title: Quantitative trait loci for clinical mastitis on chromosomes 2, 6, 14 and 20 in Norwegian Red cattle.
abstract: Mastitis is the most frequent and costly disease in dairy production and solutions leading to a reduction in the incidence of mastitis are highly demanded. Here a genome-wide association study was performed to identify polymorphisms affecting susceptibility to mastitis. Genotypes for 17 349 SNPs distributed across the 29 bovine autosomal chromosomes from a total of 2589 sires with 1 389 776 daughters with records on clinical mastitis were included in the analysis. Records of occurrence of clinical mastitis were divided into seven time periods in the first three lactations in order to identify quantitative trait loci affecting mastitis susceptibility in particular phases of lactation. The most convincing results from the association mapping were followed up and validated by a combined linkage disequilibrium and linkage analysis. The study revealed quantitative trait loci affecting occurrence of clinical mastitis in the periparturient period on chromosomes 2, 6 and 20 and a quantitative trait locus affecting occurrence of clinical mastitis in late lactation on chromosome 14. None of the quantitative trait loci for clinical mastitis detected in the study seemed to affect lactation average of somatic cell score. The SNPs highly associated with clinical mastitis lie near both the gene encoding interleukin 8 on chromosome 6 and the genes encoding the two interleukin 8 receptors on chromosome 2.
authors: Department of Animal and Aquacultural Sciences, Centre for Integrative Genetics, Norwegian University of Life Sciences, N-1432 Aas, Norway. marte.sodeland@umb.no
authors: M
authors: M
authors: Sodeland
authors: M P
authors: MP
authors: Kent
authors: H G
authors: HG
authors: Olsen
authors: M A
authors: MA
authors: Opsal
authors: M
authors: M
authors: Svendsen
authors: E
authors: E
authors: Sehested
authors: B J
authors: BJ
authors: Hayes
authors: S
authors: S
authors: Lien
mesh_terms: D000818:Animals; D002417:Cattle; D033481:Chromosomes, Mammalian; D005260:Female; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D015810:Linkage Disequilibrium; D008297:Male; D008414:Mastitis, Bovine / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci