Dataset Information

Association of toll-like receptors 2 and 6 polymorphism with clinical mastitis and production traits in Holstein cattle.

ABSTRACT: Mastitis is a costly disease of dairy cattle as it causes a loss in milk yield and milk quality in affected cows. Toll-like receptor (TLR) genes play a role in the host response to a variety of organisms including those inducing mastitis. In the present study, we investigated the polymorphism of TLR2, 4, 6 and 9 genes in Holstein cattle and their possible association with clinical mastitis (CM), milk somatic cell scores (SCS) and milk production traits. From a large commercial Holstein herd, thirty-eight blood samples were collected; 19 from cows without a previous lifetime history of mastitis (non-susceptible), and 19 from Holstein cows with at least three previous episodes of mastitis (susceptible). Genotyping of the four TLRs was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLPs) with Rsa1, MSP1, Hha1, HaeIII, and Taq1 enzymes guided with DNA sequencing. Seven novel non-synonymous single-nucleotide polymorphisms (SNPs) were identified among TLR2, 4, and 6 in susceptible animals. Association was found in Taq1-TLR2 gene polymorphism with CM, fat percentage and peak yield (PY). The association of Taq1-TLR6 and PY and lactation persistency was also shown. Mutations in TLRs that were repeatedly reported in susceptible cows provide potential genetic marker assisted selection (MAS) for mastitis resistance in dairy cattle.

SUBMITTER: Elmaghraby MM

PROVIDER: S-EPMC6184031 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Association of toll-like receptors 2 and 6 polymorphism with clinical mastitis and production traits in Holstein cattle.

Elmaghraby M M MM El-Nahas A F AF Fathala M M MM Sahwan F M FM Tag El-Dien M A MA

Iranian journal of veterinary research 20180101 3

Mastitis is a costly disease of dairy cattle as it causes a loss in milk yield and milk quality in affected cows. Toll-like receptor (TLR) genes play a role in the host response to a variety of organisms including those inducing mastitis. In the present study, we investigated the polymorphism of TLR2, 4, 6 and 9 genes in Holstein cattle and their possible association with clinical mastitis (CM), milk somatic cell scores (SCS) and milk production traits. ...[more]

PMID: 30349567

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Project description:BackgroundProduction and health traits are central in cattle breeding. Advances in next-generation sequencing technologies and genotype imputation have increased the resolution of gene mapping based on genome-wide association studies (GWAS). Thus, numerous candidate genes that affect milk yield, milk composition, and mastitis resistance in dairy cattle are reported in the literature. Effect-bearing variants often affect multiple traits. Because the detection of overlapping quantitative trait loci (QTL) regions from single-trait GWAS is too inaccurate and subjective, multi-trait analysis is a better approach to detect pleiotropic effects of variants in candidate genes. However, large sample sizes are required to achieve sufficient power. Multi-trait meta-analysis is one approach to deal with this problem. Thus, we performed two multi-trait meta-analyses, one for three milk production traits (milk yield, protein yield and fat yield), and one for milk yield and mastitis resistance.ResultsFor highly correlated traits, the power to detect pleiotropy was increased by multi-trait meta-analysis compared with the subjective assessment of overlapping of single-trait QTL confidence intervals. Pleiotropic effects of lead single nucleotide polymorphisms (SNPs) that were detected from the multi-trait meta-analysis were confirmed by bivariate association analysis. The previously reported pleiotropic effects of variants within the DGAT1 and MGST1 genes on three milk production traits, and pleiotropic effects of variants in GHR on milk yield and fat yield were confirmed. Furthermore, our results suggested that variants in KCTD16, KCNK18 and ENSBTAG00000023629 had pleiotropic effects on milk production traits. For milk yield and mastitis resistance, we identified possible pleiotropic effects of variants in two genes, GC and DGAT1.ConclusionsMulti-trait meta-analysis improves our ability to detect pleiotropic interactions between milk production traits and identifies variants with pleiotropic effects on milk production traits and mastitis resistance. In particular, this should contribute to better understand the biological mechanisms that underlie the unfavorable genetic correlation between milk yield and mastitis.

