Study Of Genetic Evaluation Model And Estimation Of Genetic Parameters Of Growth Traits In White Cashmere Goats

In order to study the characteristics of Inner Mongolia White Cashmere goats growth, test using the data from1998to2011weight performance records of Inner Mongolia White Cashmere goats, divided into complete (Birth weight to weight at the age of7) and partial (Birth weight to weight at the age of2) data, divided into group average and average level, using nonlinear regression (Logistic, Gompertz, Von Bertalanffy and Mitscherlich common growth curve model) to simulate the growth of White Cashmere goats. Results show that under the partial data and group average, with Mitscherlich model for early growth White Cashmere goats had better fitting effect; Von Bertalanffy calculated daily gain maximum is231g, inflection point weight is10.1876kg, inflection point day is50d. That instructs that early breeding and breeding management is based on it.By establishing the random regression model, using univariate analysis, nested third-order Legendre polynomial, choose fixed effects. Fixed effects include groups, types of birth, gender, birth years and measure years. By comprehensive comparison of logarithmic likelihood ratio, residual variance, AIC and BIC information standard, choose fixed effects of fitting growth trait.Fitting the fixed and random effects (additive genetic effects and permanent environmental effects) with different orders of legendre polynomial, using the evaluation of likelihood ratio and residual variance from different model such as the comprehensive evaluation index to select optimal genetic evaluation model for growth trait. Then the optimal model for growth trait were applied to analyze the characters of phenotypic and genetic variation. The study obtained;Groups, types of birth, gender, birth years and measure years affected very significantly on the weights; the optimal genetic evaluation model for growth trait were:LP8-8-7.Phenotypic correlation of weight is0.032～0.759,there were weak negative correlation for1th day and431th,1155th day, were0.032and0.003,but,there were strong positive correlation for1892th day and1155th,2674th day, were0.700and 0.759; genetic correlation were0.041-0.921,there were weak positive correlation for431th day and1th day, were0.041,there were strong positive correlation for1155th day and1892th,2674th day, were0.921and0.876,there were strong positive correlation for1892th day and2674th day, were0.871; heritability reduced with the increase of number of days after the first increase, then increased. The heritability of1th day were minimum, were0.041. The heritability of2674th day were highest, were0.553.