Tail Tip Lesions in Mink (Neovison vison): Effects of an Additional Hammock in Multilevel Cages

Summary: There are several animal welfare concerns in farmed mink, including the occurrence of wounds, such as tail tip lesions. However, little is known about how these lesions develop. An increasing tendency to develop tail tip wounds was reported by Norwegian mink farmers after the introduction of multilevel cages. It appears that the mink jump directly at a presumably high speed from the upper level towards the nest box on ground level, causing the tail to hit the wire mesh several times. This study investigates whether cage design may be involved in the development of tail tip lesions. Specifically, effects of installing an additional hammock in standard multilevel cages, intended to reduce speed during transitions between cage levels and thereby assumed to lower the incidence and severity of tails hitting the wire mesh, were investigated in 600 mink at three farms (300 with hammocks and 300 without hammocks). More tail tip lesions were found in mink housed in cages without a hammock. Further studies are needed to understand the causal relationship between cage design and tail tip lesions in mink, in order to develop recommendations for improved cage designs and thereby improving animal welfare.