Bioscientifica Proceedings

© 2009 Society for Reproduction and Fertility...

© 2013 Context Products Ltd...

Summary. In many species the appearance of oestrus is sufficient to ensure that the time of ejaculation, sperm transport and capacitation are balanced with the time of ovulation. In the pig these phenomena vary considerably and require additional regulatory mechanisms which are partly explained by seminal components.Boar semen is rich in oestrogens (up to 11.5 μg/ejaculate). Infusion of saline with the addition of oestrogens in ph...

The structural and functional alterations of uterine epithelial cells that permit the apical-apical union of conceptus and uterine epithelium are complex and are likely to involve many different adhesion molecules with distinct but inter-related functions. A number of changes in the molecular composition at the apical surface of uterine epithelial cells associated with the transition from the pre-receptive to the receptive state in the pig uterus are reviewed. Molecules t...

Summary. Recent research clearly shows that fusion genes can be microinjected into a pronucleus of an ovum and integrate into the pig genome. Animals with such fusion genes are called ‘transgenic’. The percentage of injected ova that developed into transgenic pigs varied among experiments from 0.31% to 1.73%. The percentage of transgenic pigs that expressed the fusion gene ranged from 17% to 100%.Eleven different regulatory s...

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

Studies of low birth weight offspring have a long history in pig science. These pigs have reduced growth potential and poor carcass quality compared to their higher birth weight littermates. In contemporary commercial sows with between 10 and 15 total pigs born/litter, between-litter differences in average birth weight appear to make the largest contribution to variation in postnatal growth performance, independent of numbers born. Low birth weight is a characteristic of...

Summary. European breeds of rams appear to be responsive to photoperiodic changes even though there are large differences between breeds in the timing and amplitude of endocrine (LH and testosterone) and gametogenetic variations before the sexual season. Light regimens such as 6-month light cycles or alternations of constant short and long days every 12–16 weeks are able to entrain the parameters of sexual activity. In these regimens in which the period ...

The components of ruminant seminal plasma and their influence on the fertility of spermatozoa are reviewed. Seminal plasma can both inhibit and stimulate sperm function and fertility through the multifunctional actions of organic and inorganic components. These effects are now better understood because the composition of the seminal plasma, including its protein content and that of other structures, specifically membrane vesicles, has been clarified. Spermatozoa gain motility ...

High numbers of lipid droplets (LDs) in mammalian eggs are stored and maintained throughout embryo development without marked signs of their utilization. It was previously demonstrated in large domestic mammals that removing lipids from the zygote does not influence post-implantation development in terms of the rate of delivered offspring. Previously studied pig and cow eggs contain considerable amounts of LDs, while mice have a very low level of ooplasmic lipids, which allows...