Background/Objectives: Heat stress compromises cattle production, health, and welfare, but bovine transcriptomic studies span tissues and experimental settings. We sought gene-level effects and biological programs that recur across in vivo studies while preserving each study design. Methods: We uniformly reprocessed 107 bulk RNA-seq libraries from five Bos taurus studies, estimated heat-versus-control effects within study, and integrated log2 fold changes using restricted maximum-likelihood random-effects models. Modified Knapp–Hartung inference, prediction intervals, and Benjamini–Hochberg correction calibrated small-study uncertainty. A six-component heat-stress transcriptomic stability index (HSTSI), ten score definitions, five complete leave-one-study-out analyses, and directional enrichment assessed recurrence. Results: Among 16,756 genes, normal-approximation inference identified 19 at false-discovery rate (FDR) < 0.05, whereas none met FDR < 0.10 under modified Knapp–Hartung inference. IL1R2 ranked first by HSTSI (meta log2 fold change =0.82; 95% prediction interval, 0.31–1.33). Study deletion retained 68–117 of the top 200, and every estimable member preserved direction. IL1R2, SDCBP2, and GZMK were retained under all ten definitions and CD8A under nine. Proteostasis, translation, oxidative phosphorylation, and heat-response programs shifted positively; T-cell signaling, antigen presentation, cytotoxicity, cell-cycle, and small-GTPase programs shifted negatively. Of 266 full-data FDR-significant pathways, 259 retained direction in all five deletions and 21 remained FDR-significant throughout. Conclusions: Recurrence was strongest for coordinated biological programs. The graded candidate set supports tissue-matched validation without treating ranking as statistical significance.