Submitted to: Frontiers in Livestock Genomics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/31/2011
Publication Date: 11/22/2011
Citation: Zanella, R., Casas, E., Snowder, G., Neibergs, H. L. 2011. Fine mapping of loci on BTA2 and BTA26 associated with bovine viral diarrhea persistent infection and linked with bovine respiratory disease in cattle. Frontiers in Genetics. 2:82. Available: http://www.frontiersin.org/livestock_genomics/10.3389/fgene.2011.00082/abstract. Interpretive Summary: Diseases are an important factor affecting productivity of the beef industry. As an extension of a larger study to detect the location of genes associated with economically important traits in cattle, the objective of the present study was to refine the location of genes influencing incidence of diseases in cattle on bovine chromosomes 2 and 26. Two populations were used in this study. The first population was used to identify regions on bovine chromosomes 2 and 26 harboring genes associated with bovine respiratory disease (pneumonia). The second population was used to ascertain if similar genes were associated with persistent infection of bovine viral diarrhea. Results from this study narrowed the location of the genes to 11 genomic regions (loci) on chromosome 2 and to 8 genomic regions on chromosome 26. This study shows that some loci on these chromosomes are jointly involved in the maternal and fetal immunological response against persistent infection of bovine viral diarrhea, and some loci are involved in solely maternal or fetal susceptibility to the disease. Although bovine viral diarrhea virus is one of the leading pathogens associated with pneumonia, the loci linked with pneumonia were not shared with those associated with persistent infection of bovine viral diarrhea. Further studies will be needed to identify the causative mutations responsible for susceptibility to pneumonia and persistent infection of bovine viral diarrhea on chromosomes 2 and 26.
Technical Abstract: Bovine respiratory disease (BRD) is considered to be the most costly infectious disease in the cattle industry. Bovine viral diarrhea virus (BVDV) is one of the pathogens involved with the BRD complex of disease. Bovine viral diarrhea virus infection also negatively impacts cow reproduction and calf performance. Loci associated with persistently infected animals (BVD-PI) and linked with BRD have previously been identified near 14 Mb on bovine chromosome 2 (BTA2) and 15.3 Mb on bovine chromosome 26 (BTA26). The objective of this study was to refine the loci associated with BVD persistent infection and linked with BRD. Association testing for BVD-PI was performed on a population of 65 BVD-PI calves, 51 of their dams, and 60 unaffected calves (controls) from the same herd that were genotyped with 175 single nucleotide polymorphisms (SNPs) on BTA2 and 209 SNPs on BTA26. Comparisons were made between BVD-PI calves and control calves and the dams of BVD-PI calves and control calves. For the linkage analysis of BRD, the same markers were used to genotype 2 half-sib families consisting of the sires and 72 BRD positive animals and 148 BRD negative animals. Refining of the regions on BTA2 and BTA26 associated with BVD-PI and linked with BRD infection was achieved. Using an allelic chi-square test, 11 loci on BTA2 and 8 loci on BTA26 were associated with the dams of the BVD-PI calves (P < 0.05). Associations (P < 0.05) with BVD-PI calves were identified with 5 loci on BTA2 and 10 loci on BTA26. One locus on BTA2 and two loci on BTA26 were found to be linked (P < 0.05) with BRD.