|Heaton, Michael - Mike|
|Chitko Mckown, Carol|
|Smith, Timothy - Tim|
Submitted to: Mammalian Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2002
Publication Date: 12/1/2002
Citation: LAEGREID, W.W., HEATON, M.P., KEEN, J.E., GROSSE, W.M., CHITKO MCKOWN, C.G., SMITH, T.P., KEELE, J.W., BENNETT, G.L., BESSER, T.E. ASSOCIATION OF BOVINE NEONATAL FC RECEPTOR GENE ALPHA-CHAIN GENE (FCGRT) HAPLOTYPES WITH SERUM IgG CONCENTRATION IN NEWBORN CALVES. MAMMALIAN GENOME. 2002. v. 13. p. 704-710. Interpretive Summary: Calves are born without any antibodies. They obtain antibodies from their mothers' milk in the first 24 hours of life. If for any reason they do not get enough antibodies, they are highly prone to illness and death from infectious diseases. This study examined the effect of genetic variation on antibody concentration in day old calves. The nucleotide sequence of a gene that encodes a protein thought to be involved in uptake of antibody from the intestinal tract of young animals was determined in populations of cattle. Specific nucleotide sequence changes in this gene were associated with low or high concentrations of antibody in calves. These results indicate a genetic component to the problem of low antibody levels in young calves and may lead to strategies to control this important problem.
Technical Abstract: Calves are born with little or no circulating immunoglobulin. Within 24 hours after birth, calves acquire immunoglobulins through passive transfer from ingestion of maternal colostrum. When this process fails, calves are at high risk for postnatal infections. Uptake of IgG from the intestinal lumen and regulation of IgG levels in mammary secretions are mediated by FcRn, a heteroduplex, IgG-specific receptor expressed on epithelial cells. To test the hypothesis that allelic variation in FCGRT (which encodes the alpha-chain of FcRn) is associated with variation of IgG concentration in neonatal calves, five SNPs were identified by sequencing 1,305 bp of FCGRT genomic DNA from a multi-breed panel of 96 cattle and 27 founders of a reference population. Five SNP haplotypes were defined, verified by segregation and used to test association of FCGRT with neonatal IgG concentration in a case-control study. The results of this study demonstrated that dams with FCGRT haplotype 3 had a significantly greater risk of failure of passive transfer in their calves (odds ratio [OR] = 3.80, CI95% 1.10 - 13.18, p = 0.035). Calves with FCGRT haplotype 2 were less likely to have high levels of passively acquired immunoglobulin (OR = 0.18, CI95% 0.05 - 0.68, p = 0.011). These results indicate that the bovine FCGRT haplotype markers are in linkage disequilibrium with genetic risk factors affecting passive transfer of IgG in beef cattle.