title: Associations of the bovine major histocompatibility complex DRB3 (BoLA-DRB3) with production traits in Canadian dairy cattle.
abstract: Associations of two alleles of the bovine major histocompatibility complex DRB3 gene (BoLA-DRB3) with lowered somatic cell score (SCS) and occurrence of disease (BoLA-DRB3.2* 16 and *23, respectively) have previously been documented. The objective of this study was to evaluate potential relationships between BoLA-DRB3 alleles with production traits, namely 305-day milk, milk fat and milk protein yield, in a population of Canadian dairy cattle (Holstein, n = 835 and Jersey, n = 66) over the course of two lactations. No significant associations were detected between BoLA alleles and production traits in Jerseys. In Holsteins, alleles *16 and *23 also did not show associations with production traits but allele *8 was significantly associated with increased 305-day milk, fat and protein yields in the previous lactation (the lactation prior to immunization with a gram negative core antigen vaccine), and with increased protein production in the subsequent (with reference to the time of immunization) lactation. Allele *22 was associated with decreased milk and protein yield in both previous and subsequent lactations. Therefore, it can be concluded that increasing or decreasing the frequency of BoLA alleles *16 and *23 to reduce SCS or increase resistance to mastitis in this population would not have adverse effects on production in this population, and that certain BoLA alleles (*8 and *22) are associated with altered production traits in Canadian Holsteins.
authors.affiliation: Department of Pathobiology, University of Guelph, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Sharif
authors.forename: B A
authors.initials: BA
authors.lastname: Mallard
authors.forename: B N
authors.initials: BN
authors.lastname: Wilkie
authors.forename: J M
authors.initials: JM
authors.lastname: Sargeant
authors.forename: H M
authors.initials: HM
authors.lastname: Scott
authors.forename: J C
authors.initials: JC
authors.lastname: Dekkers
authors.forename: K E
authors.initials: KE
authors.lastname: Leslie
mesh_terms: D000483:Alleles; D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D005260:Female; D005802:Genes, MHC Class II / Q000235:genetics*; D007113:Immunity, Innate / Q000235:genetics; D007774:Lactation / Q000235:genetics*; D008055:Lipids / Q000096:biosynthesis / Q000235:genetics; D008414:Mastitis, Bovine / Q000276:immunology; D008892:Milk / Q000378:metabolism; D008894:Milk Proteins / Q000096:biosynthesis / Q000235:genetics; D009864:Ontario; D019655:Quantitative Trait, Heritable
chemical_list: D008055:Lipids; D008894:Milk Proteins