Heat stress is one of the most stressful events in the life of livestock with harmful consequences for animal health, productivity and product quality. Ruminants, pigs and poultry are susceptible to heat stress due to their rapid metabolic rate and growth, high level of production, and species-specific characteristics such as rumen fermentation, sweating impairment, and skin insulation. Acute heat stress immediately before slaughter stimulates muscle glycogenolysis and can result in pale, soft and exudative (PSE) meat characterized by low water holding capacity (WHC). By contrast, animals subjected to chronic heat stress, have reduced muscle glycogen stores resulting in dark, firm and dry (DFD) meat with high ultimate pH and high WHC. Furthermore, heat stress leads to oxidative stress, lipid and protein oxidation, and reduced shelf life and food safety due to bacterial growth and shedding. This review discusses the scientific evidence regarding the effects of heat stress on livestock physiology and metabolism, and their consequences for meat quality and safety.

热应激是牲畜生命中压力最大的事件之一，会对动物健康，生产力和产品质量产生有害影响。反刍动物，猪和家禽由于其快速的代谢速度和生长，高水平的生产以及特定于物种的特征（如瘤胃发酵，出汗障碍和皮肤绝缘）而容易受到热应激。屠宰前的急性热应激会刺激肌肉糖原分解，并可能导致肉色苍白，柔软和渗出（PSE），其特征是持水量（WHC）低。相比之下，遭受慢性热应激的动物的肌肉糖原储备减少，从而导致深色，坚硬和干燥（DFD）肉具有最高的最终pH和高的WHC。此外，热应激会导致氧化应激，脂质和蛋白质氧化，以及由于细菌的生长和脱落而降低了保质期和食品安全性。这篇综述讨论了有关热应激对牲畜生理和代谢的影响及其对肉品质和安全性的影响的科学证据。