Inner Mongolia cashmere goat is an excellent livestock breed formed through long-term natural selection and artificial breeding, and is currently a world-class dual-purpose breed producing cashmere and meat. Multi trait animal model is considered to significantly improve the accuracy of genetic evaluation in livestock and poultry, enabling indirect selection between traits. In this study, the pedigree, genotype, environment, and phenotypic records of early growth traits of Inner Mongolia cashmere goats were used to build multi trait animal model., Then three methods including ABLUP, GBLUP, and ssGBLUP wereused to estimate the genetic parameters and genomic breeding values of early growth traits (birth weight, weaning weight, average daily weight gain before weaning, and yearling weight). The accuracy and reliability of genomic estimated breeding value are further evaluated using the five fold cross validation method. The results showed that the heritability of birth weight estimated by three methods was 0.13-0.15, the heritability of weaning weight was 0.13-0.20, heritability of daily weight gain before weaning was 0.11-0.14, and the heritability of yearling weight was 0.09-0.14, all of which belonged to moderate to low heritability. There is a strong positive genetic correlation between weaning weight and daily weight gain before weaning, daily weight gain before weaning and yearling weight, with correlation coefficients of 0.77-0.79 and 0.56-0.67, respectively. The same pattern was found in phenotype correlation among traits. The accuracy of the estimated breeding values by ABLUP, GBLUP, and ssGBLUP methods for birth weight is 0.5047, 0.6694, and 0.7156, respectively; the weaning weight is 0.6207, 0.6456, and 0.7254, respectively; the daily weight gain before weaning was 0.6110, 0.6855, and 0.7357 respectively; and the yearling weight was 0.6209, 0.7155, and 0.7756, respectively. In summary, the early growth traits of Inner Mongolia cashmere goats belong to moderate to low heritability, and the speed of genetic improvement is relatively slow. The genetic improvement of other growth traits can be achieved through the selection of weaning weight. The ssGBLUP method has the highest accuracy and reliability in estimating genomic breeding value of early growth traits in Inner Mongolia cashmere goats, and is significantly higher than that from ABLUP method, indicating that it is the best method for genomic breeding of early growth weight in Inner Mongolia cashmere goats.
内蒙古绒山羊是经过长期自然选择和人工选育后形成的优良家畜品种，是目前世界一流的绒肉兼用山羊。多性状动物模型被认为可以显著提高畜禽遗传评估的准确性，实现性状间的间接选择。本文基于内蒙古绒山羊个体的系谱、基因型、环境以及早期生长性状的表型记录，建立多性状动物模型，利用ABLUP、GBLUP、ssGBLUP三种方法进行早期生长性状(初生重、断乳重、断乳前平均日增重、周岁重)遗传参数及基因组育种值的估计，进一步利用五倍交叉验证方法评价基因组育种值估计准确性和可靠性。结果显示，3种方法估计的初生重遗传力为0.13~0.15，断乳重遗传力为0.13~0.20，日增重遗传力为0.11~0.14，周岁重遗传力为0.09~0.14，均属于中等偏低遗传力；断乳重和日增重、日增重和周岁重之间存在强的正遗传相关，相关系数分别为0.77~0.79和0.56~0.67，表型相关发现同样的规律；ABLUP、GBLUP和ssGBLUP法估计的初生重育种值准确性分别为0.5047、0.6694、0.7156，断乳重分别为0.6207、0.6456、0.7254；日增重分别为0.6110、0.6855、0.7357，周岁重分别为0.6209、0.7155、0.7756。综上所述，内蒙古绒山羊早期生长性状属于中等偏低遗传力，对其进行遗传选育改良速度相对较慢；通过对断乳重的选择可以实现其他生长性状的遗传改良；ssGBLUP方法估计内蒙古绒山羊早期生长性状基因组育种值的准确性和可靠性均最高，且显著高于ABLUP法，说明该方法是内蒙古绒山羊早期性状基因组选育的最佳方法。.
Keywords: Inner Mongolia cashmere goat; accuracy of genomic estimated breeding value; early growth traits; multi trait animal model.