Breeding animals are typically raised under high health conditions in nucleus herds, but their offspring are often exposed to multiple disease challenges in commercial production facilities. Because breeding animals are not exposed to many common swine pathogens, it is difficult to select for resilience to disease. A possible solution is selecting for levels of natural antibodies (NAb), which can be measured in a high health environment and in this study are shown to correlate with disease resilience and to be heritable (h2 = 0.11 to 0.39). Therefore, breeding for increased NAb levels in clean conditions could be a valuable method to improve resilience and decrease mortality in market pigs. Work is ongoing to verify the potential of this prediction.