Chapter Nine: ALL-IN/ALL-OUT PRODUCTION

Most growing/finishing swine facilities have been operated on a continuous basis; that is, they always contain pigs of different ages and weight. Due to the fact that pigs are always present, it is impossible to thoroughly clean, disinfect, or fumigate the environment. It is generally assumed that the common air space shared by pigs of various age groups allows for both clinical and subclinical diseases to be more prevalent and be transmitted easily in these types of facilities. As an example, studies have shown that as many as 70% of the hogs slaughtered have signs of enzootic pneumonia.