Ethics of Research involving animals
Sources of harm for laboratory animals
4.31 The discussion about pain, suffering and distress that research animals may experience is often focused on experimental procedures. Respondents to the Consultation also pointed out that: ‘It is not only scientific procedures that can cause suffering to animals, but also the conditions of their captivity. Many laboratory animals are kept in bare, sterile living conditions…’
The Dr Hadwen Trust for Humane Research
‘Environmental factors…have a great impact on the laboratory animal throughout its entire life, not only during experiments.’
Professor Vera Baumans
Animals may experience adverse physiological and psychological states that can result from a range of factors (Box 4.4). We now give systematic consideration to a number of areas that influence an animal’s welfare independent of, or in addition to, specific experimental procedures. These include:
- breeding (including the use of wild-caught animals);t
- transportation;
- housing;
- husbandry and
care; - handling;
- restraint;
- identification;
- any adverse effects of the procedures (e.g. nausea from toxic compounds, discomfort and pain from induced syndromes, natural and experimental infections); and
- euthanasia.
As this list demonstrates, the full lifetime experience of animals involved in research must be carefully considered and given due weight to permit an adequate evaluation of the harms or ‘costs’ that are likely to arise. Such evaluations always need to be specific to the context. As will be clear from the discussions in Chapters 5–9, animal research takes a wide range of forms and the implications for welfare depend significantly on the type of research. There is also variation in two other important factors. First, although there are a number of codes of practice that set out minimum standards, for example for the size of cages (see paragraph 13.10), facilities often vary with regard to providing conditions above the minimum standards. Secondly, whether or not animals will experience pain and suffering also depends critically on the skills and motivation of those handling them to implement Refinements, such as the use of pain relieving medicines or the provision of enrichments (see Chapter 12). We therefore do not attempt to describe the full range of welfare implications that all animals will necessarily experience when used in research. Rather, we aim to provide a systematic description of the types of effects that animals may experience, depending on the circumstances in which they are used.28 Many of these effects can be lessened considerably by best practice in animal care and welfare, and responsible scientists and animal technicians will seek to reduce them as far as possible.
| Box 4.4: Adverse physiological and psychological states Animals can experience both physiological and psychological adverse states. These are intimately linked and dependent upon one another, as the physiological and behavioural response to stress affects a number of biological functions and systems. For example, animals housed at artificially low temperatures will be under physiological stress as they expend energy to maintain their core body temperature by huddling together, shivering and reducing the blood supply to the skin. If such stress is extreme or prolonged, substantial effort will be required to maintain a state of equilibrium. The animals may become aware of this effort and suffer as a result. Alternatively, a social animal housed individually in a barren cage at an appropriate temperature, relative humidity and light level may not be under any immediate physiological stress but will probably experience psychological stress due to boredom and anxiety. This can lead to physiological changes such as alterations in heart rate and body temperature, and disturbed sleep patterns.* * Späni D, Arras M, König B and Rülicke T (2003) Higher heart rate of laboratory mice housed individually vs in pairs Lab Anim 37: 54–62 |
Breeding/Use of wild-caught animals/Transport
4.32 The process of breeding animals for laboratory use can involve the thwarting of many natural behaviours. Most significantly, laboratory animals are usually weaned and separated from their mothers at a time convenient for research purposes, which rarely coincides with the time when they would have dispersed naturally. It is sometimes argued that this is not a problem since some animals ‘drive’ their offspring away in any case. However, in many species, the separation is not total and permanent; the young join the extended colony and kin relationships are maintained. Early weaning can thus be stressful for both the juvenile animals and their mothers.29 This feature is increasingly recognised in primates, and it also needs to be considered in the case of other animals that care for their young.
4.33 Another important aspect of breeding concerns the possibility of wastage of newborn animals which are euthanised because they are surplus to requirements. Such wastage can sometimes arise if there is lack of communication and forward planning, or if only one sex is required. Care also needs to be taken that standards of housing and care for breeding animals are of similar quality to those which should be provided for research animals.
Use of wild-caught animals
4.34 Most laboratory animals are bred specifically for the purpose, but some are caught from the wild, especially for use in basic biological research. For example, some wild birds are caught for physiological studies; many Xenopus frogs are caught in the wild and some countries still use wild-caught primates (although not the UK) or obtain captive-bred primates from breeders who replenish their breeding stock with animals captured from the wild. In the UK, the use of wild-caught primates is prohibited except where exceptional and specific justification can be established (see paragraph 4.26).
4.35 Capture from the wild imposes significant psychological stress on animals that are not habituated to humans or to captivity. It usually presents a number of risks to the animal and can result in physical injury, shock or even death. In addition to the impact on the target animal, effects on other animals also need to be considered as they may experience stress leading to behavioural disturbances that could leave them open to predation or cause them to abandon their young. This could affect not only other members of the colony in social species, but also animals of other species that are disturbed during the capture process.30
Transport
4.36 Transport is a significant life event for laboratory animals and it may involve a number of aversive and stressful elements.31 Studies of animal transport have focused primarily on farm rather than laboratory animals.32 It has been hypothesised that stressful conditions could affect both the welfare of laboratory animals and the scientific validity of any future studies involving the animals or their offspring. The precise effect of transport varies depending on transit time, the species involved and a number of more detailed circumstances. The implications of transportation over short distances, such as moving mice within a building, as well as that over longer distances, as in the case of the import of macaques from their country of origin to the UK, which can take up to 60 hours, need to be considered.33 Adverse effects from transport can result from factors that include the following:
- handling (see paragraphs 4.44–4.47);
- separation from familiar animals;
- housing changes;
- confinement in an unfamiliar transport container;
- loading and unloading, movement and vibrations during the journey, including
- acceleration and
deceleration; - physical stress due to maintaining balance (especially for larger animals);
- unfamiliar sights, sounds and smells;
- fluctuations in temperature and humidity;
- availability of food and drinking water; and
- disruption of light/dark regimes and possibly adaptation to a different time zone.
Stress during longer journeys may also increase the risk of disease for transported animals. The potential to monitor animal well-being, and to act if it is compromised, is often significantly curtailed during such transport next page
28 Further information on adverse effects and on ways of preventing or alleviating them can be found in a series of reports by
the BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement, which cover husbandry and care; the administration of
substances and GM mice.
29 Kanari K, Kikusui T, Takeuchi Y and Mori Y (2005) Multidimensional structure of anxiety-related behavior in early-weaned rats
Behav Brain Res 156: 45–52.
30 Implications of any authorised release to the wild also need to be considered. The A(SP)A states that ‘Where a project licence
authorises the setting free of a protected animal in the course of a series of regulated procedures, that licence shall include a
condition requiring the prior consent of the Secretary of State to the setting free of the animal.’ See A(SP)A Section 10 (3B).
31 See Swallow J, Anderson D, Buckwell AC et al. (2005) Report of the Transport Working Group established by the LASA:
Guidance on the transport of laboratory animals Lab anim 39: 1–39.
32 See Grandin T (1997) Assessment of Stress During Handling and Transport J Anim Sci 75: 249–57.
33 See Tuli JS, Smith JA and Morton DB (1995) Stress measurements in mice after transportation Lab Anim 29: 132–8.