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Welfare assessment

General principles for welfare assessments.


The term ‘welfare assessment’ applies not only to monitoring animals for signs of pain, suffering and distress associated with procedures, but also to the routine assessment of all animals to check for any health or welfare problems. Recognising signs of suffering is essential to taking early action and refining humane endpoints. It is also important to recognise and promote positive/good welfare; for example when evaluating the effects of refinement techniques such as environmental enrichment. Welfare assessment is a component of the scientific method, because physiological and psychological responses to suffering can significantly affect data quality. Finally, the legal requirement to report ‘actual severity’ under the Animals (Scientific Procedures) Act 1986, amended 2012 and Directive 2010/63/EU also requires accurate recognition and assessment of suffering.

Appropriate indicators of suffering and wellbeing should be identified for each species, strain (if appropriate) and procedure, and practical protocols to recognise and record these indicators should be established. A ‘team’ approach, incorporating the expertise of researchers, veterinarians, animal technologists and care staff, will help to ensure that effective welfare assessment protocols are set up, reviewed and revised when necessary, and clearly understood by all those responsible for monitoring animals. Local ethical or animal care and use committees, such as the UK Animal Welfare and Ethical Review Body (AWERB), will also have an interest in welfare assessment.

Identifying welfare indicators

The European Commission Working document on a severity assessment framework sets out guidance on selecting appropriate indicators of welfare, including a glossary of indicators that can be tailored to individual species.  There are six ‘high level’ categories:

  • Appearance, including body, coat and skin condition; for example unkempt coat, porphyrin staining
  • Body functions, such as reduced food intake, changes in body temperature
  • Environment within the enclosure; for example, nest quality, consistency of faeces
  • Behaviours, including social interaction, posture, gait, and undesirable behaviours such as stereotypies
  • Procedure-specific indicators, for example, tumour size in cancer studies
  • Free observations, for observers to enter their own text should they see an indicator of suffering that was not predicted

When defining suitable indicators for each procedure, a good starting point is to consider the whole procedure, identifying different types and sources of suffering that may occur. This includes anxiety and distress as well as physical pain, and the effects of handling, restraint, any husbandry restrictions and humane killing, in addition to direct effects of scientific procedures.

An ideal list of indicators should combine objective criteria, such as body weight, with subjective indicators, such as coat condition, posture or social behaviour. It should also include parameters such as reduced nest quality, which can allow early indicators of poor welfare to be detected, rather than overly focusing on indicators of more significant suffering, like piloerection. The number of indicators should be sufficient to reliably detect signs of suffering, and observable within a timeframe that also allows adequate free assessment of the animal by a competent observer. A ‘free text’ box within a welfare assessment score sheet will enable additional observations to be recorded.

The timing and frequency of observations should take account of the animals’ normal activity patterns, timing of scientific procedures and likely levels of suffering. For example, rats and mice are nocturnal, so important behavioural indicators will probably be missed if observations are restricted to the light phase (human working day) when the animals should be asleep. Similarly, assessment should be more frequent at times when adverse events are more likely, such as in the post-surgical period or at critical times during disease studies. 

Assessing and reporting actual severity

In the UK, the Guidance to the Operation of the Animals (Scientific Procedures) Act 1986 states that a suitably qualified person must classify the actual severity of each procedure as ‘non-recovery’, ‘mild’, ‘moderate’, or ‘severe’, after the procedure has ended. The basis for the classification is a review of the day-to-day (cage-side) records of welfare assessments – not the prospective severity, or the type of procedure – so the actual and prospective severity classifications may differ. More guidance can be found within the European Commission severity assessment document and examples.

Effective record keeping and review

Record keeping systems, either electronic or on paper, are essential for effective day-to-day welfare monitoring and for project review.  Records should be set up so that observations of welfare problems are readily apparent, information is provided that will support the project review, and actual severity assessments can readily be extracted and reported. It is also good practice to review welfare assessment records at appropriate intervals, to ensure that suffering was effectively predicted for the ongoing study, that the most suitable indicators are being used consistently by all, and that suffering is being adequately recognised and dealt with.

It is worthwhile to periodically take an overview of welfare assessment protocols at the research institution. This should help to ensure that there are no problem areas, and that protocols are operating effectively and taking account of new approaches and developments, such as the use of grimace scales to assess pain following surgical procedures. Input from, or discussion with, relevant local bodies such as the AWERB should also be useful with respect to review at a project and/or establishment level.


Effective welfare assessment depends upon a team of staff who between them possess the necessary knowledge and practical skills. To achieve competence, training should be tailored to the species, projects and welfare assessment processes of each individual research institution. A report of the Joint Working Group on Refinement includes guidance on the requisite competencies and suggested training topics, and tutorials with training materials can be found on the AHWLA website.



  1. Joint Working Group on Refinement (2011) A guide to defining and implementing protocols for the welfare assessment of laboratory animals Lab Anim 45 (1): 1-13. 
  2. ILAR, DELS, National Research Council (2008) Recognition and alleviation of distress in laboratory animals, The National Academies Press.
  3. ILAR, DELS, National Research Council (2009) Recognition and alleviation of pain in laboratory animals, The National Academies Press. 
  4. Wells DJ, Playle LC, Enser WEJ et al. (2006) Assessing the welfare of genetically altered miceLab Anim. 40: 111.
Information provided by Penny Hawkins, RSPCA.