Bioscientifica Proceedings

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

Summary. It is proposed that the first follicular phase in the lamb is initiated when responsiveness to oestradiol inhibition of LH secretion decreases sufficiently to permit the expression of an inherent hourly LH pulse rhythm. The hourly LH pulse rhythm is believed to drive oestradiol production to levels that induce the first LH surge. This hypothesis is based upon several considerations. First, pulsatile LH secretion invariably occurs at low frequencies in...

Summary. Data on the structure, quantitation, origins and functions of the large luteal (LL) and small luteal (SL) cells of sheep, goats and cattle are reviewed. Both LL and SL cells show ultrastructural features consistent with a steroidogenic function. However, in addition to differences in size and shape, LL cells differ from SL cells primarily in possessing large numbers of secretory granules, suggesting an additional protein/polypeptide synthetic and secr...

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

Keywords: lactation; weaning; sow; endocrinology; suckling© 1990 Journals of Reproduction & Fertility Ltd...

In some situations, the pig has advantages over the mouse as a model in biomedical research. The availability of pluripotent cell lines is likely to broaden this appeal. Here we review progress in the derivation and characterization of embryonic stem cells (ESC) and induced pluripotent lines (iPSC) from pigs. Until recently, most porcine ESC failed to meet the full criteria for pluripotency, but that may be changing as more becomes known about the culture conditions requ...

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

A successful mating involves the coordination of many physiological events including insemination, gamete transport and ovulation. As more basic information about these processes becomes available, it is apparent that there are opportunities for manipulating these physiological events and enhancing the reproductive success of natural and artificial matings. The primary intent of this review is to examine the effectiveness of several of these strategies, as determined by t...

Abstract unavailable© 2013 Context Products Ltd...

Recent publication of the sequence of the pig genome allows for faster and more accurate selection for traits expressed late in life, sex limited or difficult to measure. Especially reproduction and adaptation traits fall in this category. Existing genetic variation in reproduction traits is substantial and polygenic selection has resulted in genetic trend of around half a piglet per sow per year. A very significant increase in genetic trend is anticipated through genomi...