaccines B and C had significantly higher BVDV 1 and BVDV 2 serum antibody titers compared with control calves. Serum antibody titers for BVDV 1 and BVDV 2 were not significantly different between control calves and calves that received vaccine D. Following BVDV 2 challenge, a higher proportion of control calves and calves that received vaccine D presented viremia and shed virus compared with calves that received vaccines B and C. Rectal temperatures and clinical scores were not significantly different between groups at any time period. Calves that received vaccines B and C had significantly higher mean body weights at BVDV 2 challenge and at the end of the study compared with control calves.
  
  
  CONCLUSIONS
  Moderate to low maternally-derived BVDV antibody levels protected all calves against severe clinical disease after challenge with virulent BVDV 2. Vaccines B and C induced a greater antibody response to BVDV 1 and BVDV 2, and resulted in reduced viremia and virus shedding in vaccinated calves after challenge indicating a greater efficacy in preventing virus transmission and reducing negative effects of viremia.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. mfc0003@auburn.edu.
authors.forename: Manuel F
authors.initials: MF
authors.lastname: Chamorro
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. walzpau@auburn.edu.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Walz
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. passlth@auburn.edu.
authors.forename: Thomas
authors.initials: T
authors.lastname: Passler
authors.affiliation: Department of Crop, Soils, and Environmental Sciences, College of Agriculture and Alabama Agricultural Experiment Station, Auburn University, Auburn, AL, USA. vanedza@auburn.edu.
authors.forename: Edzard
authors.initials: E
authors.lastname: van Santen
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. waldrja@auburn.edu.
authors.forename: Julie
authors.initials: J
authors.lastname: Gard
authors.affiliation: Department of Animal Sciences, College of Agriculture, Auburn University, Auburn, AL, USA. rodnisp@auburn.edu.
authors.forename: Soren P
authors.initials: SP
authors.lastname: Rodning
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. riddekp@auburn.edu.
authors.forename: Kay P
authors.initials: KP
authors.lastname: Riddell
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. galikpk@auburn.edu.
authors.forename: Patricia K
authors.initials: PK
authors.lastname: Galik
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA. zhangyi@auburn.edu.
authors.forename: Yijing
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000097:blood / Q000517:prevention & control* / Q000821:virology; D002417:Cattle; D030242:Diarrhea Virus 2, Bovine Viral / Q000472:pathogenicity*; D014765:Viral Vaccines / Q000276:immunology*; D014774:Virulence
chemical_list: D057134:Antibodies, Neutralizing; D014765:Viral Vaccines