Frontiers in sheep reproduction - making use of natural responses to environmental challenges to manage productivity.

This review addresses advances, directions and opportunities for research on sheep reproduction in the context of the global challenges of food security and climate change, and demand for 'clean, green and ethical' (CGE) animal management. The foundation of CGE management is an understanding of the physiological processes through which the reproductive system responds to changes in the animal's environment. These days, to the main environmental factors (photoperiod, nutrition, pheromones), we need to add stress from extreme weather events.

Profiling patterns of fecal 20-oxopregnane concentrations during ovarian cycles in free-ranging southern white rhinoceros (Ceratotherium simum simum).

Unlike their wild counterparts, many white rhinoceros females in captivity fail to reproduce successfully such that current captive populations are not self-sustaining. The causes of the problem are poorly understood. Variation in cycle length and long periods of acyclicity are characteristics of the majority of these non-reproducing females in captivity but it is unknown whether these characteristics are a feature of reproductively successful free-ranging females.

Inhibition of the reproductive system by deslorelin in male and female pigeons (Columba livia).

Veterinary practitioners frequently encounter disorders of the reproductive system in avian patients. Management of these disorders relies on manipulating reproduction by modifying the environment, diet, and social interactions, and by the use of pharmacologic agents and surgery, with varying levels of success and side effects. An alternative is to use the gonadotropin-releasing hormone (GnRH) agonist deslorelin to suppress the pituitary-gonadal axis.