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Conference abstract, 2012

Successful control of salmonella and a minimized use of antibiotics in Swedish broiler production by long term implementation of disease preventive methods with special reference to the use of competitive exclusion (CE)

Wierup, Martin;


The use of antimicrobials and the isolation of Salmonella are rare events in the Swedish broiler production. This is result of a long term implementation of disease preventive measures as alternatives to antibiotics for health management, in particular in the absence of antimicrobial growth promoters (banned 1986, Wierup 2001), and for the control of Salmonella. Apart from coccidiostats, antimicrobials, was e.g. in 2011 only used in 6 (0.02%) of 3185 commercial broiler flocks (approx.70 mill. birds) and during the last 16 years the average annual incidence of Salmonella infected flocks when tested before slaughter, was 0.2%, and 0.03% of Salmonella contaminated carcasses when tested after slaughter (Anon 2011). The control of Salmonella in food animals was initiated some 60 years ago due to severe Salmonella epidemics including one of world's largest known outbreaks, which 1953 involved more than 9000 sick and the death of 90 persons. Due to similar reasons producers 1970 initiated a specific control for broilers and since 1984 this is mandatory for all producers, who also pay its cost with the aid of insurance. Detailed rules for hygiene and management procedures and testing for Salmonella are formulated and highest demands apply to hatcheries (Anon 2011). Essential elements include prevention of introduction of Salmonella through feed and breeding animals as well as a high level of biosecurity at the farm level, and e.g. during 1982-1988 12 out of 39 (30.8%) flocks of broiler-GP to be imported was found to be Salmonella infected. Since 1972, all broiler feed must be heat treated. HACCP based controls are in place in all feed plants, and corrective actions taken whenever Salmonella is isolated in the weekly samples. Compliance is ensured by bacteriological testing of all flocks 2 weeks before slaughter intended to detect a flock prevalence of Salmonella infected birds of > 5%. If any Salmonella, irrespective of serotype, is detected the flock is destroyed. In addition meat products contaminated by any serovar of Salmonella are since 1971 declared unfit for human consumption. Antibiotic has never been used to control or eliminate Salmonella infections in poultry or other food animals. CE was used during a critical period for the buildup of the current favorable Salmonella status. CE-culture (Broilact®) was found to be a valuable tool in particular to avoid re infection in units where preceding flocks had been Salmonella infected and during periods when the probability for Salmonella contamination of feed was considered as high. During 1981-1990, CE-culture was thus given on arrival of the chicks of 179 flocks (3.82 mill. chickens) in their initial drinking water. Only one of the flocks was found to be Salmonella infected. The virtually Salmonella free status of the hatcheries in Sweden are assumed to be contributing to this good result. However, a specific assessment of the salmonella controlling effect during a period when Salmonella was spread by contaminated feed, demonstrated that the CE-culture had an effect also under these conditions (Wierup et al., 1988). During recent years the CE- culture has been administrated as a spray of chickens directly after hatch to prevent spread of possible Salmonella infection from breeders and interesting studies are underway to assess its possible effect for reducing the spread of Enterobacteriaceae with transmissible resistance against extended-spectrum cephalosporins. References Anon 2010, Surveillance of zoonotic and other animal disease agents in Sweden 2010, . Wierup et al 1998; Poult Sci. 1988 Jul;67(7):1026-33. Wierup 2001; Microb Drug Resist. 2001 Summer;7(2):183-90.


competetive excluion, salmonella, antibiotics

Published in

Book title: International Symposium: Alternatives to Antibiotics (ATA): Challenges and Solutions in Animal Production
Publisher: The World Organisation for Animal Health (OIE)


Int. Symposium Alternatives to Antibiotics in Animal Production;

Authors' information

Associated SLU-program

Animal health (until May 2010)

UKÄ Subject classification

Public Health, Global Health, Social Medicine and Epidemiology
Clinical Science

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