A review on the influence of climate change on sheep reproduction

Increasing food and natural fibre production ensure food security for nearly 10 billion people, the projected global population in 2050, without causing further environmental damage can be achieved by transforming systems and adopting sustainable agriculture practices within a changing climate. Globally, climate change effects are having both direct and indirect effects on agricultural productivity including changing rainfall patterns, drought, flooding and the geographical redistribution of pests and diseases. Climate change induced heat stress is thus one of the complex factors making sheep management and husbandry challenging in many geographical locations in the world. Within the sheep industry, reproductive wastage (RW) is a major challenge throughout the varying breeding landscapes. Reproductive wastage is defined as the early losses of embryos undergoing natural and/or artificial breeding programs. Our previous research showed that heat stress (THI > 75) and elevated glucocorticoid levels (indexed using faecal glucocorticoid metabolites) are linked to embryo loss in Merino ewes. This mini review discusses how extreme variation in climate such as heat stress affects the maternal reproductive performance in the Merino sheep and the impacts on the wool industry. We provide recommendations to sheep producers for monitoring and managing the effects of heat stress on-farm.