Providing elevated ‘getaway bunks’ to nursing mink dams improves their health and welfare
Publication Type: |
Journal Article |
Year of Publication: |
2013 |
Authors: |
Lauren Dawson, Misha Buob, Derek Haley, Steve Miller, Judy Stryker, Margaret Quinton, Georgia Mason |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
bunks, mastitis, mink, nursing, nursing sickness, welfare |
ISBN: |
01681591 |
Abstract:
Farmed mink infants (Neovison vison) remain with their mothers beyond natural weaning age. This benefits their welfare, but can stress their mothers and contribute to illness (e.g. ‘nursing sickness’). European studies have explored augmenting cages with structures allowing mothers to get away from their infants (‘kits’); these show that if provided with high, shelf-like structures permitting rest away from kits, dams utilise them. Here, we assessed the benefits of providing an elevated ‘getaway bunk’ – a wire-mesh half-cylinder attached to the cage ceiling – to 80 Black dams on an Ontario farm. Controls comprised nursing females without bunks (n = 80), and barren females given bunks (n = 40). Behaviour was observed daily over kit ages 23–42 days. Mothers were removed from litters at 42 days (typical for North American farms), at which time health and production parameters were recorded. Mothers used bunks approximately half as much as barren dams, but their bunk-use increased as kits aged, up to c. 7% scans (c. 30 min per observation day). Seasonal changes in temperature did not explain this pattern. Bunks increased maternal rest (from 78.9 to 82.3% of scans; c. 16 min per observation day), and increased the time spent with teats inaccessible to kits by a similar amount. Dams with bunks showed approximately one third less stereotypy (3.7% scans, compared to 5.4% in bunkless controls): a reduction most evident when kits were aged 30–42 days, when infants transition from milk to water and solid food; and, although apparently not protected from nursing sickness, at the end of lactation they were less likely to have swollen, red and/or crusty teats (which thermal imaging also showed were significantly hotter), suggesting less mastitis. Such benefits seemed particularly strong in multiparous dams: effects of bunks on teat health and stereotypy as a proportion of activity (not scans) were significant in older dams but not first-time mothers when analysed separately. Kits’ suckling opportunities and time spent nursing were not significantly reduced by the bunks, however; nor did bunks compromise kit survivorship or weights at 42 days. Elevated bunks can thus enhance mink mothers’ welfare during the nursing period, seemingly without serious drawbacks for their kits. Unexpectedly, however, all study dams had very high mortality (>20%; more than triple that of non-experimental animals on the farm), suggesting that repeated live observation, or being housed close to barren dams, may elevate risks of nursing sickness.