Genetic Eveluation And Genetic Parameter Estimation In Aohan Merino Sheep Using BLUP And MTDFREML

The study analyzed the non-genetic factors influencing the main traits of Aohan Merino Sheep, selected different models and estimated variance components and genetic parameters of twelve traits using animal model Best Linear Unbiased Prediction(BLUP) and Multiple Trait Derivative-Free Restricted Maximum Likelihood(MTDFREML). The results were showed as follows:Herd and Birth year or measurement year of traits almost had significant effect on all the traits. Sex had significant effect on all the early traits. Birth type significantly affected all the early traits except one-age live weight. AGD only significantly affected birth weight and weaning litter weight. Age had significant effect on all the wool traits except wool density score and wool oil score.After selecting different models, Model (1) was fit to estimate one-age live weight, weaning litter wool length and weaning litter wool fineness. Model (4) was fit to estimate birth weight and weaning litter weight. Model (5) was fit to estimate wool yield, live weight and wool length. Model (7) was fit to estimate wool fineness, wool bend score, wool density score and wool oil score.In the early traits, the estimated heritabilities of birth weight, weaning litter weight, one-age live weight, weaning litter wool length and wool fineness were 0.21, 0.21, 0.10, 0.14, 0.10.The estimated genetic correlations of these traits were respectively 0.44, 0.02, 0.27, 0.27, 0.64, 0.35, -0.24, 0.01, -0.06, 0.07. In the wool traits, the estimated heritabilities of wool yield, live weight, wool length, wool fineness, wool bend score, wool density score and wool oil score were 0.12, 0.12, 0.16, 0.12, 0.08, 0.05, 0.05.The estimated genetic correlations of these traits were respectively 0.32, 0.50, -0.30, 0.50, 0.25, 0.12, -0.01, 0.05, 0.46, -0.17, -0.26, -0.40, 0.37, 0.09, 0.00, 0.51, 0.06, 0.01, 0.24, 0.00, 0.11. The ranks of all kinds of one-trait estimated breeding values were basely same to comprehensive estimated breeding value. And all the genetic evaluation methods had significant correlations.