A comparison of temporal variation in bacterial diversity in the respiratory tracts of dairy calves receiving milk replacer alone or containing probiotics

Authors: Chitko-Mckown, Carol; TAN, JIA - Oak Ridge Institute For Science And Education (ORISE); EICHER, SUSAN - Retired ARS Employee; KRITCHEVSKY, JANICE - Purdue University; BRYAN, KEITH - Novonesis; Dickey, Aaron; McDaneld, Tara

Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/11/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: OBJECTIVE: To characterize the bacterial populations along multiple sites of the bovine respiratory tract over time in dairy calves fed control milk replacer or milk replacer containing probiotics. METHODS: Dairy calves were fed either control milk replacer (N=10) or milk replacer with probiotics (N=10) from birth to weaning, and swabs were obtained from the nares and tonsils over 9 sampling times. Lung lavage fluids were obtained from five animals in each group on day 52. DNA was extracted, and 16S ribosomal gene hypervariable regions 1-3 were sequenced. RESULTS: Temporal variation in alpha bacterial diversity was observed within the nostril, tonsil, and lung lavage samples, which indicated distinct bacterial compositions among sampling time points. The three respiratory tract regions studied showed spatial variability in bacterial taxa composition, however, oral probiotic treatment did not change alpha diversity in any respiratory tissue. Differentially abundant taxa were unique to anatomical location in treated calves, however a few were common to two locations and Finegoldia was differentially abundant in all three locations. CONCLUSIONS: The results show the potential effects of probiotics on the bovine respiratory tract microbiome and contribute to the understanding of the dynamic nature of bacterial diversity in one system.