Effect of family housing of farmed silver foxes (<i>Vulpes vulpes</i>) in outdoor enclosures on some behavioural and physiological parameters

Abstract

Group housing of silver foxes in large housing systems has been claimed to promote the welfare of the species since it provides foxes with the possibility to express species-specific social and locomotor behaviour. In our study, silver foxes were housed in outdoor enclosures in family units consisting of a vixen and her four cubs. Foxes housed alone in traditional fox cages were used as control animals. Light hour activity, rectal temperature during human handling and restraint, activity of the HPA axis, heart and gastrocnemius muscle mass, succinate-dehydrogenase activity in gastrocnemius muscle and mechanical properties of tibia were determined from the foxes. The effect of different housing systems was more pronounced in the cubs than in the vixens, indicating the importance of earlier experiences on animals' performance. Both the increased rectal temperature and the increased activity of the HPA axis especially in the cubs housed in enclosures show that the foxes housed in enclosures had a greater fear level towards man than the foxes housed in cages. Furthermore, the foxes, especially the male cubs, raised in groups may have experienced stress due to social tension. Although the exercise-related parameters may indicate that a larger available space could be beneficial for the foxes' physical endurance, these parameters had no clear correlation with physiological welfare parameters. Key words: Behaviour, fear, physical endurance, HPA axis, stress-induced hyperthermia, Vulpes vulpes