Beef × dairy crossbred cattle (n=615) were used to evaluate the effect of pre-harvest indicator traits and genotypes on accuracy of estimated breeding values (EBV) of seedstock candidates for selection. Genotypes for 100,000 single nucleotide polymorphisms (SNP) were provided by the American Simmental Association of purebred and crossbred seedstock animals (n=2,632). Five hundred ninety-five of the 615 beef x dairy cattle had carcass camera and ultrasound data. Phenotypes were not used for any of the seedstock animals even though some may have had performance and ultrasound data. We estimated the genomic relationship matrix among 3,247 animals including both phenotyped and unphenotyped animals. We computed genetic parameters among 37 traits using 666 bivariate restricted maximum likelihood (REML) analyses. Accuracy of EBV depends on heritability. For the sake of brevity, we report accuracy for marbling as a proxy for other traits with similar heritability. We focus on accuracy for marbling because marbling is the primary determinant of carcass value. We computed EBV for all 3,247 animals for marbling based on camera data post-harvest using best linear unbiased prediction (BLUP). We report evidence of overlap in causative genes among postharvest carcass traits; marbling, ribeye area, yield grade, fat thickness, and hot carcass weight (HCW) based on genetic correlations. Genetic correlations range from -0.73 to 0.89. Several live animal traits (frame size, body weight and ultrasound fat thickness and ribeye area) were genetically correlated with post-harvest traits; including hot carcass weight (HCW), ribeye area, yield grade, fat thickness and marbling. Genetic correlations between pre- and post-harvest traits ranged from -0.53 to 0.95. Accuracy for marbling ranged from 0.64 to 0.80 for animals with marbling recorded, and from 0.09 to 0.60 for animals without marbling recorded. Accuracy of animals without phenotypes was related to the genomic relationship between animals with phenotype and those without. Live animal traits were useful for predicting economically important carcass traits based on genetic correlations. Accuracy of EBV for seedstock animals that were not phenotyped were low, but this is consistent with theory, and accuracy is expected to increase with the addition genotypes and carcass data from beef x dairy animals.

中文翻译：

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肉牛与奶牛交配后代胴体性状的遗传参数

肉牛×奶牛杂交牛（n = 615）用于评估收获前指标性状和基因型对候选种子候选育种值（EBV）准确性的影响。100,000 个单核苷酸多态性 (SNP) 的基因型由美国西门塔尔纯种和杂交种畜协会 (n=2,632) 提供。615 头肉牛和奶牛中的 595 头拥有屠体摄像头和超声波数据。尽管某些种子动物可能具有性能和超声数据，但没有对任何种子动物使用表型。我们估计了 3,247 只动物（包括表型动物和非表型动物）之间的基因组关系矩阵。我们使用 666 个二元限制最大似然 (REML) 分析计算了 37 个性状的遗传参数。EBV 的准确性取决于遗传力。为了简洁起见，我们报告大理石花纹的准确性作为具有类似遗传力的其他性状的代理。我们关注大理石花纹的准确性，因为大理石花纹是屠体价值的主要决定因素。我们根据收获后的相机数据，使用最佳线性无偏预测 (BLUP) 计算了所有 3,247 只动物的大理石花纹 EBV。我们报告了收获后胴体性状之间致病基因重叠的证据；基于遗传相关性的大理石花纹、肋眼面积、产量等级、脂肪厚度和热胴体重量 (HCW)。遗传相关性范围为 -0.73 至 0.89。一些活体动物的性状（体型大小、体重、超声脂肪厚度和肋眼面积）与收获后性状存在遗传相关性；包括热胴体重量 (HCW)、肋眼面积、产量等级、脂肪厚度和大理石花纹。收获前和收获后性状之间的遗传相关性范围为-0.53至0.95。对于记录有大理石花纹的动物，大理石花纹的准确度范围为 0.64 至 0.80；对于没有记录大理石花纹的动物，大理石花纹的准确度范围为 0.09 至 0.60。无表型动物的准确性与有表型动物和无表型动物之间的基因组关系有关。活体动物性状可用于根据遗传相关性预测具有重要经济意义的胴体性状。未进行表型分析的种畜动物的 EBV 准确性较低，但这与理论一致，并且随着牛肉 x 奶牛动物的基因型和屠体数据的添加，准确性预计会提高。