Laboratory mouse aggression study

Aggression in group-housed mice is a serious welfare concern. Mice are used extensively for the purposes of scientific research, with over 2.7 million mice being used in the UK in 2017 alone [1]. Further understanding of the factors influencing mouse aggression could have a significant positive welfare impact on a large number of animals.

The NC3Rs led a crowdsourcing data project to collect data on the prevalence of and potential triggers for aggression in group-housed, male laboratory mice. In total, 44 facilities from nine countries participated in the study and data was collected by 143 animal technicians. A total of 788 incidents of aggression-related injuries were reported across a sample population of 137,580 mice.

For further information, please email mouseaggressionstudy@nc3rs.org.uk.

How technicians participated in the study:

• Technicians observed group-housed male mice during daily routine cage checks and recorded information on incidents of aggression.
• Technicians claimed ten hours of Continual Professional Development (CPD) credits from the Institute of Animal Technology.
• Participants were invited to view a video tutorial that provided background information on the aims of the study, together with step-by-step instructions on how to collect and submit data. A written version of the instructions is given here. A summary of answers to frequently asked questions is given here.
• Data was collected over a consecutive four-week period between 1 September and 30 November 2017 and recorded using an Excel spreadsheet. 
• The data was submitted to the NC3Rs, anonymised, checked and queries cleared with participants. It has now been analysed and is currently being prepared for publication in a peer-reviewed journal.

Background reading

Reviews/summaries

1. Bussell J, Wells SE (2015). Talking welfare: the importance of a common language. Mamm Genome 26: 482-485. doi: 10.1007/s00335-015-9591-x
2. Charles River (2012). Reducing aggression in mice. Technical sheet. http://www.criver.com/files/pdfs/rms/c57bl6/rm_rm_r_reducing_aggression_in-_mice_tech.aspx (accessed 29 August 2017).
3. Gaskill BN (2014). Aggression in laboratory mice: potential influences and how to manage it. The Enrichment Record Winter 2014: 22-25. https://www.research.uky.edu/uploads/aggression-lab-mice (accessed 29 August 2017).
4. Hurst JL (2005). Making sense of scents: reducing aggression and uncontrolled variation in laboratory mice. NC3Rs invited article. https://www.nc3rs.org.uk/sites/default/files/documents/NC3RsarticleJaneHurst%20making%20sense%20of%20scents.pdf (accessed 29 August 2017).
5. Weber EM et al. (2017). Aggression in group-housed laboratory mice: why can't we solve the problem? Lab Animal 46: 157-161. doi: 10.1038/laban.1219
6. Van Loo PLP et al. (2003). Male management: coping with aggression problems in male mice. Lab Animal 37: 300-313. doi: 10.1258/002367703322389870

Research papers

1. Annas A et al. (2013). Group housing of male CD1 mice: reflections from toxicity studies. Lab Animals 47: 127-129. doi: 10.1177/0023677213476278
2. Gaskill BN, Prichett-Corning KR (2015). The effect of cage space on behaviour and reproduction in Crl:CD1(Icr) and C57BL/6NCrl laboratory mice. PLoS One 10: e0127875. doi: 10.1371/journal.pone.0127875
3. Gaskill BN et al. (2017). The effect of early life experience, environment, and genetic factors on spontaneous home-cage aggression-related wounding in male C57BL/6 mice. Lab Animal 46: 176-184. doi: 10.1038/laban.1225
4. Lockworth CR et al. (2015). Effect of enrichment devices on aggression in manipulated nude mice. Journal of the American Association for Laboratory Animal Science 54: 731-736. PMCID: PMC4671788

References