Bioscientifica Proceedings

Abstract unavailable© 1982 The authors...

Efficient production of high quality semen is of major importance to artificial insemination (Al) organizations. The semen produced should be free of contagious organisms, be of high quality, have good storage properties, fertilizing capacity and be of high genetic value. The best approach to prevent the spreading of microorganisms via semen in the process of Al is to collect semen from boars free from specific diseases, for example pseudorabies virus or leptospirosis. An...

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...

Lactating sows are not able to ingest sufficient energy to produce the large amount of milk they are presently capable of. Therefore, sows use a considerable amount of body reserves to maintain their milk production. Body weight loss is negatively associated with subsequent reproductive performance. Addition of fat to the diet is often used to increase energy intake during lactation. This review examines the effects of adding fat to the diet on subsequent reproductive pe...

This review describes the role of boar stimuli in receptive behaviour, and the influence of boar stimuli during the follicular phase. Receptive behaviour (standing response) in an oestrous sow is elicited by boar stimuli, which can be olfactory, auditory, tactile, or visual. The relative importance of these stimuli is not clear. Individually, olfactory and tactile stimuli elicit a standing response in a variable percentage of sows, depending on the study, but not in all ...

The expression and localization of selected growth factor systems and extracellular matrix (ECM) components that may influence oocyte maturation and fertilization within the mammalian oviduct are reported. Fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) systems could be detected by use of RT–PCR, RNase protection assay (RPA) and immunohistochemistry in bovine follicles, bovine cumulus–oocyte complexes (COC) and bovine and marmoset oviduct...

Summary. Our understanding of the synthesis and production of follicular steroids and prostaglandins (PG) in the pig is based largely on in-vitro studies with granulosa and theca interna tissues obtained from Graafian follicles at various stages of maturation. As the follicle enlarges before the LH surge, granulosa cells exhibit a decrease in FSH receptors and are less responsive to FSH in terms of cAMP production. Concurrently, there is an increase in gr...

The development of new technologies that would increase the efficiency for generation of transgenic livestock and would overcome some of the problems associated with random insertion of the transgene will greatly benefit animal agriculture. A potential alternative technology to pronuclear injection for the generation of transgenic pigs involves the isolation, culture and genetic manipulation of cell lines that can be reintroduced into the embryo for participation in the f...

Abstract unavailable© 1995 Journals of Reproduction and Fertility Ltd...

Melatonin, which is synthesized at night by the pineal gland, is present in the cerebrospinal fluid (CSF), but its entry site and its role in this compartment are not known. Using several approaches, we tested the hypothesis that melatonin enters the CSF through the pineal recess, an evagination of the third ventricle. CSF melatonin concentrations are higher near the pineal gland than in the anterior part of the third ventricle, and decrease markedly (80%) after sealing of...