The EFSA Scientific Panel on Animal Health and Welfare was asked by the Commission to report on the standards for the micro-climate inside animal transport vehicles. Micro-climate on transporters is composed of factors such as temperature and humidity of the air, air velocity, air quality, ventilation and insulation of the surrounding walls, floor, and roof, and can significantly influence welfare and health of the transported animals if not in an appropriate range. Particularly, overheating in summer and too low temperatures in winter can lead to deaths and suffering of the animals from heat or cold stress.
The environmental temperature experienced by the animal depends on interactions within and between environment and animal related parameters. In addition, large regional differences in climate exist in Europe. Conditions which do not cause poor welfare in animals in Northern countries might not be acceptable in Southern countries. Therefore it is necessary to give a sufficiently broad margin of thresholds for temperature and humidity to make the regulation flexible and practicable.
Another problem is that it is very difficult for those responsible of animal transport to quantify the environment on a transport vehicle with living cargo. Therefore, minimal and maximal temperatures were previously fixed to avoid high risk of losses. These are still the target temperatures for the animals, but they may be difficult to implement in specific field conditions. It is however accepted in the literature that some deviations, as defined in the current scientific opinion, may not result in poor welfare; but the unknown factor is to what extent an animal’s adaptation capacity is reduced by handling and transport. It is then difficult to set limits for the duration of any deviation. Some animals may cope easily with the limits defined, while others may suffer, especially depending on journey duration. Hence, journey duration and animal response should be well documented to allow a scientifically based provision of good animal welfare during transport.
The requirements for temperature and ventilation set out in the scientific report adopted by SCAHAW in 1999 on "Standards for the micro-climate inside animal road transport vehicles" (SCAHAW, 1999) remain in general valid in the light of the present scientific knowledge, which is still at a very similar low level with significant gaps as four years ago. However, progress has been made in the understanding of the efficiency of different ventilation systems on transport vehicles such as free ventilation by shutters, sensor controlled side and front vents, and forced ventilation. Taking into account that regional and climatic differences exist and different technological standards apply to the vehicle body in Europe, the present temperature regulation should allow for more flexibility according to the technical equipment of the lorry - such as forced ventilation, misting in summer for cooling purposes, and heating the incoming air in cold condition - until more scientific data are available to establish heat balance models for the different species transported including temperature, relative humidity, air velocity, ventilation rate and air quality. It is important that the climatic condition (temperature, relative humidity, air velocity, heating, misting) inside the trucks can be controlled by the person responsible for the transport. This person must have proper technical training.
As previously explained, the temperature limits will depend on many physiological variables (including adaptation), physical parameters (e.g. air velocity) and operational procedures (e.g. stocking density). In spite of the fact that some of the temperature limits need additional explanation and/or allowance for other physical parameters, it seems possible to draw some conclusions and give recommendations both for actual measures and for future activities.
There is an urgent need for more detailed practical research on micro-climate in transport vehicles in order to develop realistic ventilation models for the different animal species in different climatic zones in Europe based on standardised instrumentation and measuring protocols.