Bioscientifica Proceedings

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. The progress in understanding the metabolism of the ruminant cumulus-oocyte complex (COC) from large antral follicles has progressed significantly in the past decade. In particular, new insights in the importance of lipid metabolism, ß-oxidation and its relationship to oxidative phosphorylation within oocytes have emerged. This provides opportunities for tapping into the potential yield of ATP from lipid metabolism, as ATP content is a major dete...

Summary. European breeds of rams appear to be responsive to photoperiodic changes even though there are large differences between breeds in the timing and amplitude of endocrine (LH and testosterone) and gametogenetic variations before the sexual season. Light regimens such as 6-month light cycles or alternations of constant short and long days every 12–16 weeks are able to entrain the parameters of sexual activity. In these regimens in which the period ...

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...

Placental insufficiency results in fetal loss, low birth weight, stillbirth, preweaning mortality and poor growth. Placental development begins at conceptus elongation, which is a primary factor controlling the size of the placenta. After elongation, the allantois develops outward from the embryo to establish the al lantochorion, which defines the size of the functional placenta. During implantation, chorionic trophoblasts adhere to endometrial epithelial cells. Placenta...

Abstract. During the last decade, transcriptome profiling has emerged as an efficient approach to describe and study cellular functions. The potential to survey transcript abundance for all genes offers promise to shed light on mammalian early embryogenesis. Furthermore, the report of aberrant phenotypes following the application of reproductive technologies also fueled the need to understand how embryos react, cope and adapt to their surrounding microenvironm...

While the role of oestradiol and progesterone in the control of GnRH pulsatile secretion and generation of the preovulatory GnRH surge to induce release of the LH surge has been fully investigated, less attention has been given to changes in the pituitary gland that may sensitize gonadotrophs to switch from pulsatile release to surge release of LH, in particular. Furthermore, in the follicular phase while pulsatile secretion of LH is maximal, FSH secretion is reduced, yet both...

There are many potential applications of transgenic methodologies for developing new and improved strains of livestock. One practical application of transgenic technology in pig production is to improve milk production or composition. The first week after parturition is the period of greatest loss for pig producers, with highest morbidity and mortality attributed to malnutrition and scours. Despite the benefits to be gained by improving lactation performance, little prog...

Abstract unavailable© 2009 Society for Reproduction and Fertility...

Abstract unavailable© 2009 Society for Reproduction and Fertility...