The BovMAS Consortium: identification of QTL for milk yield and milk protein percent on chromosome 14 in the Brown Swiss breed

Abstract

Numerous studies have found a large number of QTL associated with productive and functional traits in the cattle genome. Several Countries have already established research programs aiming at identification and exploitation of QTLs in dairy cattle (Bovenhuis and Schrooten 2002). However, the published results are not directly exploitable for MAS, as commercial interests limit the information in the literature, and because marker-QTL phase is specific to each family

DGAT1p.K232A polymorphism in dairy and dual purpose Italian cattle breeds

“…In Italian Brown, Bagnato et al (2008) reported the presence of QTL for milk yield and protein percent- age in the DGAT1 region of BTA14, but all sires were homozygous p.232AA (Bagnato et al 2005), as expected by the allele frequencies reported here. This could suggest that other mutations in this locus or in other close genes should be involved in the observed effects, confirming what was reported by Fontanesi et al (2005) in the Italian Holstein population.…”

Combining evidence of selection with association analysis increases power to detect regions influencing complex traits in dairy cattle

“…However, there is growing evidence for additional polymorphisms in the DGAT1 gene and its neighborhood that cause phenotypic variation for milk production traits eg [ 52 , 53 ]. Of particular interest is a QTL mapping study in the German-Austrian-Italian BS population [ 54 ], that reported significant QTL for milk yield and protein percent in the DGAT1 region although all bulls in this study were shown to be homozyogous for the p.K232A polymorphism [ 55 ]. This finding is supported by the large SNP effects estimated for fat and protein percent in the US - BS population ( http://aipl.arsusda.gov/Report_Data/Marker_Effects/marker_effects.cfm?Breed=BS ) albeit the near fixation of allele A in this breed.…”