Article

Behavioral Effects of Cage Size and Environmental Enrichment in New Zealand White Rabbits

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Abstract

One of the goals of environmental enrichment is to encourage species-typical behaviors, while discouraging abnormal behaviors or stereotypies. Assessing the effectiveness of various enrichment modalities can be challenging, particularly for prey species such as rabbits that exhibit freezing responses in the presence of people. In this study, we housed rabbits in 3 different sized cages and observed their behaviors. The 3 cage sizes were our standard rabbit housing cage, a medium sized cage, and a large run. Based on analysis of the recordings, ethograms were constructed and behaviors were quantified. The rabbits in large runs spent more time performing active, exploratory behaviors (431 ± 74 s) than rabbits in the standard cages(184 ± 55 s). However, space constraints inside research facilities often make it impractical to house rabbits in large runs.Therefore, we decided to explore if enrichment devices could promote the expression of active behaviors, similar to those displayed by rabbits housed in the large runs. We selected 3 devices: a hanging toy, a destructible device, and a dig bin. All 3 enrichment devices promoted more time spent performing active, exploratory behaviors (389 ± 48, 463 ± 50, and 420 ± 44 s,respectively), compared with control rabbits housed without an enrichment device (226 ± 53 s). We also analyzed the fecal glucocorticoids of rabbits after shipping or surgery to determine if enrichment devices could mitigate the physiologic impact of these stressors. We found no significant differences in fecal glucocorticoid levels between rabbits that experienced the stressor and rabbits that did not, or between rabbits with or without enrichment devices. Overall, the provision of largercaging and/or addition of enrichment devices encouraged a broad spectrum of active, species-typical rabbit behaviors, suggestiveof improved animal welfare.

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... floor size 3.84 m 2 ). The rabbit ethogram (Table 1) was adapted from previous publications on NZW rabbits' behavior in cages and pens [6,15,16]. The behavioral analyses were conducted on a daily basis at the same time points (7:30 a.m., 9:30 a.m., 11:30 a.m., and 12:30 p.m.) by the same observer. ...
... This might be an indication that social stress affects animals and prevents them from resting for longer periods of time. It has been reported that self-grooming increases after size restriction, while explorative behavior increases with enclosure size for NZW rabbits [15]. We demonstrate that the time animals spent exploring the enclosure drops in parallel to the number of exploratory events in the 3-pen trial compared to the 6-pen trial. ...
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