SMG9基因拷贝数变异和不同因素对奶牛繁殖性状的影响

Effects of SMG9 gene copy number variation and other different factors on reproductive traits in dairy cattle

旨在分析不同因素和SMG9基因拷贝数变异对奶牛繁殖性能的影响,以期为提升奶牛繁殖性能和探究SMG9基因拷贝数功能提供参考。收集河南某牛场200头已孕奶牛的配种次数、产犊后首次配种天数和空怀天数等繁殖性状数据,统计父亲、年龄、胎次、配种员和配种季节等因素,并通过荧光定量PCR法鉴定每头牛SMG9基因的拷贝数类型。通过一般线性模型将SMG9基因的拷贝数类型与繁殖性状进行关联分析,并分析不同因素对繁殖性能的影响。结果:父亲、年龄、胎次、配种季节和SMG9拷贝数变异会显著影响该奶牛群体的繁殖性状(P<0.05)。其中:1胎牛配种次数显著高于2胎牛,秋季配种次数显著高于春季和冬季(P<0.05),冬季产犊后首次配种天数高于秋季(P=0.064),1胎的空怀天数显著高于2胎(P<0.05)。SMG9基因的拷贝数变异与配种次数和空怀天数显著相关(P<0.05),多拷贝型个体繁殖性能优于正常型和缺失型。研究结果可为牛繁殖性能提升提供参考,并提示SMG9基因的拷贝数可作为奶牛繁殖性能选育的分子标记。

The aim of this study was to investigate the effects of SMG9 gene copy number variation(CNV)and other different factors on the reproductive traits in dairy cattle,with a view to providing reference for improving the reproductive performance of cows and exploring the function of the SMG9 CNV.Three reproductive traits and several environmental factors of 200 pregnant cows in a cattle farm in Henan Province were observed.SMG9 CNV of each cow was identified using the qPCR method.Association analysis between SMG9 CNV and the reproductive traits was performed using a linear model.The influence of the other factors on the reproductive traits was analyzed as well.The results showed that the factors of sire,age,parity,breeding season and SMG9 CNV significantly affected the reproductive traits in this cow population(P<0.05).The number of insemination was significantly higher in the individuals in the first lactation than that in the second lactation,and significantly higher in autumn than that in spring and winter(P<0.05).Days of first mating after calving were more in winter than that in autumn(P=0.064).The number of days open in the first lactation were significantly higher than that in the second lactation(P<0.05).SMG9 CNV was significantly associated with the number of insemination and the number of days open in this population.The individuals of the duplication CNV type showed better reproductive performance than the individuals of the other two CNV types.The results of the present study provided reference for the farm to take measures to improve reproductive performance of cows,and suggested that the SMG9 CNV might be used as a candidate molecular marker for selection of the reproductive traits in dairy cattle.