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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #398829
Research Project: Genomes to Phenomes in Beef Cattle Research

Location: Genetics and Animal Breeding

Title: Evaluation of nasal microbial communities of beef calves during pre-weaning outbreak of bovine respiratory disease

Author
item ABRAMS, AMY - Berry College
item Kuehn, Larry
item Keele, John
item GONDA, MICHAEL - South Dakota State University
item McDaneld, Tara

Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2025
Publication Date: 10/7/2025
Citation: Abrams, A.N., Kuehn, L.A., Keele, J.W., Gonda, M.G., McDaneld, T.G. 2025. Evaluation of nasal microbial communities in the upper nasal cavity of beef calves during pre-weaning outbreak of bovine respiratory disease. Animals. 15(19). Article 2914. https://doi.org/10.3390/ani15192914.
DOI: https://doi.org/10.3390/ani15192914

Interpretive Summary: Bovine respiratory disease is known to be caused by multiple viral and bacterial pathogens. Knowledge of commensal bacteria before and after animals are treated for respiratory disease can help to gain insight on whether certain bacterial strains or overall bacterial diversity can decrease susceptibility to pathogenic bacterial strains. In this study, we examined the nasal bacterial populations before, during, and after and mass medication treatment events instigated due to a respiratory disease outbreak. Bacterial profiles did change over time and were different in calves that were mass treated. This research, in combination with data from other sources, will improve the overall understanding of interactions between commensal bacterial diversity and susceptibility to disease.

Technical Abstract: Bovine respiratory disease complex (BRDC) is a leading cause of morbidity and mortality in pre-weaned calves, yet the role of commensal nasal microbiota in outbreak severity remains poorly understood. This study characterized nasal bacterial communities during two BRDC outbreaks of differing severity (moderate vs. severe) and at ~30 days post-treatment. Nasal swabs were collected from calves and analyzed using 16S rRNA gene sequencing (V1-V3 regions, Illumina MiSeq) and quantitative PCR targeting three major BRDC pathogens. Microbial community profiles differed between outbreak groups and across timepoints. Calves in the severe outbreak group exhibited lower microbial diversity compared to those in the moderate outbreak. In both groups, diversity significantly increased from outbreak to post-treatment. At the time of disease, nasal communities were dominated by the genera Mycoplasmopsis, Mesomycoplasma, and Caviibacter, with qPCR confirming Mycoplasma bovirhinis as the predominant species. These findings indicate that BRDC outbreaks in pre-weaned calves are associated with reduced microbial diversity and the dominance of pathogenic Mycoplasma species, with recovery characterized by greater bacterial diversity. Shifts in nasal microbiome composition between outbreak and post-treatment may reflect pathogen-driven disruption during disease and subsequent microbial community rebalancing.