Heat stress in riverine buffaloes: regulatory mechanism, physiological changes, production and reproductive performance, and mitigation strategies.

Buffalo is playing a leading role in the national economy by producing milk, meat and draught power in Pakistan. According to the Economic Survey of Pakistan (2023-24), buffalo contributes about 59.6%, followed by cattle (37.4%) and sheep/goat/camel (3%). The climatic conditions of tropical areas are primarily characterized as hot and humid. High ambient temperatures, mainly, are a significant factor affecting animals in tropical and subtropical regions. Due to high temperatures and moisture, heat stress is the main force hindering buffalo productivity in tropical regions. High ambient temperatures contribute to reproductive failures and embryonic mortality, especially in buffalo. Heat stress also reduces feed intake while alarmingly decreasing milk yield. Furthermore, one of the major factors affecting infertility in tropical areas is heat stress, and buffaloes require an effective, applicable strategy to combat these problems in buffaloes for increasing breeding efficiency and health condition. However, there is limited research on this topic in buffaloes, particularly associated genes involved in stress-related pathways. Therefore, this review summarizes the consequence of heat stress on the production and reproduction performance of riverine buffaloes. Moreover, practical insights about the adaptive physiology is narrated. Furthermore, potential strategies for heat stress mitigation were discussed in order to reduce negative effects on production performance and buffalo welfare. Future perspectives on the potential of nutrigenomic interventions for the targeted improvement of adaptive physiology in buffalo to cope with heat stress to ensure sustainable buffalo production in tropical areas are also discussed.