A joint research team from the University of Minnesota and Cornell University systematically evaluated processing methods for recycled manure solids (RMS) bedding to investigate the impact of different treatment processes on pathogen levels. Published in JDS Communications, this study provides a scientific basis for bedding selection in dairy farms.

Recycled manure solids bedding is increasingly widely used in Midwestern U.S. dairy farms due to its cost-effectiveness and promotion of waste recycling. The research team conducted surveys at 27 dairy farms in Minnesota and Wisconsin, comparing four processing methods: raw solids, anaerobic digestion, secondary processing, and digestion combined with secondary processing. Cornell University postdoctoral researcher Felipe Peña-Mosca stated: "Recycled manure solids bedding supports sustainable farm operations, but whether it harbors bacteria that affect udder health still needs validation."

The study showed that, compared to raw solids, single processing methods reduced levels of both mastitis and non-mastitis pathogens, but some pathogens were still detectable in the final product. Farms using anaerobic digestion combined with secondary processing such as composting or drying performed best, with significantly reduced mastitis pathogen counts in RMS bedding and no detection of Salmonella or Mycobacterium avium. Peña-Mosca noted: "Combining digestion systems with secondary processing is more effective than single methods in controlling pathogen risks, which helps reduce the likelihood of disease transmission in dairy farms."

This research provides a reference for producers to evaluate bedding systems. University of Minnesota Professor Sandra Godden stated: "Processing choices affect pathogen levels and ultimately udder health; this study provides important information for producers and veterinarians." The researchers recommend further assessments of seasonal variations and economic benefits to refine the application standards for recycled manure solids bedding.