【摘要】 【目的】西门塔尔牛与荷斯坦牛杂交（西×荷杂交）是培育高效乳肉兼用牛群的有效方式，我国部分地区利用该品种间杂交模式已获得了一定规模的杂交群体。为了建立用于准确评估西×荷杂交牛血统组成的方法，【方法】本研究以荷斯坦牛、西门塔尔牛、挪威红牛等3个品种为纯种参考群体，利用基于基因组SNP标记的遗传混合分析方法，对161头西×荷杂交牛的血统比例进行估计。【结果】杂交一代（西门塔尔牛×荷斯坦牛）的荷斯坦牛血统为41.80%±9.00%，西门塔尔牛血统为52.59%±10.38%。杂交二代（包括杂交一代回交荷斯坦牛、杂交一代回交西门塔尔牛）的荷斯坦牛血统估计分别为80.01%±6.68%和17.20%±4.43%，西门塔尔牛血统估计分别为17.01%±7.83%和81.80%±4.62%，在部分杂交个体中检出一定比例的挪威红牛血统。【结论】估计的血统比例接近理论值（杂交一代1∶1，杂交二代3∶1），且与该群体的杂交历史相符，表明此方法可以准确评估杂交牛的遗传背景，为今后有效监测杂交牛群的血统组成和实施精准选育奠定了技术基础。更多还原

【Abstract】 【Objective】The strategy of crossbreeding Simmental with Holstein cattle(Simmental×Holstein) has been identified as an effective approach for enhancing dairy herd efficiency. In some parts of China, a certain scale of hybrid population has been obtained by using the crossbreeding model in various regions of China. The aim of this study is to establish a precise methodology for assessing the ancestry composition of Simmental-Holstein crossbreeding cattle.【Methods】Leveraging Holstein, Simmental, and Norwegian Red cattle as purebred reference populations, this study employed genomic SNP markers and admixture analysis to estimate the ancestry proportions of 161 Simmental-Holstein crossbreeding cattle.【Results】 The results showed that the first-generation hybrids(Simmental×Holstein) comprised approximately 41.80% ± 9.00% Holstein and 52.59% ± 10.38% Simmental ancestries. For the secondgeneration hybrids, including backcrosses to both Holstein and Simmental, the estimated ancestries were80.01% ± 6.68% and 17.20% ± 4.43% for Holstein, and 17.01% ± 7.83% and 81.80% ± 4.62% for Simmental, respectively. Notably, a fraction of the hybrid individuals exhibited a certain proportion of Norwegian red cattle ancestry.【Conclusion】The estimated ancestry proportions are close to the theoretical values(1??1 for the first generation, 3??1 for the second generation) which is align with the hybridization history of the population, indicating that this method can accurately assess the genetic background of crossbreeding cattle. This findings lay a solid technical foundation for effectively monitoring the ancestry composition of crossbreeding cattle herds and implementing precise selection and breeding strategies in the future.更多还原