The association between measures of immune competence of boars and survival of their purebred progeny

To test the hypothesis that enhanced immune competence of sires was associated with survival of their progeny, the immune competence of mature boars (N=87) was assessed by measuring both antibody mediated immune responses (AMIR) and cell mediated immune responses (CMIR) to commercial vaccine antigens. Based on results, boars were allocated into tertile groups for AMIR and CMIR, and a combined immune grouping (the concatenation of AMIR and CMIR groups). The association of sire immune group (IG) with independent estimated breeding values (EBVs) for direct (PREd) and maternal (PREm) pre-weaning or post-weaning (POSTd) survival of their progeny was tested. This analysis was performed using EBVs for all boars or only the subset of boars with greater than 200 progeny recorded for survival outcomes. Results demonstrated that there were significant associations between sire IG (P=0.003) or CMIR group (P=0.019) and PREd. As CMIR increased, PREd increased; this improvement was more evident when AMIR group was low. However, when only more accurately evaluated boars were included in the analysis (N=56), grouping on AMIR approached significance for PREd (P=0.104). A significant effect of sire IG for POSTd or PREm was not observed. Results demonstrated that heritable variation in some immune competence measures of sires is reflected in the survival of their progeny. Results also suggested that CMIR phenotype had a greater influence on pre-weaning progeny survival than AMIR in the animals studied; however, selection of animals with a balanced ability to mount both CMIR and AMIR remains an important goal for improving broad-based disease resistance.