Effect of temperament and behavioural reactions to the presence of a human during the pre-mating period on reproductive performance in farmed mink (Mustela vison)

The present study sought to evaluate the relationship between temperament, pre-mating behaviour and reproductive performance in farmed female mink (Mustela vison). Temperament was measured by using a stick test and behavioural reactions to the presence of a human during pre-mating period by a walking test. The experimental animals comprised 100 confident and 100 fearful scanblack female mink. In each temperament group, 58% of female mink were primiparous and 42% were multiparous. The length and timing of mating periods and the length of the gestation period were similar in all groups. Pooled data showed that the length of the gestation period correlated negatively with litter size (r = -0.17, P = 0.03). The whelping proportions for confident and fearful primiparous female mink were 81% and 74% (P = 0.37), respectively, and for multiparous females 83% and 81% (P = 0.78), respectively. The number of kits per mated and whelped female at parturition (P < 0.01 and P = 0.04, respectively) and at weaning (P < 0.01 and P = 0.07, respectively) was significantly higher in confident than in fearful females. A significant correlation between kit losses and litter size was found only in primiparous and multiparous confident females (r = 0.35, P = 0.02; r = 0.32, P = 0.07). Postnatal kit mortality was higher in primiparous confident females than fearful females. During walking tests, fearful animals, irrespective of age, remained inside the nest box more frequently than did confident ones. Stationary behaviour outside the cage (lying, sitting, standing, etc.) was more common in confident than in fearful animals (P < 0.001). Significant differences in locomotor activity or stereotypies were not found between the groups. In multiparous fearful females, the whelping result declined significantly with the increasing incidence of stereotypies (r = -0.37, P = 0.04). In primiparous fearful female mink, the relationship was the reverse (r = 0.37; P = 0.01). We conclude that the significant temperament dichotomy (confident vs. fearful) found in farmed mink stock has a marked effect on the reproductive performance of this species.