Risk factors for hazard of release from Salmonella-control restriction on Swedish cattle farms from 1993 to 2002

There was a lower hazard for release from salmonella control restrictions after the European Union (EU) accession in 1995, and/or change of testing from one to two negative herd tests for release of restrictions (hazard ratio (HR) = 0.56, 95% confidence interval (CI) = 0.38, 0.84), for every additional number of 100 cows (HR = 0.83; CI = 0.7, 0.97), if rodents and/or wild birds were abundant (HR = 0.5, CI = 0.27, 0.98) and if there was more than one farm site in the company (HR = 0.47, CI = 0.28, 0.81).