Heat stress in farm animals causes profound welfare impacts and economic losses. As climate change intensifies, understanding and mitigating heat stress is a growing priority for animal agriculture.
Heat stress causes suffering across multiple physiological systems. Animals experience elevated heart and respiration rates, reduced appetite, and in severe cases, heat stroke with hyperthermia, neurological signs, and death. The welfare burden falls most heavily on high-producing dairy cows, fast-growing broilers, and pregnant sows whose metabolic heat production exacerbates environmental heat loading. The irony that intensive production systems generating the most greenhouse gases also produce animals most vulnerable to heat stress creates a profound welfare-sustainability paradox. Proactive cooling infrastructure, modified management during heat events, and longer-term breed selection for heat tolerance are essential welfare responses.