Analysis of the climatic trends and heat stress periods for ruminants rearing in Bangladesh

The production of ruminant livestock is greatly impacted by climate change, as it is anticipated to jeopardise food security due to the increasing heat stress experienced by the animals, which can be measured using the Temperature Humidity Index (THI). The objective of our study was to analyze climatic patterns, identify influential variables and evaluate heat stress episodes through the utilization of the THI to establish a rearing system for ruminants in Bangladesh. The THI value was determined by analyzing meteorological station data spanning from 1995 to 2022 across various climatic zones in Bangladesh. The Mann–Kendall evaluation was used to analyze the THI patterns throughout the study. Our findings indicated that heat stress problems are expected to occur in Bangladesh when THI for ruminant rearing exceeds 74, particularly from February to December. The severity of heat stress in THI_ruminant 71–90 varied significantly, ranging from normal to extremely severe. We observed that June (90) was the hottest month in the west central region, while January (71) was the coldest in the northwest area. When examining the impact of climatic factors on the THI, we found that air temperature has the highest influence, while relative humidity had the second-highest influence on THI in all areas of Bangladesh. Sunlight length and wind speed influenced the yearly THI marginally but not seasonally. Our findings highlighted a seasonal threat associated with heat stress in the climatic conditions of Bangladesh. It is essential to identify heat stress in ruminants, especially considering the continuing global warming issue. Our results recommend the implementation of heat stress mitigation strategies for ruminant farmers in Bangladesh.