|Heaton, Michael - Mike|
|Chitko Mckown, Carol|
|Smith, Timothy - Tim|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/6/2001
Publication Date: N/A
Technical Abstract: Passive transfer of antibodies from maternal colostrum into the circulation of neonatal calves contributes significantly to protection against postnatal infections. In rodents, IgG1 levels in the mammary gland are thought to be regulated by an IgG1-specific receptor expressed on acinar epithelial cells, designated FcRn. The bovine version of this receptor has been shown to be expressed in bovine mammary gland but its involvement in transfer of IgG into mammary secretions has yet to be confirmed. To determine whether genetic variation in bovine FCRN might be associated with differences in passive transfer of IgG, cDNA and partial genomic sequences for bFCRN were determined. Five single nucleotide polymorphism (SNP) markers were identified by sequencing two PCR amplicons across a panel of 96 North American beef cattle. Polymorphisms were verified by segregation in a reference population and with genotyping assays utilizing matrix- assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS). Five haplotypes were identified and their frequencies estimated in North American beef cattle. A case-control study in beef calves demonstrated an association between bFCRN haplotype 2 in dams and failure of passive transfer in their calves (OR = 2.83, CI95% 1.08-7.43, p = 0.03). Haplotype 3 was negatively associated with high levels of passively acquired immunoglobulin in neonatal calves (OR = 0.27, CI95% 0.08-0.87, p = 0.03). These results indicate that the genomic region where the bFCRN locus resides contains loci that affect passive transfer in beef cattle. Further testing is required to estimate the predictive value of these markers in commercial populations of beef cattle.