Milk urea nitrogen phenotypes and genome-wide association summary statistics for a multi-breed Romanian dual-purpose cattle population

Corrected per-animal milk urea nitrogen (MUN) phenotypes for 406 lactating cows from two Romanian farms, and the full genome-wide association summary statistics for the corresponding scan. Phenotypes are released at two levels: the record-level data after quality control, with the variables of the adjustment model (lactation stage, season, year, parity, days in milk, breed and farm), and the per-animal adjusted mean that the association analysis used. The cohort comprises 324 Romanian Simmental, 57 Romanian Brown Swiss and 25 Holstein cows, contributing 13,722 test-day records. The phenotype is the fixed-effects-only marginal adjusted mean of MUN in mg/dL, obtained from a linear mixed model on lactation stage, season, year and parity with animal as a random effect. Summary statistics come from a mixed linear model association analysis with leave-one-chromosome-out (GCTA MLMA-LOCO), fitting a binary farm indicator and the first four principal components as fixed covariates, with breed carried by the genomic relationship matrix.</p><p>Animals are identified by anonymised identifiers that match those used in the corresponding genotype deposit in the European Variation Archive. The key linking these identifiers to national herd-book identifiers is retained by the authors and is not released. These data accompany the article submitted to Frontiers in Animal Science (manuscript 1937481)