Project description:BACKGROUND: Breeding for enhanced immune response (IR) has been suggested as a tool to improve inherent animal health. Dairy cows with superior antibody-mediated (AMIR) and cell-mediated immune responses (CMIR) have been demonstrated to have a lower occurrence of many diseases including mastitis. Adaptive immune response traits are heritable, and it is, therefore, possible to breed for improved IR, decreasing the occurrence of disease. The objective of this study was to perform genome-wide association studies to determine differences in genetic profiles among Holstein cows classified as High or Low for AMIR and CMIR. From a total of 680 cows with immune response phenotypes, 163 cows for AMIR (81 High and 82 Low) and 140 for CMIR (75 High and 65 Low) were selectively genotyped using the Illumina Bovine SNP50 BeadChip. Results were validated using an unrelated population of 164 Holstein bulls IR phenotyped for AMIR and 146 for CMIR. RESULTS: A generalized quasi likelihood score method was used to determine single nucleotide polymorphisms (SNP) and chromosomal regions associated with immune response. After applying a 5% chromosomal false discovery rate, 186 SNPs were significantly associated with AMIR. The majority (93%) of significant markers were on chromosome 23, with a similar peak found in the bull population. For CMIR, 21 SNP markers remained significant. Candidate genes within 250,000 base pairs of significant SNPs were identified to determine biological pathways associated with AMIR and CMIR. Various pathways were identified, including the antigen processing and presentation pathway, important in host defense. Candidate genes included those within the bovine Major Histocompatability Complex such as BoLA-DQ, BoLA-DR and the non-classical BoLA-NC1 for AMIR and BoLA-DQ for CMIR, the complement system including C2 and C4 for AMIR and C1q for CMIR, and cytokines including IL-17A, IL17F for AMIR and IL-17RA for CMIR and tumor necrosis factor for both AMIR and CMIR. Additional genes associated with CMIR included galectins 1, 2 and 3, BCL2 and ?-defensin. CONCLUSIONS: The significant genetic variation associated with AMIR and CMIR in this study may imply feasibility to include immune response in genomic breeding indices as an approach to improve inherent animal health.

Project description:Simple Summary Udder conformation traits are economically important for dairy animals in the dairy industry. Milk production loss can be reduced via a better udder structure in dairy cattle. Udder traits are related to milk production and the somatic cell count, which is a sign of mammary infections (mastitis); as such, it is vital to understand the genetic architecture underlying udder traits in Holstein Friesian cattle for genetic development and long-term selection. Through a GWAS on udder structure traits in Chinese Holstein cattle, we identified several significant single-nucleotide polymorphisms (SNPs) and candidate genes associated with udder traits. The results could provide useful information regarding the genetics architecture of udder structure traits, thus improving the genetic information, health, longevity, and production of dairy cattle. Abstract Udder conformation traits are one of the most economic traits in dairy cows, greatly affecting animal health, milk production, and producer profitability in the dairy industry. Genetic analysis of udder structure and scores have been developed in Holstein cattle. In our research, we conducted a genome-wide association study for five udder traits, including anterior udder attachment (AUA), central suspensory ligament (CSL), posterior udder attachment height (PUAH), posterior udder attachment width (PUAW), and udder depth (UD), in which the fixed and random model circulating probability unification (FarmCPU) model was applied for the association analysis. The heritability and the standard errors of these five udder traits ranged from 0.04 ± 0.00 to 0.49 ± 0.03. Phenotype data were measured from 1000 Holstein cows, and the GeneSeek Genomic Profiler (GGP) Bovine 100 K SNP chip was used to analyze genotypic data in Holstein cattle. For GWAS analysis, 984 individual cows and 84,407 single-nucleotide polymorphisms (SNPs) remained after quality control; a total of 18 SNPs were found at the GW significant threshold (p < 5.90 × 10−7). Many candidate genes were identified within 200kb upstream or downstream of the significant SNPs, which include MGST1, MGST2, MTUS1, PRKN, STXBP6, GRID2, E2F8, CDH11, FOXP1, SLF1, TMEM117, SBF2, GC, ADGRB3, and GCLC. Pathway analysis revealed that 58 Gene Ontology (GO) terms and 18 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched with adjusted p values, and these GO terms and the KEGG pathway analysis were associated with biological information, metabolism, hormonal growth, and development processes. These results could give valuable biological information for the genetic architecture of udder conformation traits in dairy Holstein cattle.

Dataset Information

Association of toll-like receptors 2 and 6 polymorphism with clinical mastitis and production traits in Holstein cattle.

Publications

Association of <i>toll-like receptors</i> <i>2</i> and <i>6</i> polymorphism with clinical mastitis and production traits in Holstein cattle.

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