Reference | Rosengren2009 (20018)

A convenience sample of 20 herds was allocated to eight swine veterinarians in Saskatchewan (13 herds) and Alberta (7 herds). Herds were selected by the veterinarians and met the inclusion criteria of having a minimum of 100 sows and of participating in the Canadian Quality Assurance Program (6). Each veterinarian enrolled 2 to 4 herds. At selection, the researchers were blind to antimicrobial use practices in the herds. Study herds were visited once between May and September of 2004. The herd owner or manager provided existing records and completed surveys describing antimicrobial use through feed and water at the production-phase level. For every exposure of suckling, nursery, grow-finish pigs and sows in the previous 12 months, data were collected on the product used, the number of pigs, and the number of days of use. Inventory and management data were also collected (Table 1). Each day antimicrobials were offered was an exposure event. Every herd had an open population, with animals entering and leaving the herd during the previous 12 months. The population at risk was the average number of pigs moved into and out of each phase over this time. This assumed mortality and culls occurred, on average, halfway through each phase. The time at risk was the average number of days spent in each phase. Time-weighted averages accounted for groups of pigs within a phase with different durations at risk. Pigs could be exposed more than once per day, either through products in both feed and water, or through products containing multiple antimicrobials. Antimicrobial use was quantified as the antimicrobial exposure rate and reported for 1,000 or 100,000 pig-days at risk to facilitate interpretation.

During the herd visit, 20 to 25 pens of apparently healthy grow-finish pigs were identified by using a random-numbers table. Feces were collected from the first five pigs observed to defecate and combined into one composite sample per pen. Samples were sent on ice to the Laboratory Services Division, University of Guelph, Guelph, Ontario, for Campylobacter isolation within 24h of collection.

AST Method: None

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: True