Longevity and lifetime reproductive trait genetic parameter estimates from Thai Landrace and Large White pig populations.

The objective of this study was to estimate genetic parameters for age at first farrowing (AFF), length of productive life (LPL), lifetime number of piglets born alive (LNBA), lifetime number of piglets weaned (LNW), lifetime wean to first service interval (LW2S), and lifetime pig efficiency (LTP365) from commercial Thai Landrace and Large White populations. Data from 12,843 Landrace (LR) and 14,757 Large White (LW) sows in a Thai commercial pork production system were utilized in this study. The genetic parameters for each trait were estimated using the average information restricted maximum likelihood algorithm where a multivariate animal model was implemented. Heritability estimates for AFF and LPL were low for LR (0.11 and 0.02, respectively) and LW (0.19 and 0.07, respectively). Heritability estimates for lifetime traits ranged from 0.01 to 0.05 for LR and 0.04 to 0.09 for LW. The genetic correlation between LPL with LNBA, LNW, LW2S and LTP365 were positive for LR (0.39 to 0.90) and LW (0.59 to 0.94). Favourable genetic correlations were observed between AFF and LPL for LR (- 0.14) and LW (- 0.14). The phenotypic correlations between LPL and lifetime traits ranged from 0.64 to 0.92 for LR and 0.61 to 0.91 for LW. Favourable phenotypic correlation between AFF and lifetime production traits was observed in the present study. The estimated heritability for the length of productive life and lifetime traits was relatively lowly heritable; length of productive life is genetically associated with lifetime traits. These findings indicate that sow lifetime productivity could be improved using selection on LPL and AFF without antagonism. Thus, improving sow lifetime productivity in the commercial pork production system, AFF and LPL should be included in a maternal line genetic evaluation programme.