The nasopharyngeal microbiota of preweaned dairy calves with and without ultrasonographic lung lesions

The primary objective of this cross-sectional study was to identify associations between the diversity and composition nasopharyngeal (NP) microbiota pneumonia status, as diagnosed by ultrasonography (US), in preweaned dairy calves. Characteristics NP were compared calves with without pneumonia, US. Secondary objectives compare age, clinical respiratory score (CRS), previous antibiotic therapy. Holstein heifer (n = 50) from a southern Wisconsin enrolled at either 3 or 6 wk age; 4 sampled both time points. Antibiotic treatment history also collected for 30 d before enrollment. For purpose study, defined having lobar US, least 1 lung lobe. Following examination CRS deep swab obtained 16S rRNA amplicon sequencing. Alpha reduced that positive, beta tended be different previously treated antibiotics positive. Microbial not pneumonia. most dominant genus identified Mycoplasma spp.; however, there no association relative abundance (RA) status. median RA spp. increased 25 (95% confidence interval, CI: 3, 40) age age. Pasteurella 1.5 0.1, 3) Additionally, 2.3 0, 9) CRS-positive CRS-negative Psychrobacter 2 12) Chryseobacterium 0.15 2) antibiotics.