Additional foraging elements reduce abnormal behaviour – fur-chewing and stereotypic behaviour – in farmed mink (Neovison vison)

• Published in: Applied animal behaviour science Vol. 149; no. 1-4; pp. 77 - 86
• Main Authors: Malmkvist, Jens, Palme, Rupert, Svendsen, Pernille M., Hansen, Steffen W.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2013
• Subjects: adults; body weight; cortisol; diet; farms; females; Foraging; Fur-chewing; juveniles; males; metabolites; mink; Neovison vison; Neovison vison aka Mustela vison; restricted feeding; ropes; stereotyped behavior; Stereotypies; Stress; Welfare; Stereotypies; Welfare; Neovison vison aka Mustela vison; Foraging; Fur-chewing; Stress
• ISSN: 0168-1591; 1872-9045
• DOI: 10.1016/j.applanim.2013.10.001

We investigated whether provision of additional appetitive and consummatory elements of foraging reduces baseline stress and abnormal behaviour – in terms of fur-chewing and stereotypic behaviour – in farmed mink. We studied 200 juveniles (n=100 females and 100 males) during the 5-month growth period with plenty of feed, and subsequently the females as adults during the 2-month feed restriction period before mating. The mink were distributed in four equally sized groups: (i) FARM, conventional finely ground feed (<8mm) without additional foraging elements; (ii) ROPE, access to biting ropes; (iii) CONS, chunky feed (parts up to 42mm), replacing conventional feed; (iv) BOTH, access to both biting ropes and chunky feed. In growing mink, biting ropes reduced fur-chewing (P=0.044) and chunky feed reduced stereotypic behaviour (P=0.038) and fur-chewing in female mink (P=0.019). During the season of feed restriction, the wear/tear of biting ropes increased. Females on the chunky diet had a higher concentration of faecal cortisol metabolites (P=0.033), probably due to a more severe slimming resulting in a 6.2% lower body weight (P=0.006) than the mink on the finely ground diet; still the chunky diet reduced time spent in pre-feeding stereotypies (P=0.001). In the restrictively fed females, fur-chewing was reduced both by access to biting ropes (P=0.005) and chunky feed (P=0.007). Consequently, 54% of group FARM mink displayed fur-chewing compared to 21% in group BOTH. In conclusion, stereotypic behaviour was reduced by provision of chunky feed, increasing the consummatory element in daily foraging. Fur-chewing was reduced upon access to either biting ropes or chunky feed in female mink throughout the study. Our findings support frustrated foraging, mainly consummatory, behind abnormal behaviour.