Bioscientifica Proceedings

In this review the concept that the origins of embryonic failure occur during oocyte development is explored. The four factors that determine oocyte viability, namely a normal growth phase, adequate follicle cell support during maturation, the completion of intracellular reprogramming before fertilization and the functioning of oocyte surveillance mechanisms, form the four sections of this review. The viability of pig oocytes at the end of the growth phase is compromised...

Reduced reproductive efficiency has been reported in high-producing dairy cows. Sources of reproductive inefficiency include decreased expression of estrus, increased diameter of the ovulatory follicle and reduced fertility when cows are inseminated after estrus, increased incidence of double ovulation and twinning, and increased pregnancy loss. To overcome some of these inefficiencies, reproductive management programs have been developed that synchronize ovulation and enable ...

Over the past 30 years, basic and applied studies on classical and advanced embryo technologies have generated a vast literature on factors regulating oocyte and embryo development and quality. In addition, over this period, commercial bovine embryo transfer has become a large international business. It is well recognised that bovine embryos derived in vivo are of superior quality to those derived from in vitro maturation, fertilization and culture. Relatively little has chang...

Poor reproductive efficiency is a worldwide problem affecting the dairy industry. There is substantial evidence for an association between high milk production and lower conception rates observed in cows compared to heifers. However, whether the decline in fertility is due directly to the level of milk production or other factors associated with lactation is unclear. There are various checkpoints along the developmental axis which could, in part, contribute to reduced fertilit...

Embryonic diapause is a key strategy to extend pregnancy until conditions are ideal for birth and postnatal survival. There is still a lot to discover about this unique phenomenon observed in more than 130 mammalian species. The present review aims at complementing existing research efforts by (1) identifying new directions for a better understanding of embryonic diapause in mammals and (2) considering this complex mechanism as a source of inspiration for other areas in cellul...

Summary. Pig embryos enter the uterus from the oviduct about 48 h after ovulation at about the 4-cell stage. They remain near the tip of the uterine horn until about Day 6 when they migrate towards the body of the uterus. By Day 9 some embryos have entered the horn opposite the one of origin and continue migrating until Day 12. At Day 12 embryos can no longer successfully move to a different site. The critical signal for recognition of pregnancy occurs at...

Proteomic analysis occupies an increasingly important place in gamete and embryo biology as an independent tool of discovery and as a means of follow-up to transcriptional profiling. Proteomics have been and will be increasingly helpful in many areas of reproductive biology, including applied science and technology development. Areas likely to be impacted most rapidly by proteomic knowledge include fertility evaluation in male farm animals, male infertility diagnostics i...

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...

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...