Geography, niches, and transportation influence bovine respiratory microbiome and healthOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This work re-analyzed three previously published shotgun metagenomic datasets (NCBI SRA accessions PRJNA687519, PRJNA724913, and PRJNA395911) to test how geographic location, respiratory sampling niche, and transportation stress shape the cattle (bovine) respiratory microbiome and its predicted function. The authors examined microbial diversity, composition, co-occurrence networks, and KEGG functional profiles, and assessed which opportunistic pathogens shifted after transportation in relation to bovine respiratory disease (BRD).
Who was studied?
A total of 145 respiratory samples were analyzed from feedlot calves aged 5 to 6 months across three geographic locations: Saskatoon (Canada), the cities of Qiqihaer and Guangan (China), and Alberta (Canada). Samples spanned two niches, comprising 130 nasopharyngeal swabs and 15 bronchoalveolar lavage (lung) samples, the latter collected at necropsy from calves that died of BRD. Sequencing used the Illumina HiSeq platform (shotgun metagenomics), yielding an average of 3,374,490 clean reads per sample, with taxonomy assigned via RefSeq and function via the KEGG Orthology database.
What were the most important findings?
Nasopharyngeal alpha diversity (Shannon index) was higher in the China samples (Qiqihaer and Guangan) than in the Saskatoon nasopharynx or the Alberta lung, and composition clustered distinctly by location (for example, ANOSIM R = 0.99, p = 0.001 between Saskatoon and China). Of high-quality reads, 96.72 percent were bacterial across 27 phyla; the Saskatoon nasopharynx was dominated by Proteobacteria (91.19 percent), whereas the China nasopharynx was more balanced (Proteobacteria 48.49 and 61.94 percent, Firmicutes 24.26 and 17.68 percent, Actinobacteria 14.90 and 9.40 percent, Bacteroidetes 6.59 and 6.98 percent) and the Alberta lung was dominated by Proteobacteria (58.27 percent), Firmicutes (17.03 percent), Tenericutes (14.27 percent), and Bacteroidetes (8.41 percent). Long-distance transportation significantly reduced nasopharyngeal richness at unloading and after adaptive feeding and increased BRD-associated pathogens after feedlot arrival, whereas short-distance transportation did not; the 15 BRD lung samples separated into four clusters dominated by different pathogens.
What are the greatest implications of this study?
The authors conclude that geography, sampling niche, and transportation (especially long-distance shipping) are important factors shaping the bovine respiratory microbiome and BRD, and that distinct pathogen-dominated lung clusters may reflect different subtypes of BRD pathogenesis. Because this is an observational re-analysis of existing metagenomic datasets, the results describe associations rather than causation, and the authors note the small number of lung samples as a limitation.