Studies of G×E for longevity traits are scarce. Haile-Mariam et al. (2008) showed high genetic correlations (>0.9) for survival to second lactation between different calving systems or regions in Australia, whereas Forabosco et al. (2009) showed that genetic correlations between Interbull member countries range from 0.49 to 0.76 for Holstein and from 0.30 to 0.96 for Red Dairy cattle. However, these genetic correlations differed from unity not only because of G×E interactions but also because of differences in trait definitions and weak genetic ties between countries.