title: Effect of age at the time of vaccination on antibody titers and feedlot performance in beef calves.
abstract: OBJECTIVE
  To compare antibody responses, feedlot morbidity and mortality rates, feedlot performance, and carcass value for calves vaccinated with 1 of 2 vaccination strategies and for unvaccinated control calves.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  451 beef steers and heifers.
  
  
  METHODS
  Calves were vaccinated with a modified-live infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea virus types 1 (BVDV1) and 2 (BVDV2), parainfluenza type 3 virus, and bovine respiratory syncytial virus vaccine and Mannheimia haemolytica and Pasteurella multocida bacterin-toxoid at approximately 67 and 190 days of age (group 1; n = 151) or at approximately 167 and 190 days of age (group 2; 150) or were not vaccinated (control; 150). Serum antibody titers were measured at approximately 2, 67, 167, 190, and 232 days of age. Morbidity and mortality rates, feedlot performance, and carcass value were recorded for 361 calves shipped to feedlots.
  
  
  RESULTS
  Percentages of calves seroconverting to IBRV, BVDV1, and BVDV2 were significantly higher for groups 1 and 2 than for the control group. Mean treatment costs were significantly lower for vaccinated than for control calves, and mean mortality rate was significantly higher for control calves than for group 1 calves. Feedlot performance and carcass value did not vary significantly among groups.
  
  
  CONCLUSIONS
  Results suggested that vaccination of beef calves with a 5-antigen modified-live virus vaccine at 67 and 190 days of age was as effective in terms of immunologic responses as was vaccination at 167 and 190 days of age.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Arts and Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Kirkpatrick
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Step
authors.forename: Mark E
authors.initials: ME
authors.lastname: Payton
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Richards
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: McTague
authors.forename: Jeremiah T
authors.initials: JT
authors.lastname: Saliki
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Confer
authors.forename: Billy J
authors.initials: BJ
authors.lastname: Cook
authors.forename: Shan H
authors.initials: SH
authors.lastname: Ingram
authors.forename: John C
authors.initials: JC
authors.lastname: Wright
mesh_terms: D000367:Age Factors; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D002417:Cattle; D002418:Cattle Diseases / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D008297:Male; D014611:Vaccination / Q000379:methods / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D014777:Virus Diseases / Q000401:mortality / Q000517:prevention & control / Q000662:veterinary*
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated; D014765:Viral Vaccines