| dc.description.abstract | The husbandry and housing of captive American mink (Neogale vison) farmed for their fur have been adapted in recent decades to better facilitate the expression of motivated, species-specific behaviours and promote improved welfare. For example, separate nesting areas with bedding are provided to allow for privacy and warmth at whelping (wild mink will nest in underground dens), and one manipulable environmental enrichment is now required in each pen to prevent abnormal behaviours and negative affective states like boredom (mink are skilled hunters and do not have the opportunity to chase or chew ‘prey’ in captivity). These interventions have been somewhat successful in improving mink health, welfare, and productivity, but issues such as stereotypic behaviour (SB) and kit mortality remain widespread. In the present study, two early-life enrichment strategies were implemented in captive mink and their relative effects on various measures of welfare were compared to that of a standard-housed group. Enrichment at whelping (EW; dams provided with extra, high-quality nest building materials prior to whelping) was predicted to positively impact nest environments, dam behaviour, and dam welfare in the peri-whelping period, indirectly conferring long-term benefits for kit stress responsiveness; it has been demonstrated in other species that maternal welfare can influence the quality of maternal care delivered to offspring, which in turn modulates offspring stress response development and behaviour. Enrichment once kits were mobile (EK; kits provided with extra physical enrichment items from 3-15 weeks post-whelping) was predicted to benefit kits directly through increased behavioural opportunities in the juvenile phase, a critical period for the prevention of SB. Our results demonstrated that EW housing positively affected several behavioural indicators of dam welfare in the peri-whelping period (e.g., SB), facilitated improvements in nest structure, and resulted in a trend towards decreased kit mortality compared to other treatments; however, dams’ basal faecal cortisol and kit-directed maternal care behaviours were not affected. EW kits also did not exhibit the expected faecal cortisol response to a stressor, and spleen weights of EW kits as adults (an indicator of chronic stress) did not differ from those of other treatments. EK housing significantly increased kits’ enrichment use compared to EW and standard-housed kits in the juvenile period, however, this enrichment strategy did not appear to confer long-term protective effects for the development of SB in EK kits as adults. Kit behaviour and temperament were also largely unaffected by EK housing, aside from a positive effect towards reduced inactivity in the nest box (a potential indicator of fear) and a negative effect towards increased lying awake (a potential indicator of boredom) in the late juvenile period. Interestingly, EW kits also exhibited increased social play compared to EK kits in this period. Overall, we conclude that the EW enrichment strategy was relatively more beneficial for mink, emphasizing the role of the perinatal environment in modulating kit development and facilitating the expression of motivated behaviours in dams. The EK intervention was effective at increasing enrichment use, which may have practical applications for enrichment provision in farmed mink; however, critical periods of enrichment provision for the prevention of SB in mink should be further investigated. | en_US |
