The porcine respiratory disease complex (PRDC) is
an increasingly important cause of decreased swine
productivity and is characterized by slow growth, decreased
feed efficiency, anorexia, fever, cough, and
dyspnea. The effects of PRDC are particularly severe
in herds using segregated early weaning because the
onset of disease is delayed until finishing, a more costly
stage of production. Even though many farms have
adopted multiple-site high health programs, the prevalence
of pneumonia on many of these farms has not
declined markedly and instead may be increasing on
some farms.