Bioscientifica Proceedings

Neurophysiological mechanisms that control energy balance are reciprocally linked to those that control reproduction. Neuromorphological studies using retrograde tracing methods revealed that nerve cells within the central (CNS) and autonomic (ANS) nervous systems in different species, including the pig, are transsynaptically connected to different fat tissue depots. In the pig, neurons localised in the paraventricular nucleus, supraoptic nucleus and arcuate nucleus were...

Summary. Prolificacy has been defined as the number of viable piglets produced per year or per breeding lifetime. Prolificacy is influenced by age at first successful mating, ovulation rate and embryo survival at each mating, number of live born, viable pigs and the sow's ability to be successfully remated at regular intervals.It is concluded that under normal conditions of feeding and management nutrition will have a minimal influen...

Abstract unavailable© 1982 The authors...

Abstract unavailable© 1990 Journals of Reproduction & Fertility Ltd...

The mechanisms controlling the follicular growth continuum in the pig involve the interaction between local growth factors which are expressed throughout development and extra-follicular factors such as gonadotrophins. A large number of follicular growth factors, many belonging to the transforming growth factor-β (TGF-β) superfamily, have been identified in the somatic cells and in the oocyte. The relative importance of these intra-follicular factors varies wit...

Light microscopic semen evaluation provides useful information about a given sperm sample, but due to its subjective nature has limited prognostic value for the reproductive performance of males or the outcome of assisted fertilization. Cryptic sperm abnormalities (occurring at the molecular level) are not easily detectable by light microscopy, but can be revealed by an array of biomarkers. The latter include fluorescent markers of acrosomal status, fluorochromes detecting alt...

The bovine corpus luteum (CL) grows very fast and regresses within a few days at luteolysis. Mechanisms controlling development and secretory function of the bovine CL may involve many factors that are produced both within and outside the CL. In the cow, luteolysis is initiated by uterine prostaglandin (PG)F2α released at the late luteal stage. It can also be induced by injection of exogenous PGF2α given at the mid luteal stage. Luteolysis consi...

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

In the ruminant ovary, synthesis and secretion of oxytocin begin in the granulosa cells of the preovulatory follicle and are markedly stimulated by the surge of LH and FSH. Luteinization of the granulosa cells results in a further increase in oxytocin gene expression, but translation ol mRNA appears to be retarded because the peak concentration of luteal oxytocin occurs later than the maximal accumulation of the message. Several hormones have been shown to stimulate oxytocin s...

Summary. Exposure of male and female pigs to elevated ambient temperatures can result in reduced reproductive efficiency. When boars and gilts are exposed to heat stress, respiratory rates increase to enhance evaporative cooling because minimal sweating occurs.During early pregnancy, gilts are especially susceptible to heat stress. Decreased conception rates and reduced litter size occur when gilts are exposed to elevated ambient te...