Detection of Mycoplasma hyopneumoniae antibodies in porcine serum by complement-fixation test

A total of 660 porcine serum samples from 35 herds in 6 states were tested for complement-fixing antibodies against Mycoplasma hyopneumoniae. Samples were prepared from blood collected from swine herds suspected of having mycoplasmal pneumonia because of clinical signs or lesions or both. Only 56 serums from 10 herds gave positive test results.