Enhancing resistance to ketosis through genomics

高产奶牛易患酮症，这是一种代谢性疾病，会对奶牛的健康、生育力和产量产生负面影响。酮症抗性作为一种健康性状，由于其多基因性、表型模糊以及与产奶量的遗传相关性不佳，难以进行遗传改良。该项目旨在澄清围绕这一特性的一些不确定性，并通过基因组学改善酮症抗性。数千头奶牛将使用一种新的低密度芯片进行基因分型，该芯片包含在酮症候选基因中鉴定的标记。将被基因分型的动物已经有50K基因型，这将允许为任何已经用50K阵列进行基因分型的动物植入新的snp。对成千上万动物的基因型进行归因将极大地提高检测与酮症表型相关的能力。将对生产者记录的临床酮症和移位性皱胃病例进行关联分析，测量牛奶β -羟基丁酸，以及对这些性状的去压力估计育种值。这些结果将在一个独立的人群中得到验证，并通过对最有效的snp进行功能研究。这项工作将提高我们对酮症的理解，为通过选择增强抗性提供基因组工具，并为确定为酮症易感奶牛提供有针对性的预防和治疗策略。

High-yielding dairy cattle are susceptible to ketosis, a metabolic disease, which negatively affects the health, fertility and production of the cow. As a health trait, ketosis-resistance is difficult to improve genetically due to its polygenic nature, fuzzy phenotypes and unfavorable genetic correlation to milk production. The proposed project aims to clarify some of the uncertainty surrounding this trait and improve ketosis-resistance through genomics. Several thousand cows will be genotyped with a new, low-density chip, which contains markers that were identified in candidate genes for ketosis. The animals that will be genotyped already have 50K genotypes, which will allow for imputation of the new SNPs for any animal that has been genotyped with the 50K array. Imputing the genotypes of hundreds of thousands of animals will greatly improve the power to detect associations with ketosis phenotypes. Association analyses will be conducted for producer-recorded cases of clinical ketosis and displaced abomasum, measured milk beta-hydroxybutyrate, as well as deregressed estimated breeding values for each of these traits. These results will be validated in an independent population, as well by conducting functional studies of the most effective SNPs. This work will improve our understanding of ketosis, provide genomic tools to enhance resistance through selection and lead to targeted prevention and treatment strategies for cows identified as being susceptible to ketosis.