Reference | Kaneene2008 (10014)

An intervention study was conducted to determine if discontinuing use of milk replacer medicated with oxytetracycline and neomycin resulted in increased susceptibility to tetracycline in Salmonella, Campylobacter, and E. Coli in dairy calves. The intervention in this study was changing from medicated to non medicated milk replacers on participating dairy farms. The study was divided into two time periods: a 3 month pre-intervention period and a 12 month postinterention period. All herds were sampled monthly prior to intervention and monthly from intervention to the end of the study.

Calves were systematically selected from preweaned female dairy calves on the farm at the day of visit. Healthy cales were sampled before any calves with signs of diarrhea, respiratory disease or other illnes. Fecal samples were collected by placing approximately 10 grams of fecal material obtained by rectal retrieval into Whirl-Pak bags. Environmental samples were collected by swabbing sites with 10 by 10-cm gauze pads soaked in 30mL sterile double-strength skim milk. A composite calf hutch sample was collected by combining individual swabs collected from at least four calf hutches and a composite maternity pen sample was collected by swabbing four areas in the maternity pen.

AST Method: Multiple Methods

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: False