Bioscientifica Proceedings

As stated in the first Proceedings, the economically important domestic species have been the subject of ongoing reproductive research over many decades. The aims of researchers and clinicians have been directed at increasing fecundity and fertility, to manipulate reproduction for simpler management, to increase the genetic influence of selected individuals and importantly to improve animal welfare. A group of international researchers initiated the first symposium in Australi...

As stated in the first Proceedings, the economically important domestic species have been the subject of ongoing reproductive research over many decades. The aims of researchers and clinicians have been directed at increasing fecundity and fertility, to manipulate reproduction for simpler management, to increase the genetic influence of selected individuals and importantly to improve animal welfare. A group of international researchers initiated the first symposium in Australi...

Abstract unavailable© 1982 The authors...

Summary. In many species the appearance of oestrus is sufficient to ensure that the time of ejaculation, sperm transport and capacitation are balanced with the time of ovulation. In the pig these phenomena vary considerably and require additional regulatory mechanisms which are partly explained by seminal components.Boar semen is rich in oestrogens (up to 11.5 μg/ejaculate). Infusion of saline with the addition of oestrogens in ph...

Abstract unavailable© 1987 Journals of Reproduction & Fertility Ltd...

Nutritional signals are detected by the central nervous system (CNS) and translated by the neuroendocrine system into signals that alter secretion of LH and growth hormone (GH). Furthermore, these signals directly affect the activity of the pituitary gland independently of CNS input. Insulin-like growth factor I (IGF-I), insulin, leptin and specific metabolites, such as glucose and free fatty acids (FFA)', are potential signals of the metabolic status to the brain-pituit...

Secreted peptide hormones and components of the steroidogenic machinery are molecules that are expressed usually in high amounts and in a time- and cell-specific fashion within the cells that give rise to the bovine corpus luteum. They thus serve as useful markers for the events occurring within the nuclei of these cells that result in differentiation and the expression of the specific luteal phenotype. We have studied the bovine genes of three such luteal products: oxytocin, ...

Summary. In the ram, the size of the testes is related to the concentrations of FSH, LH and testosterone in the blood. A significant linear relationship is observed between testicular size and the level of FSH until a maximum after which no further increase in testis size is observed. Testicular size is also linearly related to the mean level (25 consecutive hours of sampling) of LH and testosterone in the blood, with apparently no upper limit, and to the freq...

In nuclear transfer reconstructed embryos, the co-ordination of donor nuclear and recipient cytoplasmic cell cycle phases is essential to maintain ploidy and prevent DNA damage. However, the stage of the cell cycle at the time of reconstruction and the method of reconstruction may also have a significant impact on the subsequent development of the embryo and fetus through a number of other mechanisms. This paper reviews some of the information currently available and proposes ...

For a follicle to reach dominance, in mono-ovulatory species such as cattle, requires the integration of a number of processes involving both extra-ovarian signals and intra-follicular paracrine and autocrine regulators. Ovarian transplant studies in both cattle and sheep demonstrated that it takes approximately 4 months for primordial follicles to reach dominance. Gonadotrophins are not a prerequisite for the continued growth of pre-antral follicles, unlike antral folliclcs, ...