title: Beta-2-microglobulin haplotypes in U.S. beef cattle and association with failure of passive transfer in newborn calves.
abstract: Failure of passive transfer (FPT) is a condition in which neonates do not acquire protective serum levels of maternal antibodies. A principal component of antibody transport is the neonatal receptor for the Fc portion of immunoglobulin, a heterodimer of a MHC-1 alpha-chain homolog ( FCGRT) and beta-2-microglobulin ( B2M). Previously, two FCGRT haplotypes were associated with differences in immunoglobulin G (IgG) passive transfer in cattle (Laegreid et al. (2002) Mamm Genome 13, 704-710). The present study had two objectives: first, to characterize the B2M haplotype structure in a diverse group of U.S. beef cattle, and second, to evaluate those haplotypes for association with either high or low serum IgG levels in newborn calves. Twelve single nucleotide polymorphisms (SNPs), assorted into eight haplotypes, were identified by sequencing regions of B2M exons II and IV in a multi-breed panel of 96 beef cattle. Calves homozygous for one of the eight haplotypes ( B2M 2,2) were at increased risk of FPT (odds ratio = 10.60, CI(95%) 2.07-54.24, p = 0.005). These results indicate that this haplotype is in linkage disequilibrium with genetic risk factors affecting passive transfer of IgG in beef calves, an important determinant of neonatal calf morbidity and mortality.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center (MARC), Spur 18D, P.O. Box 166, Clay Center, Nebraska 68933, USA. clawson@email.marc.usda.gov
authors.forename: Michael L
authors.initials: ML
authors.lastname: Clawson
authors.forename: Michael P
authors.initials: MP
authors.lastname: Heaton
authors.forename: Carol G
authors.initials: CG
authors.lastname: Chitko-McKown
authors.forename: James M
authors.initials: JM
authors.lastname: Fox
authors.forename: Timothy P L
authors.initials: TP
authors.lastname: Smith
authors.forename: Warren M
authors.initials: WM
authors.lastname: Snelling
authors.forename: John W
authors.initials: JW
authors.lastname: Keele
authors.forename: William W
authors.initials: WW
authors.lastname: Laegreid
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D001483:Base Sequence; D002417:Cattle / Q000235:genetics*; D002874:Chromosome Mapping; D017931:DNA Primers; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes / Q000235:genetics*; D015395:Histocompatibility Antigens Class I; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood*; D015810:Linkage Disequilibrium; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D011961:Receptors, Fc / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014481:United States; D001613:beta 2-Microglobulin / Q000235:genetics*
chemical_list: D017931:DNA Primers; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D011961:Receptors, Fc; D001613:beta 2-Microglobulin; C100688:Fc receptor, neonatal