Genetic parameters and correlations for female reproductive performance and early growth performance of piglets in Landrace breed across various regions of Vietnam

This study aimed to estimate the genetic parameters for reproductive and early performance traits in Vietnam-purebred Landrace pigs. Traits analysed included the total number of pigs born (TB), number of pigs born alive (NBA), number of weaned pigs (NW), individual birth weight (BW), litter birth weight (LBW), individual weaning weight (WW), and litter weaning weight (LWW). This analysis was based on 5294 farrowing records collected from 2013 to 2019 from 1500 Landrace sows across three locations in Vietnam. Genetic parameters were estimated using ASReml-R. Heritability estimates for reproduction traits were negligible, below 0.10, ranging from 0.019 +/- 0.012 to 0.071 +/- 0.014, with repeatability ranging from 0.019 +/- 0.014 to 0.152 +/- 0.016. The genetic correlations ranged from -0.788 +/- 0.09 to 0.993 +/- 0.163, with the highest between IBW and LWW and the lowest between TB and IBW. NBA showed positive and moderate to high correlations with other traits, except for a negative correlation with IBW. Phenotypic correlations among reproductive traits ranged from -0.42 +/- 0.013 to 0.879 +/- 0.004. Negative phenotypic correlations were observed between TB, NBA, and NW with IBW and IWW, while positive correlations were observed with LBW and LWW. In conclusion, the heritability for reproductive performance and early growth traits in Vietnam-purebred Landrace pigs is negligible, indicating limited genetic progress from direct selection.