Recent Advances in Understanding the Impact of Environmental Heat Stress on Sheep Production and Reproductive Performance: A Subtropical Climate Perspective

The subtropics are affected by severe climate change, which may induce heat stress in animals. Moreover, the region is significantly seasonal; hence, mitigating climate risks and implementing climate adaptation measures are necessary. Sustainable Development Goals 1, 2, and 13 call for no poverty, zero hunger, and climate action. These are the most severe problems affecting food security in the modern world. Food security refers to a situation in which all people have physical, social, and economic access to sufficient, proper, and healthy food that satisfies their dietary requirements. Nevertheless, the projected increase in the human population implies a greater demand for employment opportunities; hence, developing countries are building more industrial areas. The burning of fossil fuels in various industries potentiates climate change and environmental pollution. It is predicted that the ecological temperature will increase by almost 2.3–4.8 °C by 2100 due to climate change. Agriculture and animal products remain vital in Africa as drivers of the economy and transformation for sustainable livelihood and development. Sheep production has long been used as a source of income and livelihood and provides jobs for people who live in rural areas. It is also sometimes used for ritual ceremonies and to pay penalties to local authorities. Nevertheless, sheep have been identified to be sensitive to heat stress, characterized by low reproductive performance, low microbiota quantities, and poor general health. There are different strategies for mitigating heat stress; however, many smallholder farmers have limited access to education and lack the financial support required to incorporate artificial shade and plant trees for shade to limit heat stress. In this review, we aim to understand the effects of environmental heat stress on sheep production and reproductive performance. Based on this review, it can be concluded that heat stress can threaten food security if not addressed, especially for farmers who depend on sheep rearing. As a result, future studies are recommended to understand different adaptation methods that can be used to mitigate the heat stress effect on sheep productivity, reproductivity, and general health.