Searchable, peer-reviewed, open-access proceedings from bioscience and biomedical conferences
Previous issue | Volume 4 | REDR1998 | Next issue

Reproduction in Domestic Ruminants IV

bp0004rdr22 | Embryonic Survival | REDR1998

Uterine differentiation as a foundation for subsequent fertility

Bartol FF , Wiley AA , Floyd JG , Ott TL , Bazer FW , Gray CA , Spencer TE

Uterine differentiation in cattle and sheep begins prenatally, but is completed postnatally. Mechanisms regulating this process are not well defined. However, studies of urogenital tract development in murine systems, particularly those involving tissue recombination and targeted gene mutation, indicate that the ideal uterine organizational programme evolves epigenetically through dynamic cell–cell and cell–matrix interactions that define the microenvironmental conte...

bp0004rdr23 | Embryonic Survival | REDR1998

IGF paracrine and autocrine interactions between conceptus and oviduct

Watson AJ , Westhusin ME , Winger QA

Development in vitro is influenced by embryo density, serum, somatic cell co-culture and the production of 'embryotrophic' paracrine and autocrine factors. Research in our laboratory has focussed principally on the insulin-like growth factor (IGF) family We have demonstrated that pre-attachment bovine and ovine embryos express mRNAs encoding a number of growth factor ligand and receptor genes including all members of the IGF ligand and receptor family througho...

bp0004rdr24 | Embryonic Survival | REDR1998

The regulation of interferon-τ production and uterine hormone receptors during early pregnancy

Mann GE , Lamming GE , Robinson RS , Wathes DC

During early pregnancy the bovine embryo must produce a protein called interferon τ which inhibits the development of the luteolytic mechanism. Failure to inhibit luteolysis is the major cause of pregnancy loss in cows. The embryo must produce sufficient quantities of interferon τ by about day 16 to prevent luteolysis. Its ability to achieve this is largely dependent on the pattern of maternal progesterone production. A late rise in progesterone after ovulation or po...

bp0004rdr25 | Embryonic Survival | REDR1998

Mechanism of action of interferon-tau in the uterus during early pregnancy

Hansen TR , Austin KJ , Perry DJ , Pru JK , Teixeira MG , Johnson GA

Early pregnancy is maintained in ruminants through the actions of conceptus-derived interferon (IFN)-tau on the endometrium. IFN-tau alters uterine release of PGF2α, which results in rescue of the corpus luteum and continued release of progesterone. The mechanism of action of IFN-tau includes inhibition of oestradiol receptors, consequent reduction in oxytocin receptors, activation of a cyclooxygenase inhibitor, and a shift in the PGs to favour PGE2 ...