Antibody Tests for Identification of Mycobacterium bovis-Infected Bovine Herds

Antibody in sera from 560 cattle of tuberculosis (TB)-infected and TB-free herds was investigated by competition and indirect enzyme-linked immunosorbent assays using bovine purified protein derivative tuberculin as the antigen. Antibody was detected in sera from both types of herd, with a widely overlapping range of titers. However, a “tail” of high-titered sera was observed for the distribution of data for only those cattle from TB-infected herds.