Bioscientifica Proceedings

Spermatozoa fulfil a single role, namely achieving syngamy by transporting the haploid genome to their counterpart gamete, the oocyte. Simple as this may seem, it is fraught with many difficulties, especially in the face of biological processes that enable females to select spermatozoa after they have mated multiply with several males. Conversely, the female reproductive tract sequesters a privileged sperm subpopulation in the oviductal isthmus for variable periods of ti...

Embryo transfer (ET) should play a critical role in the pig industry because it allows the movement and introduction of new genetic material into a herd with minimal risk of disease transmission and reduced transportation costs. In addition, embryo movement could prevent the potential health and welfare problems associated with transporting live pigs. Although the first successful ET was reported more than 60 years ago, the commercial use of this procedure in pigs is sti...

Summary. Changes in uterine blood flow throughout pregnancy appear to be due to steroid-induced alterations in uterine arterial tone and contractility. Arterial contractility is a transient reduction in luminal diameter in response to nerve stimulation or to an alpha-1 adrenergic agonist, leading to short-term reduction in uterine blood flow. Tone is the pressure exerted by an arterial segment against an intraluminal flow (distensibility) and is considere...

Summary. Behavioural responses can have direct effects on reproduction when the performance of the behaviour contributes to productivity (e.g. achievement of copulation). Alternatively, there are indirect effects where a behavioural change is insufficient to allow adaptation to an environmental change and so the animal has to resort to physiological mechanisms with potential adverse effects on productivity.Boar contact has substantial ...

The uterus plays a central role in the reproductive biology of mammals. Adaptation of the uterus from an oviparous to a viviparous nature required changes that involved production of a uterine environment that could support the development of the embryo and fetus. Production of a suitable environment includes the synthesis and secretion of products by the uterine endometrium. However, the uterine endometrium is not a single homogeneous unit, but rather consists of several...

Abstract unavailable© 2013 Context Products Ltd...

Abstract unavailable© 2013 Context Products Ltd...

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

The Meishan pig provides a biological model with the genetic capacity to express a high prolificacy. This prolificacy can be partially attributed to a higher ovulation rate and a higher rate of prenatal survival at a given ovulation rate throughout gestation than in European breeds. Both early embryonic survival (factors inherent to the ovum and uterus, which occur before day 25 of gestation) and uterine capacity (factors inherent to uterine limitation, which occur from 3...

A review of the remarkable production of steroids by the testes of the boar is presented, with the principal aims of highlighting the achievements of the Leydig cells and, at the same time, pointing to the considerable deficiencies in our understanding of its biological relevance. The onset of gonadal steroidogenesis at an early stage of sex differentiation and the pattern of pre- and postnatal secretion of steroids are outlined. This is followed by a list of steroids id...