under conditions of reduced food availability on porcine immune cell numbers has been reported whereas 1 study has been published on the effect of selection for RFI on response to a sustained inflammatory stimulus therefore, the effect of selection for RFI on how pigs perceive and deal with immune challenges has been poorly investigated. Therefore, the objectives of this study were to determine the effect of selection for RFI in pigs on complete blood count (CBC) traits, to estimate the heritability of CBC traits under RFI selection, and to determine if peripheral blood cell profiles measured early in life can be used to predict RFI later in life.