Full title: Opinion of the FRCAW on thermal comfort, thermal stress factors and mitigating actions during the transport of pigs
Requested by: Animal Welfare Office (BBEA) of the General Directorate for Food (DGAL), French Ministry of Agriculture and Food Sovereignty
Date delivered by the FRCAW: 28/02/2025
Date of publication in English: 09/12/2025
DOI: 10.17180/ds9e-ep26
Context
The European regulations on the welfare of farm animals are currently being revised. In December 2023, the European Commission published its Proposal for a Regulation of the European Parliament and of the Council on the protection of animals during transport and related operations, amending Regulation (EC) No 1255/97 and abrogating Regulation (EC) No 1/2005 currently in force. This revision is intended to update regulatory requirements in light of the latest scientific advances on animal welfare during transport, and is based on expert opinions published by the European Food Safety Authority (EFSA) at the request of the European Commission. The draft revision of Regulation 1/2005 proposes forecast external temperature limits that must be respected when deciding whether or not to authorise the transport of live animals of all species and breeds and in all locations. Negotiations between the Member States are ongoing (first semester of 2025).
To support its arguments during the European discussions, the Animal Welfare Office of the DGAL requested that the FRCAW answer the following questions: i) "What are the thermoneutral zones for pigs?", ii) "What parameters […] can be used to regulate the temperatures perceived by animals during transport?" and iii) "How can these parameters be modified to improve the thermal comfort of the animals?".
The FRCAW’s report summarises the key points contained in the EFSA opinion on the welfare of pigs during transport, focusing exclusively on information on thermal stress during road transport.
It examines three areas:
- Physiological and behavioral mechanisms of temperature regulation in pigs exposed to high and low temperatures
- Endogenous and exogenous factors that may induce thermal stress in pigs during road transport
- Levers for action in the event of high or low temperatures to improve the thermal comfort of pigs during the different transport stages: loading and unloading, transport in the lorry, and journey breaks
Main conclusions of the FRCAW
- When the weather forecast for all or part of a journey would prevent pigs from remaining within their thermoneutral zone (TNZ) while inside a vehicle, the decision should be taken for animals not to travel in order to reduce their risk of thermal stress.
- The EFSA does not specify a journey duration threshold below which it would be allowable to transport animals under sub-optimal conditions. Therefore, regardless of the journey duration, no pig should be transported when temperatures in the lorry are likely to be above the upper critical temperature (set at 22-25°C for sows, 25-27°C for finishing pigs and 30°C for weaners) or below the lower critical temperature (18°C for sows, 22°C for finishing pigs and 24°C for weaners). In hot weather, it is therefore preferable to arrange for journeys to be made early in the morning or during the night.
- With regard to low temperatures, the European Commission’s draft regulatory proposal specifies that ‘when the temperature forecast indicates temperatures below 0°C, road vehicles shall be covered and circulation in the animal compartment controlled to protect animals from exposure to windchill during the journey’. At an outside temperature of 0°C, the temperature inside a closed lorry does not exceed 16.9°C, which lies below the lower critical temperature for every category of pig.
- The Thermal Comfort Zone (TCZ) is not as extensive as the TNZ, but it represents the ideal temperature range for the transport of pigs. In the literature, the lower limit of the TCZ is often confused with that of the TNZ. In considering the effect of transport conditions on the welfare of animals, the TCZ should be given priority over the TNZ. For this to happen, though, the limits of the TCZ for pigs need to be better defined, since they have been little studied to date.
- Sensors measuring microclimatic conditions in real time at various points in the lorry should alert the transporter if the TNZ is exceeded during transport, so that the animals can be unloaded at the nearest control post.
- For drivers to be able to carry out the appropriate preventive measures and detect signs of thermal stress in the animals being transported, it is essential that they should be properly trained in good practice and on how to interpret indicators of thermal stress in animals.
- At least three further general measures not addressed in the EFSA Opinion should also be considered in order to significantly reduce the stress placed on animals during transport:
- The slaughter of animals in locations close to their farms of origin would reduce journey times and would facilitate the transport of carcasses rather than live animals.
- Establishing geographical clusters of the various types of production sites (farrowing sows, fatteners) to reduce the time an animal spends being transported across its lifetime.
- Exports of live animals outside the European Union should only be approved if the animals’ welfare is respected in line with the European regulations.
