Heat stress in livestock under tropical climates: impacts and mitigation strategies.

This review analyses the physiological and productive consequences of heat stress in tropical livestock and evaluates the mitigation strategies. Heat stress is a significant constraint in tropical production systems, where high temperatures, humidity, solar radiation, and variable wind conditions impose thermal loads that exceed animals’ capacity for heat dissipation. With global warming and more frequent heatwaves, high-yielding breeds selected for rapid growth and productivity are becoming increasingly vulnerable, resulting in significant impacts on welfare, health, and economics. Heat stress disrupts metabolic homeostasis, feed consumption, growth and reproductive efficiency. It also compromises product quality and behaviour. In dairy systems, one of the most sensitive indicators is milk yield reduction, with high-producing cows commonly experiencing losses of 10–30% under sustained thermal stress. Physiologically, heat stress induces endocrine imbalances and oxidative stress. These changes impair immune competence and productivity. These effects scale from individuals to herds, influencing food security and the sustainability of tropical livestock systems. Environmental strategies, including shading, ventilation, and evaporative cooling, reduce heat load and improve thermal comfort. Nutritional interventions aimed at enhancing antioxidant status and metabolic resilience, along with genetic selection for thermotolerance, offer additional benefits. Precision livestock farming technologies further support adaptive management through real-time monitoring and data collection, enabling informed decision-making. However, the effectiveness of these strategies depends on species-specific physiology, production intensity, and socio-economic feasibility. To address this, an integrated framework is required to guide future research and the design of cost-effective adaptation strategies in tropical livestock systems.