Colwell D D, Clymer B, Booker C W, Guichon P T, Jim G K, Schunicht O C, Wildman B K
Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta T1J 4B1.
Can Vet J. 2001 Apr;42(4):281-5.
Beef calves from 2 sources entering southern Alberta feedlots in the winters of 1997-98 and 1998-99, were surveyed for the presence of lice. A random sample of multiple source (MS), that is, auction market-derived, calves entering commercial feedlots and single source (SS) calves entering a backgrounding feedlot were examined for the presence of lice at entry to the feedlot. A standardized examination, which involved hair-part examination of 8 louse predilection sites, was conducted on each selected calf to determine prevalence and intensity of infestation. The long-nosed sucking louse, Linognathus vituli, was the most commonly encountered species. This species infested from 57.8% to 95.6% of the calves selected from both MS and SS calves during both winters. Louse index values, indicating intensity of infestation, for L. vituli ranged from 1 to 243 lice per animal. The chewing louse, Bovicola bovis, was present on MS and SS calves only in the winter of 1998-99. The louse index values for B. bovis ranged from 1 to 230 lice per animal. Mixed infestations of the L. vituli and B. bovis were common. The little blue cattle louse, Solenopotes capillatus, was present only on the SS calves in the winter of 1997-98. The short-nosed sucking louse, Haematopinus eurysternus, was present at very low intensities, 1-2 lice per animal, on 2.6% to 4.4% of the MS calves during both winters. Comparison of results from the current study with published literature suggests that efforts to determine the economic impact of louse infestations are confounded by the lack of a uniform method to assess louse population levels.
1997 - 1998年冬季和1998 - 1999年冬季进入艾伯塔省南部饲养场的来自两个来源的肉用犊牛接受了虱子检查。对进入商业饲养场的多源（MS）犊牛（即来自拍卖市场的犊牛）和进入育肥前期饲养场的单源（SS）犊牛的随机样本在进入饲养场时进行了虱子检查。对每头选定的犊牛进行了标准化检查，包括对8个虱子偏好部位进行毛发分开检查，以确定感染率和感染强度。长鼻吸血虱，即牛血虱，是最常见的种类。在这两个冬季，从MS和SS犊牛中挑选的犊牛中，该种类的感染率为57.8%至95.6%。牛血虱的虱子指数值（表明感染强度）为每头动物1至243只虱子。咀嚼虱，即牛虱，仅在1998 - 1999年冬季出现在MS和SS犊牛身上。牛虱的虱子指数值为每头动物1至230只虱子。牛血虱和牛虱的混合感染很常见。小蓝牛虱，即毛细血虱，仅在1997 - 1998年冬季出现在SS犊牛身上。短鼻吸血虱，即宽额血虱，在这两个冬季，在2.6%至4.4%的MS犊牛身上出现的强度非常低，每头动物1 - 2只虱子。将本研究结果与已发表文献进行比较表明，由于缺乏评估虱子种群水平的统一方法，确定虱子感染经济影响的努力受到了混淆。
