Analysis of Veterinary Antimicrobials in Stockpiled Feedlot Manure using LC-ESI/MS/MS

摘要

Veterinary antimicrobials are used in animal production, therapeutically to treat diseases and subtherapeutically to prevent diseases and promote growth. There is a growing concern that environmental contamination by these chemicals may result in widespread bacterial resistance to antimicrobials used in human medicine (Schwartz et al., 2003). The majority of administered antimicrobials (up to 80% or more) is excreted in feces and/or urine either as the parent compounds or their metabolites. Beef cattle manure from confined animal feeding operations can contain veterinary antimicrobials (Cessna et al., 2011; Storteboom et al., 2007) as well as antimicrobial resistant pathogens (Chander et al., 2005) and resistance genes (Storteboom et al., 2007)., all of which are introduced into the environment via runoff from feedlot pens, stockpiled or windrowed manure and manure-amended soil, and via leaching or overflow of lagoons. Veterinary antimicrobials have been detected in manure, manure-amended soil, and surface and ground water resources near large-scale cattle feeding operations (Kim et al., 2010). Dissipation of veterinary antimicrobials is known to occur during aerated windrow composting of beef cattle manure, however, it is unclear if a similar dissipation occurs during stockpiling. The focus of this poster is the analytical methodology used to monitor the dissipation of antimicrobials in stockpiled manure.