Norwegian Veterinary Institute, Department of Animal Health, Welfare and Food Safety, PO Box 750 Sentrum, N-0106 Oslo, Norway.
Norwegian Institute for Nature Research, PO Box 5685 Torgard, NO-7485 Trondheim, Norway.
J Wildl Dis. 2020 Jul;56(3):687-692. doi: 10.7589/2019-07-185. Epub 2020 Mar 20.
The deer ked (), a hematophagous ectoparasite of cervids, is currently spreading in Scandinavia, and the moose () is its main host. However, little is known about the impact of deer keds on moose. We analyzed the hair cortisol concentration (HCC) from 262 moose harvested in the fall in relation to age class, sex, body mass (BM), and deer ked infestation intensity, and BM in relation to age class, sex, and infestation intensity. We found that HCC decreased with increasing deer ked intensity at low ked intensities, but for the higher levels of ked intensities, there was a positive relationship between HCC and ked intensity. The HCC was higher in males than in females and lower in yearlings than in calves and adults. Our failure to find any association between BM and deer ked intensity suggested a negligible impact of deer ked infestation on moose foraging and metabolism at the level of infestation observed early in the infestation, but did not exclude an effect later in winter. Our findings suggested that moose generally tolerated moderate parasitism by keds. However, the increase in HCC at higher ked intensities suggested that the tolerance strategy could be disrupted with further increases in intensities and consequently may negatively affect animal health and welfare.
鹿虻（），一种吸血的鹿科寄生虫，目前正在斯堪的纳维亚传播，驼鹿（）是其主要宿主。然而，人们对鹿虻对驼鹿的影响知之甚少。我们分析了 262 头秋季收获的驼鹿的毛发皮质醇浓度（HCC）与年龄组、性别、体重（BM）和鹿虻寄生强度的关系，以及 BM 与年龄组、性别和寄生强度的关系。我们发现，在低鹿虻强度下，HCC 随着鹿虻强度的增加而降低，但在更高的鹿虻强度下，HCC 与鹿虻强度之间呈正相关。雄性的 HCC 高于雌性，幼鹿的 HCC 低于小牛和成年鹿。我们没有发现 BM 与鹿虻强度之间存在任何关联，这表明在寄生早期观察到的寄生水平上，鹿虻的寄生对驼鹿的觅食和新陈代谢几乎没有影响，但不排除在冬季后期的影响。我们的研究结果表明，驼鹿通常可以耐受中等程度的虻寄生。然而，在更高的鹿虻强度下 HCC 的增加表明，随着强度的进一步增加，耐受策略可能会被打破，从而可能对动物的健康和福利产生负面影响。
