We investigated the applicability of ssGBLUP methodology under the autoregressive model (H-AR) for genomic evaluation of longitudinal reproductive traits in Portuguese Holstein cattle. The genotype data of 1,230 bulls and 1,645 cows were considered in our study. The reproductive traits evaluated were interval from calving to first service (ICF), calving interval (CI) and daughter pregnancy rate (DPR) measured during the first four parities. Reliability and rank correlation were used to compare the H-AR with the traditional pedigree-based autoregressive models (A-AR). In addition, a validation study was performed considering different scenarios. Higher genomic estimated breeding values (GEBV) reliabilities were obtained for genotyped bulls when evaluated under the H-AR model, with emphasis on bulls with less than 9 daughters. For this group, the averages of GEBV reliabilities corresponded to 0.62, 0.69 and 0.62 for ICF, CI and DPR, respectively, while the averages obtained by the A-AR model were 0.27, 0.15 and 0.16. The validation study was favourable to H-AR. The best results were observed in the scenario where genotyped cows were combined with contributing bulls (genotyped bulls with daughter or relationship information in the population). Overall, the results suggest that ssGBLUP methodology under the autoregressive model is a feasible and applicable approach to be used in genomic analyses of longitudinal reproductive traits in Portuguese Holstein cattle.

中文翻译：

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葡萄牙荷斯坦牛纵向生殖性状基因组评估的自回归单步模型

我们研究了 ssGBLUP 方法在自回归模型 (H-AR) 下对葡萄牙荷斯坦牛纵向繁殖性状进行基因组评估的适用性。我们的研究考虑了 1,230 头公牛和 1,645 头奶牛的基因型数据。评估的繁殖性状是从产犊到第一次服务的间隔（ICF）、产犊间隔（CI）和在前四胎期间测量的子代妊娠率（DPR）。使用可靠性和等级相关性将 H-AR 与传统的基于谱系的自回归模型 (A-AR) 进行比较。此外，还考虑了不同的情况进行了验证研究。在 H-AR 模型下评估时，基因分型公牛获得了更高的基因组估计育种值 (GEBV) 可靠性，重点是少于 9 个女儿的公牛。对于这个群体，对于 ICF、CI 和 DPR，GEBV 可靠性的平均值分别对应于 0.62、0.69 和 0.62，而 A-AR 模型获得的平均值分别为 0.27、0.15 和 0.16。验证研究有利于 H-AR。在基因分型母牛与贡献公牛（基因分型公牛与子代或种群中的关系信息）结合的情况下观察到最好的结果。总体而言，结果表明自回归模型下的 ssGBLUP 方法是一种可行且适用的方法，可用于葡萄牙荷斯坦牛纵向繁殖性状的基因组分析。在基因分型母牛与贡献公牛（基因分型公牛与子代或种群中的关系信息）结合的情况下观察到最好的结果。总体而言，结果表明自回归模型下的 ssGBLUP 方法是一种可行且适用的方法，可用于葡萄牙荷斯坦牛纵向繁殖性状的基因组分析。在基因分型母牛与贡献公牛（基因分型公牛与子代或种群中的关系信息）结合的情况下观察到最好的结果。总体而言，结果表明自回归模型下的 ssGBLUP 方法是一种可行且适用的方法，可用于葡萄牙荷斯坦牛纵向繁殖性状的基因组分析。