if the LRFI pigs were specifically exposed to an undetected infection, an increase in lymphocytes compared to the HRFI line pigs would be expected; the opposite was observed and so there is little evidence that line-specific changes in cell numbers are due to an infection response. Therefore, either lower homeostatic levels of circulating WBC or lowered sensitivity to subacute immune stimuli may explain the lower levels for all WBC types in the LRFI line. The scope of our study does not allow us to conclude which line will perform better after infection because we did not challenge the animals