were used to test for the presence of serum antibodies against M. hyopneumoniae prior to challenge. Animals were found to be negative by all tests. The procedures used for the challenge varied according to previous studies and are listed in Table 1.
were used to test for the presence of serumantibodies against M. hyopneumoniae prior to challenge.Animals were found to be negative by all tests. Theprocedures used for the challenge varied according toprevious studies and are listed in Table 1.