BEYOND THE FARM GATE: WHY HEAT STRESS IN DAIRY COWS IS A PUBLIC HEALTH CRISIS

Author: KYLIE MCKEE

When we think about heat-related health crises, we typically envision vulnerable people—the elderly in un-air-conditioned homes, outdoor workers without adequate breaks, children in overheated classrooms. But there's another population experiencing dangerous heat stress at surprisingly moderate temperatures, and their suffering reverberates through our communities in ways we're only beginning to understand: dairy cows.

Recent research reveals that high-producing dairy cows experience heat stress at a Temperature-Humidity Index (THI) above 68—roughly equivalent to 22°C with 70% humidity. This is far more moderate than most people realize, and it's a threshold regularly exceeded across much of Australia and New Zealand during summer months. What happens when these animals suffer? The answer extends far beyond milk production figures and into the heart of rural community health, farmer wellbeing, and our collective climate resilience.