A note on the reproductive success of primiparous blue fox vixens in social groups.

Our aim was to compare traditional breeding system, i.e. artificial insemination with singly-housing, to alternative breeding systems in farmed blue fox (Alopex lagopus or Vulpes lagopus) vixens. At the age of 7 weeks (i.e. at weaning), 48 randomly selected female blue fox cubs were divided into four experimental groups: (1) artificially inseminated singly-housed vixens in cages (AI-SC), (2) artificially inseminated pair-housed vixens in double-cages (AI-PC), (3) naturally bred pair-housed vixens with a male in triple-cages (NB-PC), and (4) naturally bred pair-housed vixens with a male in outdoor enclosures (NB-PE). The cubs were counted on days 1, 2, 3, 7, 14 and 49 postpartum and the reproductive performance per breeding (RPB) and per mated vixens (RPM) with its subcomponents were formed from these data. RPB was zero in both NB groups. In AI-PC and AI-SC, RPB was 1.3+/-2.5 and 4.1+/-4.7 cubs, respectively. RPB and the percentage of vixens that weaned cubs were lower in NB-PC and NB-PE than in AI-PC. In AI groups, both RPB and RPM at weaning tended to be better in singly-housed than in pair-housed blue fox vixens. No statistically significant differences were found between AI groups in the percentage of vixens without oestrus, barren vixens, vixens that lost all cubs or weaned at least one cub. Only in one pair (AI-PC) both vixens displayed communal breeding and weaned cubs. The present results show that vixens in traditional breeding system had better RPM than in any of the studied pair-housing systems. The current blue fox population has been effectively selected for cage-breeding and artificial reproduction, and therefore blue foxes generally reproduce well with artificial insemination after careful detection of oestrus in traditional breeding conditions.