Reference | Rollo2010 (20017)

Cross-sectional. The present study included 95 farms in the Midwestern United States, including Iowa (n = 37), Illinois (15), Indiana (5), Michigan (21), Minnesota (8), Nebraska (6), Ohio (2), and Wisconsin (1). Sixty farms were managed under conventional swine farm practices, and 35 farms were considered antimicrobial-free facilities. The production systems that were classified as antimicrobial-free had not used antimicrobial drugs for a minimum of 1 year prior to enrollment in the study. Antimicrobial-free farms were selected from membership lists of 2 cooperatives; conventional farms were selected on the basis of close geographic proximity to the antimicrobial-free farms, or the number of slaughter pigs produced per year.17 The total number of pigs marketed per year was used as a surrogate for herd size.

Samples of feces were collected from 15 pigs on each farm with the exception of 1 farm, where only 12 pigs were available for sample collection. Collection of feces from individual pigs on farms has been previously described.17 Briefly, farms were visited once in 2002 or 2003, and samples were collected only from healthy pigs. Approximately 5 g of fresh fecal material/pig was collected and placed in a tube containing Cary-Blair transport medium.a The specimens were sent on ice to the National Food Safety and Toxicology Center, Michigan State University, and plated within 48 hours of collection.

AST Method: None

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: True