Heat Stress in Sheep Production Under Climate Change: Physiological, Reproductive, Productive and Climate Resilience Perspectives

Climate change and increasing thermal pressure represent major long-term challenges for sheep production, particularly in climate-vulnerable regions and production systems. Heat stress can alter thermoregulatory, metabolic, endocrine, reproductive, oxidative, and immune responses, with consequences for animal health, welfare, and productive performance. This review critically evaluates current evidence on the biological and production-related consequences of heat stress in sheep and examines nutritional, genetic, environmental, health-management, and precision-monitoring approaches within a climate-resilience framework. The evidence indicates substantial variation in the magnitude and persistence of heat-stress responses according to breed or genotype, physiological and nutritional status, production system, and the intensity, duration, and timing of thermal exposure. Controlled studies provide important mechanistic insight, whereas field studies capture commercial complexity but are more strongly influenced by concurrent nutritional, climatic, health, and management factors. Nutritional, genetic, environmental, and precision-monitoring interventions offer opportunities to support adaptation, but their effectiveness and transferability across production systems require further validation. Improving climate resilience will therefore require context-specific combinations of complementary strategies rather than uniform solutions. Major research priorities include long-term field evaluation, improved comparability of heat-stress assessment, investigation of concurrent stressors, and evaluation of the practical and economic feasibility of adaptation and mitigation measures under commercial conditions.