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Characterizing the microbiota of recycled bedding sand on a Wisconsin dairy farm.

A. Steinberger




Characterizing the microbiota of recycled bedding sand on a Wisconsin dairy farm.
H. Pilch1, A. Steinberger*2, G. Suen2, N. Aulik3, D. Sockett3, C. Czuprynski1. 1Department of Pathobiological Sciences, University of Wisconsin-Madison Madison, WI, 2Department of Bacteriology, University of Wisconsin-Madison Madison, WI, 3Wisconsin Veterinary Diagnostic Laboratory Madison, WI.

Recycling bedding sand is a common practice on dairy farm operations. Little is known about the diverse microbial community in bedding sand and how it might impact dairy cattle health. Here, the microbiota of recycled bedding sand on a WI dairy farm was evaluated at various stages of the recycling process across 2 seasons. Samples of sand and gray water were collected from several locations on a Wisconsin dairy farm using sterile wooden spoons and conical tubes, once during the summer and winter of 2018. DNA was extracted from each sample and the V4 variable region of 16S rRNA genes were PCR amplified. Amplicons were sequenced on an Illumina MiSeq, processed using the mothur software package, and analyzed with R. A total of 5,064 unique operational taxonomic units (OTUs) representing 32 phyla, 289 families, and 562 genera were identified in summer samples. A core microbiota of 171 OTUs were present across all summer sampling locations suggesting persistence of bacteria across the recycling process. Bacterial community composition (BCC) of the summer samples also differed by location across the sand recycling process (P < 0.05). In winter, a total of 3,158 unique OTUs representing 28 phyla, 294 families, and 663 genera were identified. A core group of 236 OTUs were shared across all winter locations. There was no relation between location and BCC for winter samples (P > 0.05). Flavobacterium, Psychrobacter, and Pseudomonas, genera that contain known environmental mastitis pathogens, were identified as the most abundant genera in recycled bedding sand in both winter and summer. Enterococcus, another mastitis pathogen, was also found in high relative abundance but only across winter samples. These data demonstrate that recycled sand bedding contain complex bacterial communities which persist, in part, across the sand recycling process during both summer and winter. Comparison of summer and winter samples further suggest a seasonal effect on the microbiota of recycled bedding sand and gray water. Together these findings suggest that recycled bedding sand could serve as a source of infection for dairy cattle, warranting further study.

Keywords: microbiome, recycled bedding sand, dairy farm.

Biography: I am a 4th year PhD student in the Microbiology Doctoral Training Program at UW-Madison. I grew up in the dairy industry, working on my uncle's dairy farm and showing cattle at our county fair. My undergraduate work at UW-Madison focused on bacterial cellulose degradation and ruminant microbial ecology. As a graduate student I'm working to understand dairy farm antibiotic use as it relates to antibiotic resistance emergence and dissemination. I am fortunate to also work on other dairy research through several collaborations. I am passionate about the dairy industry and hope to work to improve it throughout my career.