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Nesting material enrichment reduces severity of overgrooming-related self-injury in individually housed rats


Nesting material enrichment reduces severity of overgrooming-related self-injury in individually housed rats

Khoo, Shaun Yon-Seng ORCID: https://orcid.org/0000-0002-0972-3788, Correia, Vanessa and Uhrig, Alexandra (2020) Nesting material enrichment reduces severity of overgrooming-related self-injury in individually housed rats. Laboratory Animals . ISSN 0023-6772

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Official URL: https://doi.org/10.1177/0023677219894356


Individual or singly-housing laboratory rats is common in many animal facilities, but has an adverse impact on the welfare of this social species. It has previously been shown that a small proportion of individually housed mice (∼5%) engage in pathological overgrooming behaviour, but this has not been assessed in rats. We performed an observational study to determine the prevalence of overgrooming-related self-injury and whether providing nesting material enrichment throughout an animal’s life would affect the prevalence or severity of overgrooming-related self-injury. Due to protocol differences between projects in our behavioural neuroscience lab, unenriched rats received a nylabone and a shelter (n = 167), while baseline-enriched rats received a nylabone, shelter and shredded paper nesting material throughout experiments (n = 238). Unenriched rats received nesting material enrichment after the onset of overgrooming-related self-injury. Over 18 months, rats were monitored by their experimenters on a daily basis (5–7 days/week over 2–3 months/project) and any cases of overgrooming-related self-injury were recorded. Replicating the findings of previous studies in mice, we observed 20 cases of overgrooming-related self-injury (∼5%) with no difference in prevalence between rats on the basis of supplier, cage position, experimental procedure (behavioural only or involving surgical procedures), reinforcer (ethanol or sugar) or level of baseline-enrichment. While there was no difference in onset severity between rats that were unenriched at baseline and baseline-enriched rats, baseline-enriched rats had lower self-injury severity scores at one-, two- and four-week follow-ups. These results suggest that nesting material enrichment provided throughout an animal’s life may reduce overgrooming-related self-injury.

Divisions:Concordia University > Research Units > Centre for Studies in Behavioural Neurobiology
Item Type:Article
Authors:Khoo, Shaun Yon-Seng and Correia, Vanessa and Uhrig, Alexandra
Journal or Publication:Laboratory Animals
Date:10 January 2020
  • Canadian Institutes of Health Research
  • Natural Sciences and Engineering Research Council
  • Fonds de Recherche du Québec - Santé
  • Concordia University
Digital Object Identifier (DOI):10.1177/0023677219894356
Keywords:Grooming, Nesting, Social Behaviour, Housing, Refinement
ID Code:986113
Deposited On:15 Jan 2020 15:48
Last Modified:15 Jan 2020 18:09
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