Capturing the fungal diversity in manure, lagoons, troughs, and flies at a commercial dairy

The microbiomes within dairy facilities that could serve as reservoirs for beneficial and pathogenic fungi have not been extensively explored. Though fungi can cause food safety and animal health issues, they also represent species contributing to bovine digestion and environmental nutrient cycling. This study investigated whether fungal communities from specific elements at a working dairy differed between cross-vent or flow-through, free stall barn management systems and defined the possible pathogen locations. Shotgun metagenomics was carried out on manure, lagoons, troughs, and fly samples from the barns. The diversity of species was not significantly affected by management systems, except between lagoon communities. Flies carried the highest number of unique fungal species and the most abundant potential mammalian pathogens, but there was a lack of overlapping pathogen profiles between flies and the other dairy components. Thus, it remains unclear whether the species are being efficiently exchanged between these different components of the dairy environment, mechanically or biologically. Manure harbored the most opportunistic pathogenic species, lagoons harbored the most plant pathogens and beneficial species, and troughs had the most innocuous or understudied species. The results allow dairy managers to consider advantageous management systems and focus on fungal mitigation efforts at appropriate locations within the dairy.