The assessment of animal welfare with the help of score sheets

Laboratory animals are often subjected to stressful and sometimes painful procedures. Ensuring the well-being of these animals is of great importance from both a legal and ethical perspective. According to the existing EU directive, all animals must be examined by a competent person at least once a day and appropriate measures must be taken in case of illness or injury. Increasing welfare and acting according to the principles of replacement, reduction and refinement (3Rs) represent the central principles in animal experimentation.¹

In order to assess the health status of the animals as objectively and transparently as possible, score sheets can be used. Score sheets are protocols that serve to record the clinical status and well-being of the test animals. It is important that these are adapted to the particular experiment and therefore, apart from general parameters such as activity or behavior, also include model-specific criteria. Thus, the adaptation of the score sheet to the animal species used and to the planned experiment is a basic requirement to be able to assess the actual health status. For example, in an arthritis model, special consideration must be given to factors such as swelling or redness of the joints and lameness, whereas in a tumor model where metastases could occur, attention must be paid to respiration, leukocyte counts, or other biomarkers. Similarly, the frequency of the examination must be adapted to the experiment. For example, clinical status must be collected much more often immediately after a surgical procedures.²

Apart from maximizing the refinement, the score sheet is also a suitable means to classify the severity of a stress and thus to provide for possible intervention at the appropriate time. Depending on the case, it can be decided whether and which therapeutic measures have to be taken, or even whether an early termination of the experiment has to take place for the individual animal in terms of a humane endpoint.³

In order to design a useful score sheet, consideration must first be given to which parameters are appropriate to collect the most comprehensive as well as accurate picture of the animal's clinical status. Next, a decision must be made as to which scoring system should be used. In principle, a distinction is made between a binary (yes/no or present/absent) and a numerical scoring system for the evaluation of symptoms. Finally, it has to be considered from which score on which measures have to be taken to guarantee the well-being of the animals and a high quality of the experiment.⁴

Even if the design, implementation of the assessment, and evaluation of the collected findings represent a certain time commitment, the implementation of a score sheet should be ensured for the purpose of animal welfare as well as to guarantee good and reproducible research. It is also essential that the experience gained and the results obtained are shared with the scientific community.⁵

Example Score Sheets:

• Fentener van Vlissingen JM, Borrens M, Girod A, Lelovas P, Morrison F, Torres YS. The reporting of clinical signs in laboratory animals: FELASA Working Group Report. Lab Anim. 2015 Oct;49(4):267-83. doi: 10.1177/0023677215584249. Epub 2015 May 8. PMID: 25957286.
• Kanzler S, Rix A, Czigany Z, Tanaka H, Fukushima K, Kögel B, Tolba RH. Recommendation for severity assessment following liver resection and liver transplantation in rats: Part I. Lab Anim. 2016, 50(6), 459-467.
• Palle P, Ferreira FM, Methner A, Buch T. The more the merrier? Scoring, statistics and animal welfare in experimental autoimmune encephalomyelitis. Lab Anim. 2016 Dec;50(6):427-432. doi: 10.1177/0023677216675008. PMID: 27909192.
• Pinkernell S, Becker K, Lindauer U. Severity assessment and scoring for neurosurgical models in rodents. Lab Anim. 2016;50(6):442-452. doi:10.1177/0023677216675010
• A Pilot Study of Postoperative Animal Welfare as a Guidance Tool in the Development of a Kidney Autotransplantation Model with Extended Warm Ischemia - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Animal-welfare-score-sheet-used-at-the-animal-facilities-at-Department-of-Clinical_tbl1_336380401 [accessed 16 May, 2023]
• Lohmann S, Eijken M, Møldrup U, Møller BK, Hunter J, Moers C, Ploeg RJ, Baan CC, Jespersen B, Keller AK. A Pilot Study of Postoperative Animal Welfare as a Guidance Tool in the Development of a Kidney Autotransplantation Model with Extended Warm Ischemia. Transplant Direct. 2019 Oct 8;5(11):e495. doi: 10.1097/TXD.0000000000000941. PMID: 31773049; PMCID: PMC6831118.

Sources: 
1) Bugnon P, Heimann M, Thallmair M. What the literature tells us about score sheet design. Lab Anim. 2016 Dec;50(6):414-417. doi: 10.1177/0023677216671552. PMID: 27909190. RL 2010/63/EU
2) Bugnon P, Heimann M, Thallmair M. What the literature tells us about score sheet design. Lab Anim. 2016 Dec;50(6):414-417. doi: 10.1177/0023677216671552. PMID: 27909190. Golledge H, Jirkof P. Score sheets and analgesia. Lab Anim. 2016 Dec;50(6):411-413. doi: 10.1177/0023677216675387. PMID: 27909189. Guidelines for use and application of a score sheet. Research Ethics and Integrity Animal Ethics, University of Queensland (Australia). 2022 Feb.
3) Dülsner A, Greweling-Pils M, Hack R, Kürger C, Manthey T, Paulin N, Scherer K, Schmelting B, Schmidt M, Siegeler K, Weinert H, Wißmann A. Möglichkeiten der Belastungsbeurteilung im Tierversuch, GV Solas. 2020 Feb
4) Bugnon P, Heimann M, Thallmair M. What the literature tells us about score sheet design. Lab Anim. 2016 Dec;50(6):414-417. doi: 10.1177/0023677216671552. PMID: 27909190.
5) van der Meer M, Rolls A, Baumans V, Olivier B, van Zutphen LF. Use of score sheets for welfare assessment of transgenic mice. Lab Anim. 2001 Oct;35(4):379-89. doi: 10.1258/0023677011911859. PMID: 11669323. Golledge H, Jirkof P. Score sheets and analgesia. Lab Anim. 2016 Dec;50(6):411-413. doi: 10.1177/0023677216675387. PMID: 27909189.