title: Genome-wide scan to detect quantitative trait loci for milk urea nitrogen in Dutch Holstein-Friesian cows.
abstract: Studies have reported genetic variation in milk urea nitrogen (MUN) between cows, suggesting genetic differences in nitrogen efficiency between cows. In this paper, the results of a genome-wide scan to identify quantitative trait loci (QTL) that contribute to genetic variation in MUN and MUN yield are presented. Two to 3 morning milk samples were taken from 1,926 cows, resulting in 5,502 test-day records. Test-day records were corrected for systematic environmental effects using a repeatability animal model. Averages of corrected phenotypes of 849 cows, belonging to 7 sire families, were used in an across-family multimarker regression approach to detect QTL. Animals were successfully genotyped for 1,341 single nucleotide polymorphisms. The QTL analysis resulted in 4 chromosomal regions with suggestive QTL: Bos taurus autosomes (BTA) 1, 6, 21, and 23. On BTA 1, 2 suggestive QTL affecting MUN were detected at 60 and 140 cM. On BTA 6, 1 suggestive QTL affecting both MUN and MUN yield was detected at 103 cM. On BTA 21, 1 suggestive QTL affecting MUN yield was detected at 83 cM. On BTA 23, 1 suggestive QTL affecting MUN was detected at 54 cM. Quantitative trait loci for MUN and MUN yield were suggestive and each explained between 2 and 3% of the phenotypic variance.
authors.affiliation: Animal Breeding and Genomics Centre, Wageningen University, PO Box 338, 6700 AH Wageningen, the Netherlands. Aniek.Bouwman@wur.nl
authors.forename: A C
authors.initials: AC
authors.lastname: Bouwman
authors.forename: G C B
authors.initials: GC
authors.lastname: Schopen
authors.forename: H
authors.initials: H
authors.lastname: Bovenhuis
authors.forename: M H P W
authors.initials: MH
authors.lastname: Visker
authors.forename: J A M
authors.initials: JA
authors.lastname: van Arendonk
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics*; D005260:Female; D055106:Genome-Wide Association Study; D008297:Male; D008892:Milk / Q000737:chemistry*; D009426:Netherlands; D009584:Nitrogen / Q000032:analysis*; D040641:Quantitative Trait Loci / Q000235:genetics*; D014508:Urea / Q000032:analysis
chemical_list: D014508:Urea; D009584:Nitrogen