Genetic correlations of growth, backfat thickness and exterior with stayability in large white and landrace sows

Backfat thickness, daily gain, and five exterior traits were measured in 36 814 Large White and Landrace gilts from nucleus and multiplier herds. Func tional stayability, defined as survived (1) or not (0). from first to secon d (STAY12) and from first to third litter (STAY123) was available for 13 76 0 of these animals in a commercial multiplier environment. Heritabilities a nd genetic correlations of longevity and growth performance and exterior tr aits were estimated by linear models. Heritability estimates for STAY12 and STAY123 in Large White were 0.08 and 0.10, and in Landrace 0.07 and 0.11, respectively. The corresponding genetic standard deviations for STAY123 wer e 0.118 and 0.126 in Large White and Landrace, respectively. Antagonistic g enetic correlations were found between stayability traits and backfat thick ness and daily gain. Estimates ranged from -0.06 to -0.32 for daily gain an d from 0.11 to 0.27 for backfat thickness in both lines. Genetic correlatio ns with leg score were about zero in Large White and positive (from 0.19 to 0.36) in Landrace, whereas genetic relationships with other exterior trait s were near zero. We conclude that the selection for longevity is possible because of high genetic standard deviations of the stayability traits and t hat an antagonism exists between growth performance and longevity, whereas a better leg status decreases involuntary culling. (C) 2000 Elsevier Scienc e B.V. All rights reserved.