Sandgrav Bak, A., Malmkvist, J. 2020. Barren housing and negative handling decrease the exploratory approach in farmed mink. Applied Animal Behaviour Science 222, 104901.
We examined the influence of cage enrichment and different types of short-term experiences on the temperament of farmed mink. We used juvenile Palomino mink (n = 600, housed in pairs of one male and one female) in a two-factor design with cage environment (BAR: barren vs. ENR: cage enriched with a shelf and a tube throughout) and exposure to one type of short-term experience (Negative: caught and kept in a small trapping cage for 15 min, Neutral: no treatment, and Positive: provision of canned cat food treat). The test-naïve mink were evaluated for curiosity and fearfulness in a voluntary approach-avoidance test (stick test) in their home cage after 4 weeks of housing treatment (BAR vs. ENR) on the day following the short-term experience. Both the housing and the type of short-term experience, with no interaction between them, influenced the proportion of mink scored explorative in the first stick test. Mink in the ENR cages were more curious, as they had a shorter latency to exploratory contact (P < 0.001), and a larger proportion were scored explorative (30.1 %) than mink housed in BAR cages (17.4 %; P < 0.001). The type of short-term experience affected females, but not males. Female mink exposed to the negative event were scored less explorative and kept a longer distance (42 ±2.5 cm) during the test than did mink exposed to no (31 ±2.4 cm) or the positive (28 ±2.1 cm) event (P < 0.001). We re-tested all mink 3 weeks later, after the grading of the winter fur, which is a handling procedure conducted yearly during the late part of the production year on commercial farms. The distance to the stick increased on average 27 % after this fur grading procedure. BAR mink were more sensitive than ENR mink, as they increased the distance more after the fur grading procedure (BAR: 12 ±1.2 cm vs. ENR: 5 ±1.7 cm, P < 0.001). Further, the BAR mink shifted towards a more fearful temperament score than ENR mink after the fur grading procedure. In conclusion, exposure to a negative handling experience increased avoidance and reduced the number of exploratory female mink. Thereby, negative handling and cage bareness pose a risk for increasing the proportion of fearful mink on farms. In contrast, relatively simple cage enrichments to mink may increase on-farm welfare via a shift from fearfulness towards more curiosity.