Bioscientifica Proceedings

Abstract unavailable© 2013 Context Products Ltd...

Placental insufficiency results in fetal loss, low birth weight, stillbirth, preweaning mortality and poor growth. Placental development begins at conceptus elongation, which is a primary factor controlling the size of the placenta. After elongation, the allantois develops outward from the embryo to establish the al lantochorion, which defines the size of the functional placenta. During implantation, chorionic trophoblasts adhere to endometrial epithelial cells. Placenta...

Summary. Southern blotting of bovine genomic DNA indicated the presence of at least 3 bovine tIFN genes. The full DNA sequence of one of these genes, thought to be expressed in trophoblast, has been determined, including 193 bp of 5' non-coding region. The inferred amino acid sequence of bovine tIFN is more similar to ovine tIFN (80%) than to bovine IFN-αII (70%). The 5' flanking sequence has some similarity with bovine IFN-&#94...

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

Primary cultures of luteal cells have been used to determine both acute and chronic effects of cytokines on luteal cell function and viability. Gonadotrophin-stimulated progesterone production is inhibited by interleukin 1β (IL-1β), tumour necrosis factor a (TNF-α), or gamma-interferon (IFN-γ), the last two cytokines being more effective than IL-I. In contrast, all three cytokines are potent stimulators of prostaglandin production by these cells. The mechan...

This review focuses on factors that may affect the sensitivity of the corpus luteum to uterine prostaglandin F2α, (PGF2α) and embryonic signals. The heterogeneity of the types of cell that are present within the corpus luteum results in complex interactions that ensure complete luteal regression in response to PGF2α. There is not likely to be a single factor that determines responsiveness. The sensitivity of the corpus luteum dep...

The oviduct controls the environment in which the gametes are transported and fuse, and in which embryonic development begins. The ultrastructural topography of the ampulla and isthmus is similar, consisting of ciliated and secretory cells, but a different array of proteins is secreted by each segment along with various serum components. Amino acids are selectively secreted by the oviduct; these amino acids probably interact with the gametes or embryo to facilitate the process...

Regulation of progesterone secretion from the corpus luteum during the oestrous cycle requires the integration of multiple signals to achieve the appropriate amount of progesterone to maximize reproductive efficiency. Development of a mature corpus luteum capable of secreting sufficient amounts of progesterone is dependent upon the pituitary hormones LH and growth hormone (GH). Continued secretion of progesterone from the mature corpus luteum is also dependent upon pituitary h...

The overall aim of this research was to improve fertility of cattle inseminated with sexed spermatozoa by improving sperm sorting procedures. Six field trials were conducted in which 4,264 heifers were inseminated into the uterine body with cryopreserved sexed or unsexed control spermatozoa. Pregnancy or calving rates with doses of 2 × 106 sexed spermatozoa ranged from 32 to 51%; these averaged 69% of the pregnancy rates with 20 × 106 un...

The capacity of pig uterine tissues to recognize and respond to maternal and conceptus signals determines whether pregnancy can be established and defines the environment in which embryonic and fetal growth occur. Limits of uterine capacity may be defined genetically. However, the extent to which functional uterine capacity approaches genetic potential may be determined, in part, by the success of organizational events associated with growth, morphogenesis and cytodiffere...