Bioscientifica Proceedings

The extensive use of embryo technologies has emphasized the need for assessing embryo quality by morphological techniques, such as transmission electron microscopy, immunocytochemistry for confocal laser scanning microscopy and fluorescence in situ hybridization. By a combination of these techniques, it has been possible to demonstrate: (i) that rRNA gene activation, as monitored by embryonic nucleolar development, is comparable in bovine embryos developed in vivo...

Somatic cell nuclear transfer (cloning) returns a differentiated cell to a totipotent status; a process termed nuclear reprogramming. Nuclear transfer has potential applications in agriculture and biomedicine, but is limited by low efficiency. To understand the deficiencies of nuclear reprogramming, our research has focused on both candidate genes (imprinted and X-linked genes) and global gene expression patterns in cloned bovine embryos/offspring as compared to those generate...

Summary. In four studies secretion patterns of LH, FSH, prolactin, testosterone and progesterone were measured in male and female cattle to determine endocrine changes associated with sexual maturation. Two periods of increasing gonadotrophin secretion were observed, the second one coinciding with puberty. A short luteal phase of 8–12 days precedes the first oestrus at 10–11 or 14 months of age. The testosterone values of the bulls increased with age...

Abstract unavailableKeywords: inhibin; oestradiol; cow; pig; FSH© 1991 Journals of Reproduction & Fertility Ltd...

There are many potential applications of transgenic methodologies for developing new and improved strains of livestock. One practical application of transgenic technology in pig production is to improve milk production or composition. The first week after parturition is the period of greatest loss for pig producers, with highest morbidity and mortality attributed to malnutrition and scours. Despite the benefits to be gained by improving lactation performance, little prog...

Embryogenesis is a complex process that is controlled at various levels. As new discoveries are made about molecular mechanisms that control development in other species, it is apparent that these same mechanisms regulate pig embryogenesis as well. Methylation of DNA and modification of histones regulate transcription, and mechanisms such as ubiquitinization, autophagy and microRNAs regulate development post-transcriptionally. Each of these systems of regulation is highl...

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

Abstract unavailable© 2013 Context Products Ltd...

An overview is presented on the structure and function of the pig oviduct in relation to sperm capacitation and oocyte development in vivo. In pigs, a functional sperm reservoir is established in the uterotubal junction-isthmus when sperm deposition occurs before ovulation. Capacitation is assumed to occur in this location, and spermatozoa progress towards the ampullaryisthmic junction at about the time of ovulation as a consequence of capacitation and hyperacti...

Embryo technological procedures such as in vitro production and cloning by nuclear transfer are not as advanced in pigs as in cattle and cannot yet be applied under field conditions. The present paper focuses on genome activation in in vivo-derived, in vitro-produced and nuclear transfer pig embryos with special emphasis on the development of embryonic nucleoli, where the ribosomal RNA (rRNA) genes transcribed can be used as markers for genome ...