新疆褐牛不同生长阶段体尺体重的遗传参数估计

试验旨在构建新疆褐牛不同生长阶段体尺体重性状的遗传参数估计模型，估计新疆褐牛生长发育性状的遗传参数，为新疆褐牛育种目标性状的确定和综合选择指数的制定提供理论依据。以1983－2017年收集的4个新疆褐牛核心育种场81头公牛后代的2 504条新疆褐牛体尺体重数据为研究材料，以初生及6、12和18月龄阶段的体重、体高、体斜长和胸围性状为研究对象，通过DMU软件构建多性状动物模型，以场、出生年份、出生季节和性别为固定效应，以加性效应和母体效应为随机效应，估计各性状的遗传力和遗传相关。结果显示，新疆褐牛初生至18月龄阶段体重遗传力估计值为0.22~0.61，体高遗传力估计值为0.43~0.46，体斜长遗传力估计值为0.29~0.52，胸围遗传力估计值为0.35~0.61。相同和不同生长阶段新疆褐牛各体尺体重性状间均呈现正的遗传相关和表型相关，其中相同生长阶段各体尺体重性状间的遗传相关系数为0.11~0.92，表型相关系数为0.05~0.92；不同生长阶段各体尺体重性状间的遗传相关系数为0.08~0.92，表型相关系数为0.01~0.72。18月龄与其他各生长阶段间体尺体重性状的遗传相关系数较高，且均属于中高遗传力性状。因此，在制定新疆褐牛综合选择指数时，应重点考虑18月龄阶段的体尺体重性状，从而进一步提升新疆褐牛生长发育性状的遗传进展。

Estimation of Genetic Parameters of Body Size and Body Weight in Xinjiang Brown Cattle at Different Growth Stages

This study was aimed to construct the genetic parameter estimation model of body size and body weight traits in Xinjiang Brown cattle at different growth stages and estimate the genetic parameters of growth and development traits in Xinjiang Brown cattle, in order to provide a theoretical basis for the determination of breeding target traits and the formulation of comprehensive selection index in Xinjiang Brown cattle. DMU software was used to build multi-trait animal models by taking the body size and body weight data of 2 504 Xinjiang Brown cattle of the progenies of 81 bulls from four Xinjiang Brown Cattle core breeding farms collected from 1983 to 2017 as research materials, taking the body weight, body height, body oblique length and chest circumference at birth, and 6, 12 and 18 months of age as the research objects, and estimate the heritability and genetic correlation of traits by taking field, birth time, birth season and sex as fixed effects, and additive effect and maternal effect as random effects. The results showed that the value of estimated body weight heritability of Xinjiang Brown cattle from birth to 18 months of age was from 0.22 to 0.61, the value of estimated body height heritability was from 0.43 to 0.46, the value of estimated body oblique length heritability was from 0.29 to 0.52, and the value of estimated chest circumference heritability was from 0.35 to 0.61. There were positive genetic correlation and phenotypic correlation among body size and weight traits at the same and different growth stages, the genetic correlation coefficient between different body size and body weight traits at the same growth stage was from 0.11 to 0.92, and the phenotypic correlation coefficient was from 0.05 to 0.92. The genetic correlation coefficient between different body size and body weight traits at different growth stages was from 0.08 to 0.92, and the phenotypic correlation coefficient was from 0.01 to 0.72. The genetic correlation coefficient of body size and body weight traits between 18 months of age and other growth stages were high, both of which belong to middle and high heritability traits. Therefore, in order to further improve the genetic progress of the growth and development traits of Xinjiang Brown cattle, we should pay more attention to body size and body weight at 18 months of age when formulating the comprehensive selection index of Xinjiang Brown cattle.