Impact of climate change on broiler housing systems

By 2050, global meat consumption is expected to reach 455 million tonnes per year in response to expected population growth and dietary shifts towards higher protein foods. Broiler production is an important part of the global meat market and the broiler industry is expected to meet approximately 40% of the increased universal demand for meat. Increasing and maintaining food production at this level will lead to increased energy consumption.

Climate change has an impact on the resources needed for production

Conversely, there is growing concern about the impact of climate change on broiler production given that it has been predicted that by 2100 the average temperature will increase by 2-6°C, this which poses a serious challenge to sustainable broiler production. Climate change will further influence the type and sophistication of broiler housing systems and alter the resource requirements for broiler production. The economic and productive efficiency of broilers is related to housing systems and climatic conditions. It is therefore essential to adapt broiler housing systems to current and projected climate change in order to minimize its adverse effects on the broiler industry.

Effects of climate change

Climate change is defined as long-term deviations in weather patterns and temperature. Rising global temperatures, as well as desert encroachment and deforestation associated with climate change, will add to the burden of heat stress experienced, particularly in tropical regions and during summer. Heat stress promotes behavioral, physiological and biochemical changes in broilers, leading to economic losses. Additionally, it will result in decreased water availability and increased cooling energy required, thereby potentially compromising broiler production, reproduction, growth performance, health and welfare. .

Control the microclimate

Running barns at full capacity with uniformly sized flocks of birds is a common practice, which allows more precise control of the microclimate inside the barn and improves efficiency. Industrial broiler production involves controlling the indoor microclimate driven by heat fluxes occurring inside the barn and the demands of broilers throughout their growth stages.

Heating, ventilation and air conditioning systems are used to control the temperature in the poultry house. In winter, mechanical ventilation is used to circulate air and remove accumulated gases. In summer, ventilation and different forms of active cooling are used to keep the indoor temperature below a certain threshold. Evaporative cooling pads are the most common method of active cooling used when temperatures exceed 30°C for periods longer than 2-3 hours.

Regulation of body temperature

Broilers have a limited ability to respond to temperature changes due to the lack of sweat glands. They can tolerate a narrow temperature range of 18-24°C in their thermoneutral zone. In the thermoneutral zone, the broiler’s body temperature is kept constant and the bird loses heat at a controlled rate without discomfort. Heat stress in broilers results in mortality or reduced weight gain, decreased production, decreased reproduction and reduced growth performance, and compromised welfare. When ambient temperatures are high, broilers must regulate their body temperature by panting, resting, drinking water and reducing physical activity to balance heat production versus heat loss and maintain relatively constant body temperature.

Understanding heat stress

Heat stress sets in in broiler flocks when the ambient temperature exceeds 25°C, while high relative humidity can also alter broilers’ perception of heat. The concept of heat stress or exposure to high ambient temperatures can be broadly categorized into acute and chronic heat stress. Acute heat stress refers to exposure to stress due to very high temperature for a short period of time, with the main effect on broilers being increased mortality, often due to suffocation. Chronic heat stress refers to exposure to high temperature for a prolonged period of several weeks, which results in reduced body weight gain, decreased production, decreased reproduction, and reduced growth performance, as well as compromised broiler welfare.

Adaptation possibilities

Broiler housing systems must provide adequate temperature and relative humidity, as well as optimal air circulation. In closed housing systems, temperature and humidity are fully controlled using foggers, tunnel fans, fans and misting pumps.

Additionally, the orientation and sophistication of types of housing units, walls, flooring and roofing for broiler housing should be considered to minimize the adverse effects of an ambient temperature. high:

  • Ventilation: The orientation of the dwellings must allow cross ventilation. Low-walled structures with wire mesh provide cross-ventilation while high-walled structures retain heat inside.
  • Walls: In addition, mud wall houses offer a cooler interior than brick-walled dwelling units.
  • Type of roof: Must provide adequate ventilation with materials that allow heat transfer.
  • Floor: It has also been reported that the type of floor influences the temperature of broilers, for example, a wire mesh floor decreases the skin temperature and cloacal temperature, as well as the respiratory and heart rate of broilers compared to a heavily littered floor during the hot season.
  • Insulation: There may also be a point where evaporative cooling pads are not effective enough to cool broilers. Therefore, other innovative solutions may be needed, such as using air conditioning units and increasing the level of insulation in barns. However, there is an optimal level of insulation that depends on location and weather conditions.

Final remarks

In conclusion, climate change can lead to a reduction in energy demand for heating and an increase in the energy and water needed to cool poultry houses. Various adaptation options are available for housing systems to improve the broiler climate. However, only limited work has been done to understand the impact of climate change on broiler production, reproduction, growth performance, health and welfare.

These effects could create new risks to the sustainability of broiler production by altering the resource requirements for temperature control in poultry houses. Further research to better understand these factors should be conducted by government agencies and NGOs on climate change mitigation and adaptation, as well as resilience strategies, to minimize the adverse effects of climate change.

Teresa H. Sadler