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Association analysis for udder index and milking speed with imputed whole-genome sequence variants in Nordic Holstein cattle

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  • Julia Gazzoni Jardim, Laboratory of Reproduction and Animal Breeding, State University of North Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000 Parque California, Campos dos Goytacazes
  • ,
  • Bernt Guldbrandtsen
  • ,
  • Mogens Sandø Lund
  • Goutam Sahana

Genome-wide association testing facilitates the identification of genetic variants associated with complex traits. Mapping genes that promote genetic resistance to mastitis could reduce the cost of antibiotic use and enhance animal welfare and milk production by improving outcomes of breeding for udder health. Using imputed whole-genome sequence variants, we carried out association studies for 2 traits related to udder health, udder index, and milking speed in Nordic Holstein cattle. A total of 4,921 bulls genotyped with the BovineSNP50 BeadChip array were imputed to high-density genotypes (Illumina BovineHD BeadChip, Illumina, San Diego, CA) and, subsequently, to whole-genome sequence variants. An association analysis was carried out using a linear mixed model. Phenotypes used in the association analyses were deregressed breeding values. Multitrait meta-analysis was carried out for these 2 traits. We identified 10 and 8 chromosomes harboring markers that were significantly associated with udder index and milking speed, respectively. Strongest association signals were observed on chromosome 20 for udder index and chromosome 19 for milking speed. Multitrait meta-analysis identified 13 chromosomes harboring associated markers for the combination of udder index and milking speed. The associated region on chromosome 20 overlapped with earlier reported quantitative trait loci for similar traits in other cattle populations. Moreover, this region was located close to the FYB gene, which is involved in platelet activation and controls IL-2 expression; FYB is a strong candidate gene for udder health and worthy of further investigation.

Original languageEnglish
JournalJournal of Dairy Science
Pages (from-to)2199-2212
Number of pages14
Publication statusPublished - Mar 2018

    Research areas

  • genome-wide association study, milking speed, udder conformation

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