A method for reducing the population of pathogenic bacteria in an animal being reared in an animal rearing facility is provided. The method involves using one or more than one naturally-occurring location-specific bacteriophages selected to be highly specific to the strains of the one or more than one pathogen present in the facility, a phage component derived from the one or more than one naturally- occurring location-specific bacteriophages, or a combination thereof, to produce a location-specific bacteriophage preparation. The preparation is administered to the animal, to reduce the one or more than one pathogenic bacteria. The method may also involve a step of identifying location-specific isolates of the one or more than one pathogenic bacteria at or near the animal rearing facility.
