Searchable, peer-reviewed, open-access proceedings from bioscience and biomedical conferences

bp0004rdr11 | Comparative Reproductive Function: Implications for Management | REDR1998

Comparative reproductive function in cervids: implications for management of farm and zoo populations

Asher GW , Monfort SL , Wemmer C

The cervids represent a complex assemblage of taxa characterized by extreme diversity in morphology, physiology, ecology and geographical distribution. Farmed species (for example red deer and fallow deer) are usually the common larger-bodied, gregarious and monotocous species that express marked reproductive seasonality in their temperate environment. Their commercial importance has facilitated considerable research into reproductive physiology and the development of assisted...

bp0013cpr1 | The Hypothalamic-Pituitary-Ovarian Axis | CPR1989

Hypothalamic control of gonadotrophin and prolactin secretion in pigs

Kraeling R. R. , Barb C. R. ,

Keywords: hypothalamus; gonadotrophin; prolactin; pig; neurocndocrine© 1990 Journals of Reproduction & Fertility Ltd...

bp0014cpr13 | Reproductive Management | CPR1993

Seasonal effects on fertility in gilts and sows

Love R. J. , Evans G. , Klupie C. ,

The ancestral wild pig is a short day length seasonal breeder. The domestic pig appears to have retained some of this seasonality as evidenced by a reduction in fertility during the summer—autumn period. The most important aspect of this seasonality is a reduction in the number of mated sows that farrow. Many of these sows conceive and embryos develop normally for 20 - 25 days before pregnancy is terminated and the sow returns to oestrus (25 - 35 days after mating). In ot...

bp0014cpr17 | Components of Prolificacy in Pigs | CPR1993

Genetic basis of prolificacy in Meishan pigs

Haley C. S. , Leel G. J.

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...

bp0014cpr19 | Components of Prolificacy in Pigs | CPR1993

Earlyembryonic development in prolific Meishan pigs

Ford S. P. , Youngs C. R. ,

Prenatal mortality in European pigs is estimated at 30-40%, the majority of which occurs between days 12 and 18 after mating. Chinese Meishan pigs are prolific, averaging three to five more pigs per litter than do European breeds. Early reports into the fecundity of Meishan females suggested that their prolificacy resulted from lower embryonic mortality when compared with European females exhibiting the same ovulation rate. The preponderance of evidence suggests that ther...

bp0016cpr5 | OOcyte Development in vitro and in vivo | CPR2001

Mammalian gonadal differentiation: the pig model

Pailhoux E. , Mandon-Pepin B. , Cotinot C.

In mammals, testicular differentiation is initiated by SRY (the sex-determining region of the Y chromosome) gene expression in Sertoli cell precursors, followed by upregulation of the SOX9 gene (SRY-related HMG box gene 9). Subsequently, differentiated testis produces two hormones that induce sexual differentiation of the internal and external genital tract. Knowledge of the molecular mechanisms involved in gonadal differentiation has increased greatly over the past deca...

bp0008rdr23 | Corpus Luteum | REDR2014

Corpus luteum development and angiogenesis

Robinson Robert S , Woad Katie J , Hunter Morag G , Sinclair Kevin D , Laird Mhairi , Joseph Chitra , Hammond Amanda J , Mann George E

Summary. Development of the corpus luteum (CL) is vital for the early increase in postovulatory progesterone that drives embryo development and the successful establishment of pregnancy. Following ovulation, rapid and dramatic cellular reorganisation and intense angiogenesis are required to support the timely transition to progesterone secretion. In addition to inherent physiological challenges, this process is sensitive to any imbalance in metabolism or healt...

bp0002rdr20 | Oocyte Maturation | REDR1990

Derivation of pluripotent, embryonic cell lines from the pig and sheep

Notarianni Elena , Galli C , Laurie S , Moor RM , Evans MJ

Summary. As previously described for the establishment of stable, pluripotent cell lines from pig blastocysts, an analogous cell line was isolated from a sheep blastocyst. There are common features in the morphologies and growth characteristics of the pig and sheep cells in culture; in particular, pig and sheep cells display large nuclei and relatively sparse cytoplasm, as is observed in mouse embryonic stem cells. Furthermore, the morphology of the sheep cell...

bp0005rdr34 | Ruminant Models for Human Clinical Medicine | REDR2002

The differential secretion of FSH and LH: regulation through genes, feedback and packaging

McNeilly AS , Crawford JL , Taragnat C , Nicol L , McNeilly JR

While the role of oestradiol and progesterone in the control of GnRH pulsatile secretion and generation of the preovulatory GnRH surge to induce release of the LH surge has been fully investigated, less attention has been given to changes in the pituitary gland that may sensitize gonadotrophs to switch from pulsatile release to surge release of LH, in particular. Furthermore, in the follicular phase while pulsatile secretion of LH is maximal, FSH secretion is reduced, yet both...