The invention is related to methods and compositions for reducing protozoa populations in animals. In an embodiment, the invention includes a method for reducing protozoal populations including administering a first composition comprising an effective amount of saponins to the animal, and administering a second composition comprising an effective amount of a preservative to the animal. In an embodiment, the invention includes a method for killing protozoa comprising contacting protozoa with a composition comprising an effective amount of saponins and an effective amount of ethoxyquin. Other embodiments are included herein.