Individual wavenumbers of the infrared (IR) spectra of bovine milk have been shown to be moderately to highly heritable. The objective of this study was to identify genomic regions associated with individual milk IR wavenumbers. This is expected to provide information about the genetic background of milk composition and give insight in the relation between IR wavenumbers and milk components. For this purpose, a genome-wide association study was performed for a selected set of 50 individual IR wavenumbers measured on 1,748 Dutch Holstein cows. Significant associations were detected for 28 of the 50 wavenumbers. In total, 24 genomic regions distributed over 16 bovine chromosomes were identified. Major genomic regions associated with milk IR wavenumbers were identified on chromosomes 1, 5, 6, 14, 19, and 20. Most of these regions also showed significant associations with fat, protein, or lactose percentage. However, we also identified some new regions that were not associated with any one of these routinely collected milk composition traits. On chromosome 1, we identified 2 new genomic regions and hypothesized that they are related to variation in milk phosphorus content and orotic acid, respectively. On chromosome 20, we identified a new genomic region that seems to be related to citric acid. Identification of genomic regions associated with milk phosphorus content, orotic acid, and citric acid suggest that the milk IR spectra contain direct information on these milk components. Consequently milk IR analyses probably can be used to predict these milk components, which have low concentrations in milk; this can lead to novel applications of milk IR spectroscopy for dairy cattle breeding and herd management.

牛乳的红外（IR）光谱的单个波数已显示为中等至高度可遗传。这项研究的目的是确定与单个牛奶IR波数相关的基因组区域。预期这将提供有关牛奶成分遗传背景的信息，并提供有关IR波数与牛奶成分之间关系的见解。为此，对在1748头荷兰荷斯坦奶牛上测得的一组50个单独的IR波数进行了全基因组关联研究。在50个波数中，有28个被检测到显着关联。总共鉴定出分布在16个牛染色体上的24个基因组区域。在1号，5号，6号，14号，19号和20号染色体上鉴定了与牛奶IR波数相关的主要基因组区域。这些区域中的大多数也显示出与脂肪，蛋白质或乳糖百分比的显着关联。但是，我们还确定了一些与这些常规收集的牛奶成分特征中的任何一个都不相关的新区域。在1号染色体上，我们确定了2个新的基因组区域，并假设它们分别与乳中磷含量和乳清酸的变化有关。在20号染色体上，我们确定了一个新的基因组区域，该区域似乎与柠檬酸有关。与牛奶中磷含量，乳清酸和柠檬酸相关的基因组区域的鉴定表明，牛奶的红外光谱包含有关这些牛奶成分的直接信息。因此，牛奶IR分析可能可以用来预测这些牛奶成分，这些成分在牛奶中的浓度很低。