Mitchell M A, Kettlewell P J
Roslin Institute (Edinburgh), Midlothian, United Kingdom.
Poult Sci. 1998 Dec;77(12):1803-14. doi: 10.1093/ps/77.12.1803.
The rearing of large numbers of broiler chickens at geographically dispersed sites means that they have to be transported by road, over various distances, to centralized processing plants for slaughter. The birds may be exposed to a variety of stressors during transit, including the thermal demands of the transport microenvironment. The thermal environments experienced by broiler chickens during routine transport in the U.K. on a large number of commercial vehicles under a wide range of external climatic conditions have been characterized using three-dimensional thermal mapping (temperature and water vapor density). Inadequate ventilation results in heterogeneous distributions of temperature and humidity and, thus, thermal loads within the vehicle, and, therefore, the existence of a "thermal core" in which the risk of heat stress is increased. Relationships between specific physiological indices of stress and quantified thermal loads have been determined in accurate transport simulations in the laboratory. The findings have been employed to establish a predictive model of the induction of heat stress during commercial transportation, as well as to define the acceptable ranges and limits for temperature and humidity within the transport containers. These principles have been utilized in developing a monitoring system to warn of impending heat stress and in improving vehicle design to facilitate the prevention of heat stress during broiler transportation.
在地理上分散的地点饲养大量肉鸡，这意味着它们必须通过公路运输，历经不同距离，送往集中的加工厂进行屠宰。在运输过程中，鸡只可能会受到各种应激源的影响，包括运输微环境的热需求。利用三维热成像（温度和水汽密度）对英国大量商用车辆在广泛的外部气候条件下进行常规运输时肉鸡所经历的热环境进行了表征。通风不足会导致车内温度和湿度分布不均，进而导致热负荷不均，因此会存在一个“热核心”，其中热应激风险增加。在实验室精确的运输模拟中确定了特定应激生理指标与量化热负荷之间的关系。这些研究结果已被用于建立商业运输过程中热应激诱导的预测模型，以及确定运输容器内温度和湿度的可接受范围和限度。这些原则已被用于开发一个监测系统，以警告即将发生的热应激，并改进车辆设计，以促进在肉鸡运输过程中预防热应激。
