AUTHOR=McAtee Taylor B. , Pinnell Lee J. , Powledge Sherri A. , Wolfe Cory A. , Morley Paul S. , Richeson John T. 

TITLE=Effects of respiratory virus vaccination and bovine respiratory disease on the respiratory microbiome of feedlot cattle

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1203498

DOI=10.3389/fmicb.2023.1203498

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>The objectives of this study were to evaluate the impacts of two modified-live virus (MLV) vaccination protocols and respiratory disease (BRD) occurrence on the microbial community composition of the nasopharynx in feedlot cattle.</p></sec><sec><title>Methods</title><p>The treatment groups included in this randomized controlled trial included: 1) no viral respiratory vaccination (CON), 2) intranasal, trivalent, MLV respiratory vaccine in addition to a parenteral BVDV type I and II vaccine (INT), and 3) parenteral, pentavalent, MLV respiratory vaccination against the same agents (INJ). Calves (<italic>n</italic> = 525) arrived in 5 truckload blocks and were stratified by body weight, sex, and presence of a pre-existing identification ear-tag. A total of 600 nasal swab samples were selected for DNA extraction and subsequent 16S rRNA gene sequencing to characterize the microbiome of the upper respiratory tract. Nasal swabs collected on d 28 from healthy cattle were used to evaluate the impact of vaccination on upper respiratory tract (URT) microbial communities.</p></sec><sec><title>Results</title><p>Firmicutes were less abundant in INT calves (<italic>n</italic> = 114; <italic>P</italic> &lt; 0.05) and this difference was attributed to decreased relative abundance (RA) of <italic>Mycoplasma spp</italic>. (<italic>P</italic> = 0.04). <italic>Mannheimia</italic> and <italic>Pasteurella</italic> had lower RA in INT (<italic>P</italic> &lt; 0.05). The microbiome in healthy animals on d 28 had increased Proteobacteria (largely <italic>Moraxella</italic> spp.) and decreased Firmicutes (comprised almost exclusively of <italic>Mycoplasma spp.</italic>) compared to animals that were treated for or died from BRD (<italic>P</italic> &lt; 0.05). Cattle that died had a greater RA of <italic>Mycoplasma spp</italic>. in their respiratory microbiome on d 0 (<italic>P</italic> &lt; 0.02). Richness was similar on d 0 and 28, but diversity increased for all animals on d 28 (<italic>P</italic>&gt;0.05).</p></sec>