In vitro prediction tests of fertility of frozen semen of sheep and cattle. Variation in fertility after artificial insemination (AI) of frozen semen is high and leads to economic loss. Routine assessment of the quality of frozen semen relies on crude, simple tests of motility and morphology of sperm. More sophisticated sperm ultrastructural and function tests have recently been developed, but it is not known how these tests relate to fertility in the field. In this project we will test a ran ....In vitro prediction tests of fertility of frozen semen of sheep and cattle. Variation in fertility after artificial insemination (AI) of frozen semen is high and leads to economic loss. Routine assessment of the quality of frozen semen relies on crude, simple tests of motility and morphology of sperm. More sophisticated sperm ultrastructural and function tests have recently been developed, but it is not known how these tests relate to fertility in the field. In this project we will test a range of in vitro methods of assessment of motility and morphology of sperm and compare them with fertility of frozen semen samples after AI, leading to more objective methods of semen analysis.Read moreRead less
Stimulation of the mammalian reproductive system by olfactory pathways. This project answers fundamental questions about mammalian reproductive biology but, because we work with the sheep model, our findings can be applied to two of Australia's biggest export industries, wool and sheepmeat. Understanding the reproductive responses of our production animals to exteroceptive factors such as socio-sexual signals, photoperiod and nutrition is an important first step towards refining the management ....Stimulation of the mammalian reproductive system by olfactory pathways. This project answers fundamental questions about mammalian reproductive biology but, because we work with the sheep model, our findings can be applied to two of Australia's biggest export industries, wool and sheepmeat. Understanding the reproductive responses of our production animals to exteroceptive factors such as socio-sexual signals, photoperiod and nutrition is an important first step towards refining the management of breeding programs. It has been argued that this approach will also minimise, and perhaps even remove the need for, exogenous hormones and drugs for controlling the reproductive process.Read moreRead less
Brain Regulation of Reproduction: Challenging the ‘KNDy’ Hypothesis. The brain switches reproduction on and off by changing the frequency of pulses of gonadotrophin releasing hormone. The processes that produce the pulses have been a puzzle for decades but, recently, brain cells that produce three peptides (kisspeptin, neurokinin B, dynorphin), known as ‘KNDy cells’, have been heralded as the ‘missing link’, or even the ‘pulse generator’. Using sheep, this project will challenge the KNDy hypothe ....Brain Regulation of Reproduction: Challenging the ‘KNDy’ Hypothesis. The brain switches reproduction on and off by changing the frequency of pulses of gonadotrophin releasing hormone. The processes that produce the pulses have been a puzzle for decades but, recently, brain cells that produce three peptides (kisspeptin, neurokinin B, dynorphin), known as ‘KNDy cells’, have been heralded as the ‘missing link’, or even the ‘pulse generator’. Using sheep, this project will challenge the KNDy hypothesis with pheromones and with acute increases in nutrition, two factors that rapidly increase the frequency of gonadotrophin releasing hormone pulses. The outcomes of this research are directly relevant to the optimisation of reproductive management in farm animals, wildlife and humans.Read moreRead less