Heat Stress Effects on Animal Health and Performance in Monogastric Livestock: Physiological Responses, Molecular Mechanisms, and Management Interventions.

Rising global temperatures driven by climate change have markedly increased the incidence of heat stress (HS) in monogastric livestock, posing critical challenges to animal welfare, health and productivity. This review provides a comprehensive analysis of the physiological and metabolic responses to HS in species such as poultry and swine. It details both the rapid thermoregulatory adaptations, including increased respiratory rate and peripheral vasodilation, and the sustained activation of the hypothalamic-pituitary-adrenal axis that elevates stress hormone levels. Chronic heat exposure disrupts immune function, induces oxidative stress via excessive reactive oxygen species production, and shifts metabolic balance from anabolic to catabolic processes, thereby impairing muscle development and compromising carcass composition. In response, a range of nutritional and management interventions, including antioxidant and osmolyte supplementation, dietary adjustments, enhanced housing designs, and genetic selection for heat tolerance, have been explored to mitigate these adverse effects. By integrating these multidisciplinary strategies, producers can improve animal welfare, sustain productivity, and preserve meat quality under escalating thermal challenges. The review further emphasizes the need for advanced monitoring technologies and precision livestock farming approaches to develop resilient, adaptive production systems in an era of climate uncertainty.