Impacts on water quality before and after water line cleaning and disinfection with peracetic acid in swine farms.

While it is well recognized that maintaining good water quality is a cornerstone of swine husbandry, research on its role in swine health, performance, and management remains limited. This study evaluated the impacts on water quality after a 0.78% peracetic acid administration in water lines for 24 h between groups of pigs to remove water line mineral scale and biofilm. A secondary objective of the study was to evaluate if there were water quality differences between the water sample location (well source vs. rooms). Six, wean-to-finish swine farms in Iowa sourcing water from on-site wells were enrolled in the study and water samples were collected pre-treatment (0), post-treatment (1), and 3, 5, 7, 14, 21, 42, 56, and 77 d post-treatment. Water samples were tested for minerals, nitrate, sulfate, total dissolved solids, on-farm temperature, on-farm and in-lab pH, total coliforms and E. coli. Study results demonstrated that most chemical water quality parameters (calcium, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium) were not significantly different over sample collection dates, sample locations, and the interaction terms. Total coliforms, total dissolved solids, zinc, on-farm and in-lab pH, and water temperature displayed significant differences. This study showed that total coliforms were not statistically significant pre-and post-treatment with a one-time application of 0.78% peracetic acid for 24 h, and that total coliforms numerically peaked and reached the upper reporting limit at 7 d post-treatment in rooms. Total coliforms were significantly different between sample locations (well source vs. room water lines), with room water lines having greater total coliform counts. These results demonstrate that an application of 0.78% of peracetic acid does not significantly impact most chemical water quality parameters post-treatment. Water sample location demonstrated significant differences in microbial water quality, with rooms water samples having significantly greater total coliforms than well collected samples. This demonstrates that water line biofilms are potentially contributing to decreased water quality in farms. Room vs. well differences were appreciated for total dissolved solids, on-farm and in-lab pH, and water temperature. This research provides further water sampling guidance considering multiple locations and provides additional insights into water line management strategies in swine farms.