文摘
Usually, farmed silver foxes are housed singly throughout adulthood. Due to the flexible social nature of wild foxes social grouping may act as an alternative housing procedure for adult vixens. However, sociality may involve increased levels of aggression during competition for e.g. dominance with negative impact on foxes’ welfare and future reproduction, in particular for subordinate individuals. In this study we examined consequences of housing adult vixens in triplets for 13 weeks from September to December on their body weight development, occurrence of wounds and future reproduction. To evaluate effects of social competition dominance relations were recorded. Three-hundred-and-fifty-eight one to four year old silver fox vixens housed in six different commercial farms participated in the study. In each farm half of the vixens were housed in single cages as controls whereas the other half were housed in triplets in three connected cages consisting of one one-year-old, one two-year-old and one three- or four-year-old vixen. After the triplets were separated in December all animals were housed singly until they were mated in February and throughout the breeding period. Socially housed vixens gained more weight compared to the singly housed controls during the group housing period, however, the lowest ranked vixen were significantly lighter (7.0 ± 0.11 kg) compared to the second ranked vixens (7.4 ± 0.11 kg), indicating possible food competition. Yet, the body weight of subordinate vixens was not below that of singly housed controls (6.9 ± 0.05 kg) at the end of the group housing period. Thirty-six % of the group housed vixens had scabs or injuries 3 weeks following the start of the experiment whereas this was 2.3 % in the controls. 1.7 % (N = 6) of the group housed vixens were excluded from the experiment due to infectious bite wounds. Damaging aggression seemed to decrease with succeeding time as 6.7 % of the group housed vixens had injuries at the end of the experiment. There were no effects of social housing on the vixens reproductive output apart from heat development that occurred on average two days earlier in group housed vixens. Dominant vixens weaned approximately one more cub (4.3 ± 0.33) compared to the lower ranked vixens (3.2 ± 0.34, P = 0.036). To conclude, aggression during social housing in autumn may jeopardize foxes’ welfare and have negative consequences for future reproduction in subordinate vixens. Future studies are needed to clarify how various housing procedures affect social dynamics in group housed foxes.
