Introduction: Seasonal effects on fertility in gilts and sows are characterised by reduced reproductive performance during the summer and autumn period (Love et al., 1993). Both the number born alive (NBA) and farrowing rate (FR) are affected by seasonal infertility. Economic values (EV) for these traits depend on assumed production parameters, cost parameters (Amer et al., 2014) and mean performance in FR (Hermesch, 2021), which consequently are influenced by seasonal effects. Both NBA and FR were genetically different traits between seasons or environments based on temperature groupings (Lewis and Bunter, 2011; Bunz et al., 2019). Both may be considered as different traits in the most challenging season (summer) versus the other seasons. The hypothesis of this study was that by considering the economic implications of seasonal effects in sow breeding objectives (BO), the relative emphasis placed on traits changes.