Original ResearchPublished 30 September 2026Repeatability and genetic architecture of milk urea nitrogen in a multi-breed Romanian dual-purpose cattle population: a genome-wide association study and the impact of phenotype definitionDaniel George Bratu · Şerban Blaga-Voicu · Bianca Zanfira · Călin Mircu · Ioana Irina Spătaru · Iuliu Torda · Vlad Mihai Cocioba · Alexandru Eugeniu Mizeranschi · Daniela Elena Ilie · Ludovic Toma Cziszter · Dorin Alexandru Vizitiu · Oana Maria Boldura · Ioan HuţuFrontiers in Animal Sciencedoi 10.3389/fanim.2026.1937481