Estimation of maternal effects on the North-Iranian native chicken traits using Bayesian and REML methods
2013
Yousefi Zonuz, A., University of Tabriz, Tabriz (Iran) | Alijani, S., University of Tabriz, Tabriz (Iran) | Rafat, S. A., University of Tabriz, Tabriz (Iran) | Abbasi, M. A., Animal Science Research Institute of Iran, Karaj (Iran) | Daghigh Kia, H., University of Tabriz, Tabriz (Iran)
In the present research, direct and maternal genetic parameters were estimated for 4 productive and reproductive traits of Iranian native chickens. Six different animal models with restricted maximum likelihood (REML) and Bayesian procedure were applied to estimate genetic parameters. The chickens were investigated considering their phenotypic and genotypic trend after 19 generation selection. Estimated direct and maternal heritability is based on best models using REML methods: 0.55, 0.01 for average egg weight; 0.22, 0.009 for body weight at 8 weeks old; 0.15, 0.02 for egg number and 0.39, 0.045 for age at sexual maturity, respectively. The estimated values of these parameters using Bayesian approach for studied traits are based on best model: 0.54, 0.034 for average egg weight, 0.23 and 0.044 for body weight at 8 weeks old, 0.15, 0.02 for egg number and 0.41, 0.048 for age at sexual maturity, respectively. In this study, the results obtained from the statistical REML method are similar to that of Bayesian approach, but there are differences between the traits regarding the selection of best model due to different ways of models evaluation. The result of genetic trend regarding average egg weight, body weight at 8 weeks old, egg number and age at sexual maturity were -0.100 (g), 5.650 (g), 0.721 (number) and -1.558 (day), respectively. Correlation of the direct and maternal genetic effects (ram) for studied traits was estimated. Consequently, a negative correlation between maternal and direct additive genetic effects was observed.
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