1.1 This paper deals primarily with the transportation of cattle, pigs, sheep and goats by road, since this covers most of the areas of greatest concern both to veterinarians and to the public; but the long distance transportation of horses to slaughter is also an area of major concern. The transportation of poultry, though it may be the cause of welfare problems, is not specifically covered here.
1.2 Whenever a farmer moves animals from one place to another, some degree of stress is imposed on those animals. Even the simple act of herding animals from one pasture to another on the same farm is often achieved by applying aversive stimuli to the animals – the presence of people, perhaps gesticulating or shouting, the use of sticks or goads, or the use of dogs. The transportation of animals by road usually involves, in addition, disrupting the social grouping of animals, herding them into confined spaces and then making the surface on which they are standing unstable by moving it. Depending on the external climatic conditions, the length of the journey and the design of the vehicle, the animals may also be subjected to ambient temperature and relative humidity which are outside their comfort zone, and deprived of water and food for considerable periods. And at the end of the journey, they will be unloaded into an unfamiliar environment and may need to adapt to yet another social group.
1.3 Although we can demonstrate that the transportation of animals causes them stress – and we can observe confirmatory changes in both behavioural and physiological parameters when animals are stressed by transportation – those parameters neither allow us to quantify the stress experienced by individual animals, nor to compare it reliably with the stress caused by other circumstances. It is difficult to predict or quantify the stress which would be experienced by specific animals in a particular transport situation because of their individual predispositions and the multifactorial nature of the stressors.
1.4 Even if we had comprehensive, generally agreed and objective data which would enable us to predict the levels of stress experienced by all species and classes of livestock during all journey times, at various stocking densities and in all types of vehicles, it would not immediately allow us to draft legislation based on the science. Because we have no baselines or target values for comparison, it would merely lead to debate about what level of stress was acceptable during a particular journey. So it would not directly help us to define journey times, space allowances, rest periods, etc. for all classes of animals; it would merely move the arguments to a different area. To safeguard the welfare of animals during transportation, we therefore need to use a different approach; this paper proposes that we should combine the scientific data we have available with a pragmatic and rational assessment based on the experience of veterinarians working in the field.