Effect of age at the time of vaccination on antibody titers and feedlot performance in beef calves.
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.
Kirkpatrick
John G
JG
Department of Veterinary Clinical Sciences, College of Arts and Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
Step
Douglas L
DL
Payton
Mark E
ME
Richards
Jeffrey B
JB
McTague
Lawrence F
LF
Saliki
Jeremiah T
JT
Confer
Anthony W
AW
Cook
Billy J
BJ
Ingram
Shan H
SH
Wright
John C
JC
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*
D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated; D014765:Viral Vaccines