Pathogen reduction and factors responsible for pathogen reduction in dairy farm operations treating dairy manure.

摘要

Manure management at large dairy operations presents a challenge; there is an increasing interest among farm managers for reuse of their manure and other farm residuals as low-cost bedding materials. A significant barrier preventing more widespread adoption of this technology is ambiguity in regards to the presence of disease-causing agents that may sicken animals and reduce farm milk production. In this study, pathogen reduction was correlated to the operational parameters of different manure management techniques at three different dairy farms in northern New York State. Two log order reductions of Campylobacter, Enterococcus, Klebsiella, and fecal Bacteroidetes concentrations were achieved during composting or mesophilic anaerobic digestion of organic material. Effluent concentrations for the specific pathogens ranged between 1E3 to 1E2 g-1 dry solids and 1E6 g-1 dry solids for fecal Bacteroidetes for both treatment systems. Bacterial concentrations in freestall barn bedding was lowest for the farm using clean sand only, followed by the farm that recycles bedding sand after sand separation, and the farm that uses bedding with composted manure solids. Pathogen concentrations were strongly correlated to moisture content, volatile solids content, and sample type (organic versus inorganic samples).