BioProject

The aberrant gene expression in the uterine endometrium and embryo has been the major causes of pregnancy failure in cattle. More...

The aberrant gene expression in the uterine endometrium and embryo has been the major causes of pregnancy failure in cattle. Therefore, selecting cows having adequate endometrial receptivity and embryos of better developmental competence based on the gene expression could increase the number of calves produced by in each cow during its productive life time. Overall design: We used endometrial and embryo biopsy technology in conjunction with the pregnancy outcome information to establish a direct link between the pre-transfer endometrial or in vivo derived embryo gene expression and pregnancy outcome after embryo transfer. Endometrial samples were collected from Simmental heifers at day 7 and 14 of the estrous cycle, one cycle prior to embryo transfer. In the next cycle, embryo biopsies consisting of 60-70% of inner cell mass and trophectoderm were transferred to the recipients at day 7 of the estrous cycle. The remaining 30-40% parts of the embryos were retained for analysis.Pregnancy diagnosis was performed at days 28 and 42 by ultrasonography and at day 56 by rectal palpation. Those heifers returned to heat at day 21 were considered as non pregnant or non receptive endometrium (NP) while those heifers ended up with successful pregnancy and calf delivery was considered as the calf delivery group or receptive endometrium (CD). Following this, the endometrial samples collected during the pre-transfer period and the embryo biopsies retained during embryo transfer were categorized based on the pregnancy outcome. Those endometrial biopsies collected at days 7 and 14 of the estrous cycle from heifers resulted in successful calf delivery were designated as CDd7 and CDd14, respectively and endometrial biopsies taken at days 7 and 14 of the estrous cycle from those subsequently resulted in no pregnancy were designated as NPd7 and NPd14, respectively. Similarly, the embryo biopsies were classified as those embryo biopsies resulted in successful calf delivery and those resulted in no pregnancy Less...