Heat stress is one of the most significant welfare and productivity challenges in dairy farming, with climate change increasing its frequency and severity across traditional dairy regions worldwide.
Heat stress causes multi-system physiological compromise in dairy cows. Beyond reduced production, heat-stressed cows experience elevated body temperatures, discomfort, behavioral changes including reduced activity and increased time standing near water, and compromised immune function. Chronic heat stress impairs reproductive performance, causing significant welfare harm through failed pregnancies and the associated physiological burden of repeated reproductive cycles. The cumulative welfare impact across a lactation is substantial. Modern dairy operations in hot regions increasingly invest in cooling infrastructure, not only for productivity reasons but as a recognized welfare obligation. As climate change intensifies heat stress risk, proactive investment in cooling becomes increasingly urgent both economically and ethically.