Department of Animal Sciences, University of Florida, Gainesville 32611.
Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada.
J Dairy Sci. 2019 Nov;102(11):10020-10029. doi: 10.3168/jds.2019-17068. Epub 2019 Aug 30.
Elongation of the preimplantation conceptus is a requirement for pregnancy success in ruminants, and failures in this process are highly associated with subfertility in dairy cattle. Identifying genetic markers that are related to early conceptus development and survival and utilizing these markers in selective breeding can improve the reproductive efficiency of dairy herds. Here, we evaluated the association of 1,679 SNP markers within or close to 183 candidate genes involved in lipid metabolism of the elongating conceptus with different fertility traits in US Holstein cattle. A total of 27,371 bulls with predicted transmitting ability records for daughter pregnancy rate, cow conception rate, and heifer conception rate were used as the discovery population. The associations found in the discovery population were validated using 2 female populations (1,122 heifers and 2,138 lactating cows) each with 4 fertility traits, including success to first insemination, number of services per conception, age at first conception for heifers, or days open for cows. Marker effects were estimated using a linear mixed model with SNP genotype as a linear covariate and a random polygenic effect. After multiple testing correction, 39 SNP flagging 27 candidate genes were associated with at least one fertility trait in the discovery population. Of these 39 markers, 3 SNP were validated in the heifer population and 4 SNP were validated in the cow population. The 3 SNP validated in heifers are located within or near genes CAT, MYOF, and RBP4, and the 4 SNP validated in lactating cows are located within or close to genes CHKA, GNAI1, and HMOX2. These validated genes seem to be relevant for reducing pregnancy losses, and the SNP within these genes are excellent candidates for inclusion in genomic tests to improve reproductive performance in dairy cattle.
胚胎前延长是反刍动物妊娠成功的要求，而这一过程的失败与奶牛的低生育率高度相关。鉴定与早期胚胎发育和生存相关的遗传标记，并在选择性繁殖中利用这些标记，可以提高奶牛群的繁殖效率。在这里，我们评估了与伸长胚胎中脂质代谢相关的 183 个候选基因内或附近的 1679 个 SNP 标记与美国荷斯坦奶牛不同生育力性状的关联。共有 27371 头公牛具有预测的母系妊娠率、牛受孕率和小母牛受孕率的传递能力记录，作为发现群体。在发现群体中发现的关联使用 2 个雌性群体（1122 头小母牛和 2138 头泌乳牛）进行了验证，每个群体都有 4 个生育力性状，包括首次配种成功率、每配种服务次数、小母牛首次受孕年龄或奶牛开放天数。使用线性混合模型，将 SNP 基因型作为线性协变量和随机多基因效应进行标记效应估计。在多重测试校正后，有 39 个 SNP 标记了 27 个候选基因，与发现群体中的至少一个生育力性状相关。在这 39 个标记中，有 3 个 SNP 在小母牛群体中得到了验证，4 个 SNP 在奶牛群体中得到了验证。在小母牛中验证的 3 个 SNP 位于基因 CAT、MYOF 和 RBP4 内或附近，在泌乳牛中验证的 4 个 SNP 位于基因 CHKA、GNAI1 和 HMOX2 内或附近。这些验证的基因似乎与减少妊娠损失有关，这些基因内的 SNP 是提高奶牛繁殖性能的基因组测试中极好的候选基因。
