Bovine Pre-gastrulation Development and the role Of Rauber's Layer
type: CreativeWork
description: Although conception rates in cattle are estimated to be 90%, little over half of each insemination results in the birth of offspring. The majority of total combined foetal and embryonic loss is sustained between the bovine blastocyst hatching at Day 8 and the onset of gastrulation after Day 14. Post hatching, the bovine embryo develops a morphological architecture which is very different to the mouse, with a flat epiblast and the loss of the polar trophoblast, known as Rauber’s layer. In mice, the polar trophoblast is essential for the induction of gastrulation and the formation of the placenta. The pre-gastrulation layout of cattle embryos is shared by a diverse phylogeny of placental forming mammals, from rabbits to pigs, and it is therefore considered the more typical mode of mammalian embryonic development. Yet, compared to mouse embryonic development, relatively little is known about the gene expression and signalling networks required for successful gastrulation in these species, particularly cattle which are also economically important. This thesis studied the morphological and gene expression events during Days 11-15 in cattle which coincides with the period of greatest embryonic loss. A detailed morphological staging system is presented that is supported with spatio-temporal gene expression patterns of genes known to play fundamental roles in mouse pre-gastrulation development. Novel morphological structures and processes were identified such as the formation of the cattle anterior visceral hypoblast (equivalent to the mouse AVE) and cavitation of the epiblast in preparation for epithelialisation of this tissue. Both of these processes are considered pre-requisites for the induction of gastrulation in mammals. The spatio-temporal gene expression patterns prior to gastrulation showed overall high concordance with mouse development however, processes that lead to asymmetry in the mouse involving extra-embryonic tissues have diverged and this can be related ba…
abstract: Although conception rates in cattle are estimated to be 90%, little over half of each insemination results in the birth of offspring. The majority of total combined foetal and embryonic loss is sustained between the bovine blastocyst hatching at Day 8 and the onset of gastrulation after Day 14. Post hatching, the bovine embryo develops a morphological architecture which is very different to the mouse, with a flat epiblast and the loss of the polar trophoblast, known as Rauber’s layer. In mice, the polar trophoblast is essential for the induction of gastrulation and the formation of the placenta. The pre-gastrulation layout of cattle embryos is shared by a diverse phylogeny of placental forming mammals, from rabbits to pigs, and it is therefore considered the more typical mode of mammalian embryonic development. Yet, compared to mouse embryonic development, relatively little is known about the gene expression and signalling networks required for successful gastrulation in these species, particularly cattle which are also economically important. This thesis studied the morphological and gene expression events during Days 11-15 in cattle which coincides with the period of greatest embryonic loss. A detailed morphological staging system is presented that is supported with spatio-temporal gene expression patterns of genes known to play fundamental roles in mouse pre-gastrulation development. Novel morphological structures and processes were identified such as the formation of the cattle anterior visceral hypoblast (equivalent to the mouse AVE) and cavitation of the epiblast in preparation for epithelialisation of this tissue. Both of these processes are considered pre-requisites for the induction of gastrulation in mammals. The spatio-temporal gene expression patterns prior to gastrulation showed overall high concordance with mouse development however, processes that lead to asymmetry in the mouse involving extra-embryonic tissues have diverged and this can be related ba…
author: van Leeuwen, Jessica
keywords: embryology, gastrulation, cattle
license: https://researchcommons.waikato.ac.nz/bitstreams/a0998e91-cf4f-4913-9dab-281c0647a09f/download
date published: 2016
date modified: 2026-07-24T05:57:49Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Waikato