Effects of family housing on behaviour, plasma cortisol and performance inadult female mink (Mustela vison)

Various behavioural, physiological and production-related parameters were e xamined in 200 adult female pastel and pearl mink either family housed in t hree-room cages with no weaning or housed singly in one-room cages after no rmal weaning procedures. Scanning observations of behaviour and use of the cages were performed in the nursing period and several parameters related t o reproduction were registered. The adult female mink were weighed when kit s were 16 weeks old (September) and again at pelting time (November). Blood samples were collected from all adult female mink in September at which ti me the teat condition and fur damage were evaluated. After pelting, bite ma rks on the leather side of the skin were counted, fur damage was graded aft er severity and the fur size was measured. Some positive consequences of be ing family housed were revealed. The family-housed adult female mink showed a lower level of stereotypes and a higher level of defensiveness and curio sity than the adult female mink in one-room cages during the nursing period . In September and November, family-housed adult females were heavier than singly housed adult females. However, most of the physiological or producti on-related parameters pointed in a negative direction for family-housed adu lt female mink, Reproductive success was somewhat reduced, although not sig nificantly. Plasma cortisol levels were elevated in September, indicating h igher levels of stress in these females. They showed a generally poor teat condition in September, with a high proportion of swollen or bitten teats. A high proportion of these adult females showed fur damage in both Septembe r and November, and a high number of bite marks was found on the leather si de of the skins of these females, indicating that family housing had a high cost for the adult female mink. In conclusion, there seem to be some benef its, at least on the behavioural level, in keeping adult female mink in thr ee-room cages during the nursing period, but both physiological and product ion-related parameters indicated that the welfare of the adult female mink was threatened if she was continuously co-housed with her litter past the n ormal age of weaning.