Alva-Valdes R, Wallace D H, Egerton J R, Benz G W, Gross S J, Wooden J W, Reuter V E
Animal Science Research, Merck Sharp & Dohme Research Laboratories, Rahway, NJ 07065.
Am J Vet Res. 1988 Oct;49(10):1726-8.
Twelve Holstein calves were used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-1 calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P less than 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was greater than 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).
选用12头荷斯坦犊牛来确定伊维菌素对胃肠道和肺线虫攻击感染的预防效果。根据体重通过受限随机化将其分为两组，每组6头犊牛（平均体重205千克）。第1组犊牛作为未用药对照组。第2组的每头犊牛口服一粒原型缓释大丸剂，设计为以每日8毫克的持续剂量释放伊维菌素。在治疗后第28天和第42天给犊牛接种第三期线虫感染性幼虫。治疗后77或78天对犊牛实施安乐死。伊维菌素在预防感染性血矛线虫、奥氏奥斯特线虫、古柏属线虫（点状古柏线虫、康氏古柏线虫、苏氏古柏线虫）、瑞士细颈线虫、辐射食道口线虫和胎生网尾线虫方面的有效率为100%（P<0.05），对艾氏毛圆线虫的有效率大于99%。毛首线虫属的偶然感染减少了94%（P = 0.08）。
