Intranasal booster vaccination of beef steers reduces clinical signs following experimental coinfection with BRSV and BHV-1 without reducing shedding of BRD-associated bacteria.

Autor:	Martínez DA; Department of Clinical Sciences, College of Veterinary Medicine, Louisiana State University, Baton Rouge, LA., Chamorro MF; Department of Clinical Sciences, College of Veterinary Medicine, Louisiana State University, Baton Rouge, LA., Passler T; Department of Clinical Sciences, College of Veterinary Medicine, Louisiana State University, Baton Rouge, LA., Huber L; Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL., Falkenberg S; Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL., Walz PH; Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL., Thoresen M; Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS., Raithel G; Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL., Silvis S; Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL., Dimitrov KM; Texas A&M Veterinary Medical Diagnostic Laboratory, College Station, TX., Stockler R; Department of Clinical Sciences, College of Veterinary Medicine, Louisiana State University, Baton Rouge, LA., Woolums AR; Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS.
Jazyk:	angličtina
Zdroj:	American journal of veterinary research [Am J Vet Res] 2024 Mar 04; Vol. 85 (5). Date of Electronic Publication: 2024 Mar 04 (Print Publication: 2024).
DOI:	10.2460/ajvr.23.11.0266
Abstrakt:	Objective: To determine the efficacy of primary or booster intranasal vaccination of beef steers on clinical protection and pathogen detection following simultaneous challenge with bovine respiratory syncytial virus and bovine herpes virus 1. Methods: 30 beef steers were randomly allocated to 3 different treatment groups starting at 2 months of age. Group A (n = 10) was administered a single dose of a parenteral modified-live vaccine and was moved to a separate pasture. Groups B (n = 10) and C (10) remained unvaccinated. At 6 months of age, all steers were weaned and transported. Subsequently, groups A and B received a single dose of an intranasal modified-live vaccine vaccine while group C remained unvaccinated. Group C was housed separately until challenge. Two days following vaccination, all steers were challenged with bovine respiratory syncytial virus and bovine herpes virus 1 and housed in a single pen. Clinical and antibody response outcomes and the presence of nasal pathogens were evaluated. Results: The odds of clinical disease were lower in group A compared with group C on day 7 postchallenge; however, antibody responses and pathogen detection were not significantly different between groups before and following viral challenge. All calves remained negative for Histophilus somni and Mycoplasma bovis; however, significantly greater loads of Mannheimia haemolytica and Pasteurella multocida were detected on day 7 postchallenge compared with day -2 prechallenge. Clinical Relevance: Intranasal booster vaccination of beef steers at 6 months of age reduced clinical disease early after viral challenge. Weaning, transport, and viral infection promoted increased detection rates of M haemolytica and P multocida regardless of vaccination status.
Databáze:	MEDLINE
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