Current Situation
The physiology of heat stress in livestock is well understood. Cattle become heat stressed above 72°F (22°C) combined temperature-humidity index (THI), with severe stress occurring above 80 THI. Pigs have limited sweating capacity and become severely stressed above 25°C. Poultry, particularly high-producing broilers and laying hens, are extremely vulnerable to heat events. Heat stress in broilers causes respiratory distress, reduced feed intake, poor growth, and high mortality. During severe heat events, ventilation failures in poultry barns can kill hundreds of thousands of birds. The 2021 Pacific Northwest heat dome killed millions of farm animals across the US Pacific Northwest and Canada, with records of 36-hour mortality events in inadequately cooled broiler houses. Cooling technologies have been developed and deployed in intensive systems. Evaporative cooling systems in poultry houses, sprinkler and soaker systems for pigs and cattle, and shade structures for pasture cattle can significantly reduce heat stress. However, these technologies require capital investment and energy, creating cost barriers for smaller producers and those in developing countries. Feed management strategies can help mitigate heat stress impacts. Shifting feeding times to cooler periods, increasing nutrient density to compensate for reduced intake, adding electrolytes to water, and using feed additives including antioxidants and yeast products can improve heat tolerance. Genetic selection for heat tolerance is a long-term adaptation strategy. Research programs in tropical cattle breeds, including Bos indicus crosses, have identified genomic markers for heat tolerance. The introduction of the slick gene from Senepol cattle has improved heat tolerance in dairy breeds. Outdoor and pasture-based systems require shade provision as a fundamental welfare measure. Access to shade significantly reduces cortisol levels and improves reproductive performance in heat-stressed cattle.
Key Welfare Issues
The intersection of poverty, cultural practices, enforcement capacity, and international demand drives wildlife welfare outcomes. Addressing root causes—including consumer demand reduction, alternative livelihood programs, and strengthened legal frameworks—is essential for lasting improvement.
Conservation and Welfare Intersection
Wildlife conservation and animal welfare increasingly converge as researchers recognize that conservation outcomes improve when individual animal welfare is considered alongside population-level metrics. Humane wildlife management benefits both individual animals and species recovery programs.
Pathways Forward
Progress requires coordinated action across governments, NGOs, local communities, and international organizations. Demand reduction campaigns, community-based conservation, improved enforcement, and sanctuaries for rescued animals all play important roles in improving wildlife welfare outcomes.
Resources
Organizations including TRAFFIC, Free the Bears, Animals Asia, and WWF provide resources and support conservation and welfare programs in the region.