Location: Livestock and Range Research LaboratoryTitle: Loci and pathways associated with uterine capacity for pregnancy and fertility in beef cattle Author
|Mahesh, Neupane - Washington State University|
|Kiser, Jennifer - Washington State University|
|Burns, Gregory - University Of Missouri|
|Hansen, Peter - University Of Florida|
|Spencer, Thomas - University Of Missouri|
|Neibergs, Holly - Washington State University|
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2017
Publication Date: N/A
Interpretive Summary: Embryo mortality is a major factor that negatively affects fertility in cattle. Embryo loss is also very high in cattle, especially dairy cattle. Infertile and subfertile cows generally experience pregnancy loss during the first month of pregnancy. These females have lower production and economic efficiency. The goal of this study was to identify genetic markers related to pregnancy loss in cattle. This would allow screening of heifer calves before development as herd replacements. Thus, producers would be able to identify and develop only the most fertile heifers for their herd. We compared the genome of high fertility (100% pregnancy success) heifers with low fertility (= 25% pregnancy success) heifers. Pregnancy was diagnosed after repeated transfer of viable embryos. The roles of genes involved with these markers is also discussed. This study provides critical information for genomic selection to increase fertility in cattle.
Technical Abstract: Infertility and subfertility negatively impact the economics and reproductive performance of cattle. Of note, significant pregnancy loss occurs in cattle during the first month of pregnancy, yet little is known about the genetic loci influencing pregnancy success and loss in cattle. To identify quantitative trait loci (QTL) with large effects associated with early pregnancy loss, Angus crossbred heifers were fertility classified based on day 28 pregnancy outcomes to serial embryo transfer. A genome wide association analysis (GWAA) was conducted comparing 30 high fertility heifers with 100% success in establishing pregnancy to 55 subfertile heifers with 25% or less success. A gene set enrichment analysis SNP (GSEA-SNP) was performed to identify gene sets and leading edge genes influencing pregnancy loss. The GWAA identified 22 QTL (p < 1 x 10-5), and GSEA-SNP identified 9 gene sets (normalized enrichment score > 3.0) with 253 leading edge genes. Network analysis identified TNF (tumor necrosis factor), estrogen, and TP53 (tumor protein 53) as top of 671 upstream regulators (p < 0.001), whereas the SOX2 (SRY [sex determining region Y]-box 2) and OCT4 (octamer-binding transcription factor 4) complex was the top master regulator out of 773 master regulators associated with fertility (p < 0.001). Identification of QTL and genes in pathways that improve early pregnancy success provides critical information for genomic selection to increase fertility in cattle. The identified genes and regulators also provide insight into the complex biological mechanisms underlying pregnancy establishment in cattle.