Bioscientifica Proceedings

The pig industry is confronted with substantial losses due to piglet mortality. With 3-8% stillbirths and generally > 10% preweaning mortality, approximately one fifth of al I fetuses formed fully at the end of gestation die before weaning. Most of these losses occur in the perinatal period. Overall prenatal development (birth weight) and specific prenatal developmental and maturational processes in late gestation are predisposing factors for perinatal losses. Birth weight ...

Declining fertility is a major problem for the dairy industry. Recent developments of Omics-technologies facilitate a comprehensive analysis of molecular patters in gametes, embryos and tissues of the reproductive tract which may help to identify the reasons for impaired fertility. Large Omics-datasets require appropriate bioinformatics analysis in the context of rapidly expanding and evolving scientific databases. This overview summarizes the current status of ruminant genome...

The capacity of pig uterine tissues to recognize and respond to maternal and conceptus signals determines whether pregnancy can be established and defines the environment in which embryonic and fetal growth occur. Limits of uterine capacity may be defined genetically. However, the extent to which functional uterine capacity approaches genetic potential may be determined, in part, by the success of organizational events associated with growth, morphogenesis and cytodiffere...

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...

Currently, there is no method to diagnose pregnancy non-invasively in most wildlife species that experience delayed implantation and pseudopregnancy, either during embryonic diapause or placental pregnancy. The aim of this study was to utilize farm-raised mink (Neovison vison) as a model species to evaluate changes in the fecal proteome associated with pregnancy. Specific objectives were to: 1) determine if fecal peptides were differentially abundant in parturient ver...

limiting factor to realizing the full potential of many of the new reproductive techniques is the lack of ahundant numbers of fertilizable oocytes. This problem could he addressed by using the large source of oocytes available from preantral and primordial follicles by developing systems for in vitro growth. In vitro systems that use early growing follicles as a source of oocytes have been developed for laboratory species and these have been successful ...

Summary. The consideration of the fetus as a semi-allograft by virtue of its paternally inherited histocompatibility antigens is generally accepted. Many hypotheses have been put forward to explain the immunological acceptance of the conceptus by the maternal immune system, but no single theory has proved to be adequate. Most studies so far have been carried out with laboratory rodents and men but corresponding investigations of farm animals and especiall...

The hypothalamic GnRH pulse generator that regulates intermittent GnRH discharge into the pituitary portal circulation and thereby modulates pulsatile secretion of LH has been recognized as a key determinant of the reproductive function in mammals. Thus, various internal, as well as external, factors first modify the electrical activity of the GnRH pulse generator, which then alters the pulsatile pattern of gonadotrophin secretion and eventually influences reproductive functio...

Summary. During pregnancy the hypothalamic–hypophysial axis is suppressed by the high concentrations of progesterone and oestradiol in the circulation. The high concentrations of these steroids appear to inhibit secretion of GnRH from the hypothalamus, resulting in inadequate stimulation of pituitary gonadotrophs to maintain synthesis of LH. This produces a depletion of LH in the anterior pituitary gland that must be restored after parturition before nor...

It has been suggested that the long-term reproduction of the sow is best served by minimizing weight and fat loss in lactation. Such a strategy would require only a minimal restoration of weight in the following pregnancy, which would be beneficial, since the greater feed intake and weight gain in pregnancy, the greater the weight loss in lactation. Feeding ad libitum should be practised during lactation while gestation feed intake must be held low. A relationship between...