Milk production phenotypes are the main focus of genetic selection in dairy herds, and although there are many genes identified as related to the biology of these traits in pure breeds, little is known about crossbreed animals. This study aimed to identify potential genes associated with the 305-day milk yield in 337 crossbreed Gir × Holstein (Girolando) animals. Milk production records were genotyped for 45,613 single-nucleotide polymorphisms (SNPs). This dataset was used for a genome-wide association study (GWAS) using the 305-day milk yield adjusted for the fixed effects of herd and year and linear and quadratic effects of age at calving (in days) and calving factor averaged per animal. Genes within the significant SNPs were retrieved from the Bos taurus ARS-UCD1.2 assembly (bosTau9) for gene ontology analysis. In summary, the GWAS identified 52 SNPs associated [p ≤ 10^–4, false discovery rate (FDR) = 8.77%] with milk production, including NUB1 and SLC24A2, which were previously described as related to milk production traits in cattle. The results suggest that SNPs associated mainly with NUB1 and SLC24A2 could be useful to understand milk production in Girolando and used as predictive markers for selecting genetic predisposition for milk yield in Girolando.

奶产量表型是奶牛群体遗传选择的主要重点，尽管在纯种中有许多与这些性状的生物学相关的基因，但对杂交动物知之甚少。这项研究旨在鉴定与337头杂交Gir×Holstein（Girolando）动物的305天产奶量相关的潜在基因。对牛奶生产记录进行了45,613个单核苷酸多态性（SNP）的基因分型。该数据集用于全基因组关联研究（GWAS），其中使用了305天的产奶量，根据产犊和年份的固定影响以及产犊（以天为单位）和每个动物平均产犊因子的年龄的线性和二次影响进行了调整。从SNP中检索出重要SNP内的基因。金牛座用于基因本体分析的ARS-UCD1.2组件（bosTau9）。总之，GWAS确定了52个与[p≤10 ^–4时，牛奶产量（包括NUB1和SLC24A2）的错误发现率（FDR）= 8.77％]，这先前被描述为与牛的牛奶产量性状有关。结果表明，主要与NUB1和SLC24A2相关的SNP可能有助于了解Girolando的产奶量，并可用作选择Girolando产奶遗传易感性的预测标记。