Decreased litter size in inactive female mink (Neovison vison): Mediating variables and implications for overall productivity

作者：Meagher Rebecca^*; Bechard Allison; Palme Rupert; Diez Leon Maria; Hunter Douglas Bruce; Mason Georgia

来源：Canadian Journal of Animal Science, 2012, 92(2): 131-141.

DOI：10.4141/CJAS2011-107

• American mink
• Neovison vison
• inactivity
• reproductive success
• stress
• body condition

Meagher, R., Bechard, A., Palme, R., Diez-Leon, M., Hunter, D. B. and Mason, G. 2012. Decreased litter size in inactive female mink (Neovison vison): Mediating variables and implications for overall productivity. Can J. Anim. Sci. 92: 131-141. Farmed mink vary dramatically in activity: very inactive individuals rarely leave the nest-box, while others spend hours active daily, often performing stereotypic behaviour (SB). SB typically correlates with increased reproductive output, and inactivity, with decreased output. Our objectives were to determine whether SB or inactivity best predicted litter size (LS), and to test three hypothesized reasons for inactive dams%26apos; reduced LS: HI, excess fat; H2, chronic stress (potentially underlying inactivity because fear motivates hiding); and H3, health problems. We assessed time budgets pre-breeding, scored body condition visually, conducted health exams, and assessed stress using faecal cortisol metabolites (FCM) and %26quot;glove tests%26quot; for fear. Results did not support H2 and H3: inactive females were no more fearful than active females (P%26gt;0.10), they excreted lower levels of FCM (P=0.033), and were considered healthy. As predicted by HI, inactive females had higher body condition scores (P%26lt;0.0001), which predicted decreased LS (P=0.040). However, path analysis determined this was unlikely to mediate the inactivity LS relationship. Compared with SB, inactivity more consistently predicted both LS (negatively, P%26lt;0.038) and kit weight (positively, P%26lt;0.037). Therefore, decreasing inactivity in farmed mink, rather than increasing their SB or decreasing their body condition should most improve productivity.

• 出版日期2012-6