his study estimates heritability of complete blood count (CBC) and in vitro immunoassay traits. The traits were measured from blood samples of young-healthy nursery animals that then survived to slaughter during a natural polymicrobial disease challenge in the grow-to-finish stage but had variable production performance. Genetic correlations of CBC and immunoassay traits with performance traits collected from grow-to-finish pigs exposed to the challenge were also estimated, including carcass, average daily gain, and feed intake traits. Most CBC and several immunoassay traits had heritability estimates ranging from 0.11 to 0.46. Several CBC and immunoassay traits showed moderate to high positive (0.25 to 0.51) or negative (-0.92 to -0.37) genetic correlations with performance traits under disease. These results suggest that some CBC and immunoassay traits collected from young-healthy animals before exposure to disease challenge are potential indicator traits for selecting disease resilient pigs that can maintain better performance under pathogen exposure.