A safe bet? Inter-laboratory variability in behaviour-based severity assessment

Abstract

Evidence-based severity assessment is essential as a basis for ethical evaluation in animal experimentation to ensure animal welfare, legal compliance and scientific quality. To fulfil these tasks scientists, animal care and veterinary personnel need assessment tools that provide species-relevant measurements of the animals' physical and affective state. In a three-centre study inter-laboratory robustness of body weight monitoring, mouse grimace scale (MGS) and burrowing test were evaluated. The parameters were assessed in naïve and tramadol treated female C57BL/6J mice. During tramadol treatment a body weight loss followed by an increase, when treatment was terminated, was observed in all laboratories. Tramadol treatment did not affect the MGS or burrowing performance. Results were qualitatively comparable between the laboratories, but quantitatively significantly different (inter-laboratory analysis). Burrowing behaviour seems to be highly sensitive to inter-laboratory differences in testing protocol. All locations obtained comparable information regarding the qualitative effect of tramadol treatment in C57BL/6J mice, however, datasets differed as a result of differences in test and housing conditions. In conclusion, our study confirms that results of behavioural testing can be affected by many factors and may differ between laboratories. Nevertheless, the evaluated parameters appeared relatively robust even when conditions were not harmonized extensively and present useful tools for severity assessment. However, analgesia-related side effects on parameters have to be considered carefully.

The Utility of Grimace Scales for Practical Pain Assessment in Laboratory Animals

“…A further important outcome from Miller and Leach [ 58 ] was that there was no effect of repeatedly being placed in the photography boxes on grimace score i.e., a habituation effect over the three occasions used [ 58 ]. The later study by Jirkof et al [ 85 ] in 2020 supports this finding. This provides assurance that longitudinal monitoring post-procedure could occur throughout the day without the need to account for time of day or habituation to the box.…”

“…There is also some evidence of inter-laboratory variation in the outputs obtained from behavioral testing, to include MGS scores. In a multicenter study, Jirkof et al [ 85 ] in 2020 demonstrated some quantitative differences in scores, although they were qualitatively comparable (direction of effect). However, variability between research centers in the MGS, especially when presented as a median score, was less pronounced than in burrowing behavior readouts [ 84 ].…”

The Utility of Grimace Scales for Practical Pain Assessment in Laboratory Animals

“…a habituation effect over the 3 occasions used 58 . The later study by Jirkof et al 85 in 2020 supports this finding. This provides assurance that longitudinal monitoring post-procedure could occur throughout the day without the need to account for time of day or habituation to the box.…”

“…There is also some evidence of inter-laboratory variation in the outputs obtained from behavioural testing, to include MGS scores. In a multicenter study, Jirkof et al 85 in 2020 demonstrated some quantitative differences in scores, although they were qualitatively comparable (direction of effect). However, variability between research centers in the MGS, especially when presented as a median score, was less pronounced than in burrowing behavior readouts 84 .…”

Where are we heading? Challenges in evidence-based severity assessment

“…59 Therefore, again, standardization is crucial as assessment protocols may vary between laboratories, resulting in the lack or changed manifestation of these behaviours (Schwabe et al, this issue; Jirkof et al, this issue). 60,61 Another motivational-or emotionaldriven behaviour, namely voluntary wheel running, has been utilized to assess the severity of experimental procedures. 62 Benefits include an observer-independent, automatized assessment of severity that has been proposed to serve as an indicator of disturbed wellbeing (Mallien et al, this issue).…”