The present invention is directed to method for reducing a population of a targetpathogen in an animal or within a feedlot. The method involves administeringone or more than one controlled release bacteriophage strain or phage component,or both, to the animal, so that the one, or more than one bacteriophage strain isreleased and adsorbs to the one or more than one targetpathogen, thereby reducing the one, or more than one pathogen from the animal.The controlled release bacteriophage strain or phage component may be administeredas a treatment dose prior to further processing of the animal, a treatment dosefollowed by a maintenance dose, or a maintenance dose, to manage feedlot targetpathogens.