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An overview on setting protocols for assessing the welfare of laboratory animals.
The effective assessment of pain, suffering, and distress in laboratory animals is a highly topical issue at present1, largely because it is a vital step towards achieving the goal of reducing animal suffering. The ability to detect signs of pain or distress as rapidly as possible means that appropriate action may be taken to alleviate that suffering sooner, ideally decreasing both its intensity and duration.
Reducing suffering and improving welfare is also widely recognised to be an important component of good science, as well as being essential for humane reasons. This is reflected in the new European Directive 2010/63 that regulates the care and use of experimental animals, which explicitly requires that the three R’s of replacement, reduction, and refinement are implemented, and emphasises the need to eliminate or minimise any possible pain, suffering, distress, or lasting harm2,3.
However, there is more to refinement than minimising—and preferably avoiding—suffering. Increasing consideration is being given to improving welfare and encouraging positive mental states in experimental animals, with the aim of providing a good quality of life. For this reason, the term “welfare assessment” is used in this article to encompass the concept of assessing both negative and positive states of well-being.
THE STORY SO FAR
So, what is the current state of affairs with respect to welfare assessment? Considerable progress has been made in recent years, both in the ability to detect more subtle indicators of discomfort and pain, and in the recognition that animals can experience negative psychological states such as anxiety and distress, which can and should be minimised.
For example, guidance on recognising pain and distress in rodents published in 1996 includes a number of clinical signs that would be taken to indicate moderate to severe suffering today, such as hunched posture, piloerection, laboured respiration, vocalisation (presumably audible), and self-mutilation4. More recent publications include much longer lists of indicators of both pain and distress, with examples of more subtle behavioural signs. For instance, changes in fecal pellet production, stiff movements, reduced alertness, or reduced nest-building behavior can indicate milder levels of suffering that can be acted upon in good time.
Newer publications also highlight the use of very specific, subtle, and previously unrecognised (or undocumented) indicators such as “flank twitching” in rats post-laparotomy5,6. Some of these signs are relatively easy to identify and assess and they have undoubtedly contributed towards the prevention and alleviation of animal suffering5,6. Despite such progress, however, the current situation is far from perfect with respect to welfare assessment. On the plus side, there is greater awareness that behavioural indicators of suffering can be subtle, more thought is given to encouraging and assessing positive mental states in animals, and there are increased efforts to be objective, including the use of tools such as “score sheets”. However, there remains much of reliance on subjective judgements and relatively gross indicators are still used, such as hunching in rodents and vocalisation. Additionally, it takes time to assess animals properly, and not all establishments allow for this7.