Heat Stress-Induced Phenotypic and Transcriptomic Shifts in Dairy Cows: Functional Validation of DNAJB1 as a Key Thermo-tolerant Gene

A high-temperature environment of 35°C ± 1°C with 60% humidity was simulated and maintained for 14 days in a climate-controlled chamber. During this period, physiological parameters, production performance, and blood biochemical indicators of the cows were measured.

The results demonstrated that under heat stress conditions, respiratory rates increased, milk yield significantly decreased, and overall production performance declined substantially. Building on the successful establishment of the heat tolerance model, subsequent genetic analyses were conducted on control and heat-stressed individuals. RNA-seq analysis of heat-stressed cows revealed heat response pathways and the core gene DNAJB1, which were not observed in the control group.