Various adap- tation options
are available for housing systems to provide cli-
mate ameliora- tion for broilers, with ventilation being one of the most important considerations.
Understanding heat stress Heat stress sets in on broiler farms when the ambient tem- perature exceeds 25°C while high relative humidity could also alter broilers’ perception of the heat. The concept of heat stress or exposure to high ambient temperatures can be broadly categorised into acute and chronic heat stress. Acute heat stress refers to exposure to stress due to a very high temperature for a short period of time with the main effect on broilers being an increase in mortality, often due to suffocation. Chronic heat stress refers to exposure to a high temperature for a prolonged period of several weeks which results in reduced weight gain, decreased production, dimin- ished reproduction and reduced growth performance, as well as compromised broiler welfare.
Adaptation options Broiler housing systems must provide an adequate pen temperature and relative humidity, plus optimum air cir- culation. In closed housing systems the temperature and humidity are fully controlled using foggers, tunnel ventila- tors, fans and misting pumps. In addition, the orientation and sophistication of housing units, walls, flooring and roofing types for broiler housing should be considered to minimise the adverse effects of an elevated environmental temperature. Orientation of the housing units should allow for cross-ventilation. Low-walled structures with wire mesh ensures cross-ventilation while high-walled structures keep the heat inside. Moreover, mud wall houses provide
12 ▶ POULTRY WORLD | No. 2, 2022
a cooler interior than brick wall housing units. The roofing style should provide proper ventilation with materials that enable heat transfer. The type of floor has also been reported to influence broiler temperature, for example, a wire mesh floor decreases skin temperature and cloacal temperature, as well as the respiratory and heart rate of broilers compared to a deep litter floor during the hot season. There may be a point too, where evaporative cooling pads are not efficient enough to cool broilers. Therefore, other innovative solutions may be required, such as using air conditioning units and increasing the insulation level of barns. However, there is an optimum level of insulation which depends on the location and weather patterns. In conclusion, climate change may lead to a reduction in the energy demand for heating and an increase in the energy and water required for cooling in broiler houses. Various adaptation options are available for housing systems to pro- vide climate amelioration for broilers. However, only limited work has been done to understand the impact of climate change on broiler production, reproduction, growth perfor- mance, health and welfare. These effects could create new risks for the sustainability of broiler production by changing the resource requirement for temperature control in broiler houses. Further research to gain a better understanding of these factors should be conducted by government agencies and NGOs on climate change mitigation and adaptation, as well as resilience strategies, to minimise the adverse effects of climate change.
PHOTO: ANNE VAN DER WOUDE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36
