Thermal Stress in Livestock During Heat Waves

Climate change is increasing the frequency and severity of heat waves that cause significant suffering and mortality in farm animals. Proactive management prevents predictable welfare crises.

Key Facts

Heat stress begins in cattle when temperature-humidity index (THI) exceeds 72
Dairy cows experiencing heat stress produce 10-25% less milk and have lower reproductive rates
Heat stress in pigs increases mortality significantly and causes severe welfare impacts
Poultry are particularly vulnerable - broiler chickens begin dying at sustained temperatures above 35C
Shade, ventilation, and water availability are the three critical interventions for livestock heat stress
Climate change is projected to increase heat stress days for US livestock by 50-100% by 2100
White feathered broilers absorb less solar radiation than dark birds, making shade more critical for them

Welfare Considerations

Heat stress in farm animals causes suffering that ranges from chronic discomfort reducing productivity and welfare to acute lethal events during extreme heat waves. Animals experiencing severe heat stress show panting, reduced movement, pile-up behavior (seeking shade and contact), and in extreme cases prostration and death. Intensive confinement systems are particularly problematic during heat events - animals cannot seek shade, move to cooler areas, or access adequate water. During the 2022 European heat wave, hundreds of thousands of farmed animals died in heat-related mortality events. These mass deaths represent both individual welfare tragedies and evidence of systemic failure to plan for predictable climate events. Heat emergency protocols - increased ventilation, additional water stations, reduced stocking density - should be standard requirements, not afterthoughts.

What You Can Do

Support regulations requiring heat emergency plans for livestock facilities
Choose animal products from producers with documented heat management protocols
Advocate for livestock welfare standards that account for climate change projections
Support climate action to reduce the frequency and severity of future heat events
Reduce animal product consumption to lower overall livestock population exposed to heat stress
Support organizations documenting and responding to livestock heat mortality events
Engage with agricultural policy discussions about climate adaptation for farm animal welfare