Sigdel Anil, Wu Xiao-Lin, Parker Gaddis Kristen L, Norman H Duane, Carrillo José A, Burchard Javier, Peñagaricano Francisco, Dürr João
Council on Dairy Cattle Breeding, Bowie, MD, United States.
Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, United States.
Front Genet. 2022 Apr 11;13:819678. doi: 10.3389/fgene.2022.819678. eCollection 2022.
Genetic selection has been an effective strategy to improve calving traits including stillbirth in dairy cattle. The primary objectives of the present study were to characterize stillbirth data and determine the feasibility of implementing routine genetic evaluations of stillbirth in five non-Holstein dairy breeds, namely Ayrshire, Guernsey, Milking Shorthorn, Brown Swiss, and Jersey. An updated sire-maternal grandsire threshold model was used to estimate genetic parameters and genetic values for stillbirth. Stillbirth data with the birth years of dams from 1995 to 2018 were extracted from the United States national calving ease database maintained by the Council on Dairy Cattle Breeding. The extracted stillbirth records varied drastically among the five dairy breeds. There were approximately 486K stillbirth records for Jersey and more than 80K stillbirth records for Brown Swiss. The direct and maternal heritability estimates of stillbirth were 6.0% (4.5-7.6%) and 4.7% (3.3-6.1%) in Jersey and 6.8% (3.2-10.5%) and 1.1% (0.6-2.9%) in Brown Swiss. The estimated genetic correlations between direct and maternal genetic effects for stillbirth were -0.15 (-0.38 to -0.08) in Jersey and -0.35 (-0.47 to -0.12) in Brown Swiss. The estimated genetic parameters for stillbirth in these two breeds were within close ranges of previous studies. The reliabilities of predicted transmitting abilities in Jersey and Brown Swiss increased substantially, thanks to the substantial increase in available stillbirth data in the past 10 years. The stillbirth records for Ayrshire, Guernsey, and Milking Shorthorn, which ranged approximately between 3K and 12K, are insufficient to implement reliable routine genetic evaluations of stillbirth in these three dairy breeds. Estimated genetic (co)variances and genetic values deviated considerably from the reported ranges of previous studies, and the reliabilities of predicted transmitting abilities were low in these three breeds. In conclusion, routine genetic evaluations of stillbirth are feasible in Brown Swiss and Jersey. However, reliable genetic evaluations of stillbirth in Ayrshire, Guernsey, and Milking Shorthorn require further data collection on stillbirth.
基因选择一直是改善奶牛产犊性状（包括死产）的有效策略。本研究的主要目的是描述死产数据，并确定在五个非荷斯坦奶牛品种（即艾尔夏牛、根西牛、乳用短角牛、瑞士褐牛和泽西牛）中实施死产常规遗传评估的可行性。使用更新的父系-母系祖父阈值模型来估计死产的遗传参数和遗传值。从美国奶牛育种委员会维护的国家产犊难易数据库中提取了1995年至2018年母畜出生年份的死产数据。在这五个奶牛品种中，提取的死产记录差异很大。泽西牛有大约48.6万条死产记录，瑞士褐牛有超过8万条死产记录。泽西牛死产的直接遗传力估计值为6.0%（4.5-7.6%），母系遗传力估计值为4.7%（3.3-6.1%）；瑞士褐牛死产的直接遗传力估计值为6.8%（3.2-10.5%），母系遗传力估计值为1.1%（0.6-2.9%）。泽西牛死产的直接和母系遗传效应之间的估计遗传相关为-0.15（-0.38至-0.08），瑞士褐牛为-0.35（-0.47至-0.12）。这两个品种死产估计的遗传参数与先前研究的范围接近。由于过去10年可用死产数据的大幅增加，泽西牛和瑞士褐牛预测传递能力的可靠性大幅提高。艾尔夏牛、根西牛和乳用短角牛的死产记录约在3000至12000条之间，不足以在这三个奶牛品种中实施可靠的死产常规遗传评估。估计的遗传（协）方差和遗传值与先前研究报告的范围有很大偏差，这三个品种预测传递能力的可靠性较低。总之，瑞士褐牛和泽西牛进行死产常规遗传评估是可行的。然而，要对艾尔夏牛、根西牛和乳用短角牛进行可靠的死产遗传评估，还需要进一步收集死产数据。
