Epidemiological evaluation of the salmonella-controlling effect of a nationwide use of a competitive exclusion culture in poultry.

The purpose of the study was to evaluate the salmonella contamination-controlling effect of a nationwide use of a competitive exclusion culture in poultry. During a 5-yr period, a bacterial flora from caecum of adult birds was given to broiler chickens in order to control salmonella infection. The culture was given on 144 occasions to a total of 2.86 million chickens. The base for the evaluation was the compulsory and regular control for salmonella contamination conducted according to the salmonella control program applied to Sweden. Epidemiological evaluation, especially in relation to the use of the culture during a period when salmonella was spread from a feed factory, strongly supports the conclusion that the culture has a salmonella contamination-preventing effect under field conditions, as earlier had been found in laboratory studies. Questionnaires answered by producers did not indicate significant adverse effects of the treatment.