Genetic parameters for body weight and egg production traits in Taiwan native chicken homozygous for the heat shock protein 70 gene

Taiwan nativechickenstrain (Taishu No. 7)carryinghomozygous gene for heat shock protein 70 (HSP70) was evaluated forheritability,genetic and phenotypic correlations for body weight at birth (BW0), body weight at 16 weeks of age (BW16), egg weight at first egg (FEW), body weight at first egg (BWFE), age at first egg (AFE) and number of eggs laid up to 40 weeks of age (EN40) in female chickens. The multivariate animal model using the residual maximum likelihood procedure wasapplied. The estimations realized over three generations and the pedigree file was composed of 141 individuals. Heritability estimates of BW0, BW16,FEW,AFE,BWFE,and EN40 were 0.306, 0.763, 0.071, 0.284, 0.681, and 0.200, respectively.The body weight traits showed that the BW16 had the negative genetic correlations with BW0, AFE, and EN40 (rg= –0.061; rg= –0.242; rg= –0.087), but had the positive genetic correlations with FEW and BWFE (rg=0.419; rg=0.945). The egg production traits showed that the EN40 had the negative genetic correlations with BW16 and AFE (rg= –0.087; rg= –0.195), but had the positive genetic correlation with BW0, FEW, and BWFE (rg= 0.336; rg= 0.039; rg=0.182). Based on the results of this study, the BWFE could be introduced as a suitable indirect selection criteria for improving egg production because of the higher heritability and a positive genetic correlation with egg production.