Production, Management, and the Environment

摘要

Recycling bedding sand is a common practice on dairy farm operations.Little is known about the diverse microbial community in bedding sandand how it might impact dairy cattle health. Here, the microbiota of recycledbedding sand on a WI dairy farm was evaluated at various stages ofthe recycling process across 2 seasons. Samples of sand and gray waterwere collected from several locations on a Wisconsin dairy farm usingsterile wooden spoons and conical tubes, once during the summer andwinter of 2018. DNA was extracted from each sample and the V4 variableregion of 16S rRNA genes were PCR amplified. Amplicons weresequenced on an Illumina MiSeq, processed using the mothur softwarepackage, and analyzed with R. A total of 5,064 unique operational taxonomicunits (OTUs) representing 32 phyla, 289 families, and 562 generawere identified in summer samples. A core microbiota of 171 OTUs werepresent across all summer sampling locations suggesting persistence ofbacteria across the recycling process. Bacterial community composition(BCC) of the summer samples also differed by location across the sandrecycling process (P < 0.05). In winter, a total of 3,158 unique OTUsrepresenting 28 phyla, 294 families, and 663 genera were identified. Acore group of 236 OTUs were shared across all winter locations. Therewas no relation between location and BCC for winter samples (P > 0.05).Flavobacterium, Psychrobacter, and Pseudomonas, genera that containknown environmental mastitis pathogens, were identified as the mostabundant genera in recycled bedding sand in both winter and summer.Enterococcus, another mastitis pathogen, was also found in high relativeabundance but only across winter samples. These data demonstrate thatrecycled sand bedding contain complex bacterial communities whichpersist, in part, across the sand recycling process during both summerand winter. Comparison of summer and winter samples further suggesta seasonal effect on the microbiota of recycled bedding sand and graywater. Together these findings suggest that recycled bedding sand couldserve as a source of infection for dairy cattle, warranting further study.