Bioscientifica Proceedings

The complexity of implantation necessitates intimate dialogue between conceptus and maternal cells, and precise coordination of maternal and conceptus signalling events. Maternal and conceptus-derived steroid hormones, growth factors and cytokines, as well as integrins and their ligands, have important and inter-related roles in mediating adhesion between apical aspects of conceptus trophectoderm and maternal uterine luminal epithelium that leads to formation of an epithelioch...

The introduction of high-density SNP arrays in livestock species has enabled genomic evaluations on a scale not possible just a few years ago. Faster genetic gains are realized from application of genomics in pigs by increasing the accuracy of selection. This is especially important for lowly heritable reproductive traits, where female selection candidates have not yet expressed a phenotype at the point of selection and male candidates have no phenotype at all. Litter si...

The introduction of high-density SNP arrays in livestock species has enabled genomic evaluations on a scale not possible just a few years ago. Faster genetic gains are realized from application of genomics in pigs by increasing the accuracy of selection. This is especially important for lowly heritable reproductive traits, where female selection candidates have not yet expressed a phenotype at the point of selection and male candidates have no phenotype at all. Litter si...

The extensive use of embryo technologies has emphasized the need for assessing embryo quality by morphological techniques, such as transmission electron microscopy, immunocytochemistry for confocal laser scanning microscopy and fluorescence in situ hybridization. By a combination of these techniques, it has been possible to demonstrate: (i) that rRNA gene activation, as monitored by embryonic nucleolar development, is comparable in bovine embryos developed in vivo...

Summary. Despite apparent progress in reproductive technology as applied to wild ruminants, the success achieved in terms of the number of offspring that become healthy adults has remained low. Difficulties often arise through a lack of knowledge regarding appropriate cryopreservation techniques, and indeed through a lack of detailed information on the reproductive physiology of the species in question. The Spanish ibex (Capra pyrenaica) is a wild cap...

Summary. Reproductive traits can range from lowly to moderately heritable. Genomic technologies provide a powerful tool for improving selection for traits that are lowly heritable, sex-linked, or not expressed until later in life. Therefore, as genomic technologies become a part of selection decisions, there is a critical need to understand how specific gene variants affect reproductive traits in cattle. Both classical quantitative genetics approaches and geno...

Summary. Development of the corpus luteum (CL) is vital for the early increase in postovulatory progesterone that drives embryo development and the successful establishment of pregnancy. Following ovulation, rapid and dramatic cellular reorganisation and intense angiogenesis are required to support the timely transition to progesterone secretion. In addition to inherent physiological challenges, this process is sensitive to any imbalance in metabolism or healt...

Embryo transfer (ET) should play a critical role in the pig industry because it allows the movement and introduction of new genetic material into a herd with minimal risk of disease transmission and reduced transportation costs. In addition, embryo movement could prevent the potential health and welfare problems associated with transporting live pigs. Although the first successful ET was reported more than 60 years ago, the commercial use of this procedure in pigs is sti...

Summary. During folliculogenesis a group of growing preantral follicles becomes responsive and dependent upon gonadotrophins, especially FSH, for their continued growth and differentiation. However, most of these follicles undergo atresia. The mechanisms that result in survival of a specific number of ovulatory (dominant) follicles appear to depend upon: (a) responsiveness of preantral follicles to gonadotrophins, (b) inhibitory and stimulatory factors from a ...

Timing of conceptus growth and attachment to the uterine luminal epithelium is regulated by progesterone secretion from the corpus luteum and by expression of progesterone receptor in the uterine epithelia and stroma. Conceptus growth and uterine attachment are temporally associated with the disappearance of progesterone receptors from uterine epithelia. While the loss of progesterone receptor from the endometrial epithelia on day 10 of the oestrous cycle and pregnancy h...