Bioscientifica Proceedings

Summary. The control and induction of ovulation in cattle are discussed with particular reference to use of progesterone-impregnated coils in heifers and beef cows. Progesterone treatment for 14 days was required to obtain precise onset of oestrus. With 7, 9 or 12 days of progesterone treatment a luteolytic agent in the form of a prostaglandin (PG) or oestradiol benzoate had to be used. Fertility was normal after treatment durations of 7, 9 or 12 days, but fer...

The resting pool of primordial follicles in mammalian ovaries is a potential resource for the genetic manipulation of domestic animals, the preservation of endangered species, and the amelioration of some forms of infertility in humans. Exploitation of this large reservoir of follicles depends on the development of methods for activating primordial follicles to begin growth in vitro and of methods for sustaining follicular growth to the stage at which oocytes are capa...

Animals adjust the time of year that they reproduce through their ability to perceive and respond to critical aspects of their environment, such as photoperiod, nutrition or the socio–sexual milieu, and their genotype determines the degree of response to each stimulus. Ultimately, information from environmental cues filters through to the GnRH neurones in the brain which are the primary regulator of fertility. Each of these cues has been studied in isolation and the mech...

The objective of this study was to investigate the precocious sexual maturation in stoat females. We confirmed oestrus and successful mating in newborn stoats; and documented ovulation, preimplantation embryo development, embryonic diapause and implantation during first nine months of life. A total of 100 embryos at different stages of development were flushed from the oviducts and uterine horns obtained from female stoats (Mustela erminea) between day 26 and day 251 ...

Keywords: counter current transfer; ovary; oviduct; uterus; pig© 1990 Journals of Reproduction & Fertility Ltd...

Research in France and in the UK confirms the prolificacy of the Chinese Meishan breed to be about three to four piglets greater than that of control Large White females. Crossbreeding studies clearly indicate that this breed difference is due to genes acting in the dam and not in the litter itself. There is high heterosis for litter size in F1 Meishan x Large White crossbred females, such that their litter size is similar to or greater than that of purebred Me...

Litter size is often proposed as the trait that could have the greatest impact in improving reproductive efficiency of pigs. Efforts to select directly for increased litter size have generally been unsuccessful and highly variable. As a result, several attempts have been made to identify critical physiological components that control litter size, with the underlying assumption that augmenting these components would improve this important trait. One attempt at improving p...

Insemination transmits to the female reproductive tract constituents of seminal plasma that target uterine epithelial cells to activate a cascade of inflammatory and immunological changes. Experiments in rodents show seminal factor signalling acts to 'condition' the female immune response to tolerate the conceptus, and to organise molecular and cellular changes in the endometrium to facilitate embryo development and implantation. The active factors in seminal plasma are ...

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...

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