Hot and humid weather exposes animals to high temperature and relative humidity that ultimately reduce their ability to disperse body heat. To avoid serious consequences of heat stress, it is imperative to understand animal physiological responses and biochemical changes during a state of altered body homeostasis across different seasons of the year. This study evaluated seasonal dynamics of physiological, oxidative, and metabolic responses of Nili-Ravi buffaloes to hot and humid climate. Twenty non-lactating multiparous buffaloes were enrolled for this 1-year study. Meteorological data were recorded twice daily to calculate temperature humidity index (THI). Physiological parameters including rectal temperature (RT), body surface temperature (BST), and respiratory rate (RR) were measured weekly. Blood samples were collected once in each season (spring, summer, autumn, and winter) to analyze biochemical and antioxidant parameters. We also measured activities of liver enzymes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The results revealed a significantly higher THI value (82) during summer which resulted in a significant increase in RR and BST as compared to winter. Higher oxidative stress was observed in summer owing to significantly higher malondialdehyde (MDA) content and lower levels of serum antioxidant enzymes (GPx, SOD, and CAT) as compared to other seasons. Moreover, serum cortisol was also significantly higher while adrenocorticotropic hormone (ACTH), Triiodothyronine (T₃), insulin, and growth hormone contents were significantly lower in summer. Contrarily, plasma thyroxin (T₄) level was higher in summer. THI showed a positive correlation with physiological responses but a negative correlation with antioxidant parameters. Our study provides practical insights on the adaptive physiology of buffaloes and has several implications regarding the alleviation of heat stress in buffaloes to enhance the efficiency of production and reproduction under tropical climate. Our study suggests the use of appropriate cooling strategies to effectively manage the non-lactating buffaloes to avoid performance losses and animal welfare issues in summer season.

炎热潮湿的天气使动物暴露在高温和相对湿度的环境中，最终降低了它们散发体温的能力。为了避免热应激的严重后果，必须了解一年中不同季节身体稳态改变状态下动物的生理反应和生化变化。这项研究评估了尼利-拉维水牛对炎热和潮湿气候的生理、氧化和代谢反应的季节性动态。这项为期一年的研究招募了 20 头非哺乳期多产水牛。每天记录两次气象数据以计算温度湿度指数（THI）。每周测量包括直肠温度（RT）、体表温度（BST）和呼吸频率（RR）在内的生理参数。每个季节（春、夏、秋、冬）采集一次血样，用于分析生化和抗氧化参数。我们还测量了肝酶的活性，包括丙氨酸转氨酶 (ALT) 和天冬氨酸转氨酶 (AST)。结果显示，夏季的 THI 值 (82) 显着升高，这导致 RR 和 BST 与冬季相比显着增加。与其他季节相比，夏季氧化应激较高，因为丙二醛（MDA）含量显着升高，血清抗氧化酶（GPx、SOD 和 CAT）水平较低。此外，夏季血清皮质醇含量也显着升高，而促肾上腺皮质激素（ACTH）、三碘甲状腺原氨酸（T ₃ ）、胰岛素、生长激素含量显着降低。相反，夏季血浆甲状腺素（T ₄ ）水平较高。 THI 与生理反应呈正相关，但与抗氧化参数呈负相关。我们的研究为水牛的适应性生理学提供了实用的见解，并对缓解水牛的热应激以提高热带气候下的生产和繁殖效率具有多种意义。我们的研究建议使用适当的降温策略来有效管理非泌乳水牛，以避免夏季的性能损失和动物福利问题。