Bioscientifica Proceedings

The immune system discriminates 'self' from 'non-self', and eliminates that which it determines to be non-self. Mammalian pregnancy appears to represent a failure of self-non-self discrimination, yet it is a highly successful reproductive strategy. We present evidence that the immune system of the female pig responds to the challenges of both mating and the presence of conceptuses. Mating induces an influx of inflammatory leukocytes into the endometrial stroma and uterine...

The aim of this review is to pinpoint the areas that require further research for greatest impact to improve the efficiency of dairy and beef production. Increased knowledge about the principal causes of reduced fertility is essential. Increases in milk yield have been at the expense of reduced fertility in dairy cows and although diet has a major impact, the precise interaction between nutrition and reproduction still needs to be characterized in both beef and dairy cows. Fur...

Blastocyst activation, referring to the blastocyst acquiring the implantation competency, is the determining factor for implantation into the receptive uterus. It involves the process of embryonic cell differentiation to contact and initiate dialog with the uterine cells. Before the application of -omics approaches to this biological event, only the cellular morphological changes and a small number of molecules were known to regulate this process. This review aims to discuss t...

Abstract unavailable© 1990 Journals of Reproduction & Fertility Ltd...

On the basis of established surgical procedures for embryo recovery and transfer, the early pig embryo can be subjected to various manipulations aimed at a longterm preservation of genetic material, the generation of identical multiplets, the early determination of sex or the alteration of the genetic make-up. Most of these procedures are still at an experimental stage and despite recent considerable progress are far from practical application. Normal piglets have been ob...

The early morphological events in pig placental development are summarized and related to the known data on differences in placental vascular efficiency between Meishan and US breeds. The activation and localization of a number of factors, the ligands and their receptors, such as insulin-like growth factor (IGF), transforming growth factor β (TGFβ), platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF), as well as retinoids and cal...

Androgens have potential actions in almost all the organs of males and females. In females, most organs contain some tissues with cells that have androgen receptors. Androgens can regulate cellular functions by binding to androgen receptors or be converted to other hormones. For example, testosterone can bind to the androgen receptor or be aromatised to oestradiol. Treating animals with testosterone, therefore, might elicit some androgenic and oestrogenic effects. Altern...

In experimentally induced diapause model in mice, blastocysts remain dormant for an extended period but resume implantation competency upon estrogen injection. The underlying mechanism by which extended longevity of dormant blastocysts is maintained is unclear. We have previously shown that dormant blastocysts, during experimentally induced diapause, exhibit heightened autophagic activation. Activation of autophagy appears to be a crucial adaptive response for survival in the ...

The potential fertility of a sire can not be evaluated in the field simply by assessment of mating ability and physical examination, although these procedures can expose his limitations as a breeder. Finding a laboratory test that accurately estimates the potential fertility of a semen sample or a sire is also distant, as shown by the modest correlations that present tests have with fertility. Due to the complex nature of male fertility any sought for laboratory method must in...

Reproductive biology research on camelids offers some interesting peculiarities and challenges to scientists and animal production specialists. The objective of this paper is to review camelid reproduction, advances in reproductive physiology and reproductive biotechnologies in camelids and discuss some areas for further research. In the female, the focus has been on understanding follicular dynamics. This has allowed development of synchronization and superovulation strategie...