Phillips F E, Logan N B, Jones R M
Pfizer Central Research, Grnton, CI 06340, USA.
Am J Vet Res. 1996 Oct;57(10):1468-71.
To evaluate the safety and efficacy of doramectin given by injection at a dosage of 200 micrograms/kg of body weight for treatment of gastrointestinal nematodiasis or louse infestations of cattle.
1,031 mixed-breed cattle were treated in the nematode study and 418 were treated in the louse study.
Naturally parasitized cattle were given 200 micrograms of doramectin/kg or an equivalent volume of saline solution, SC. In nematode experiments, fecal samples were collected from each animal 1 week before treatment, at time of treatment, and at weekly intervals there after for 3 weeks. In louse experiments, louse counts were carried out for each animal on the day of treatment and 14 and 28 days later. All cattle were weighted at the time of treatment and at the end of the experiment.
By 21 days after doramectin treatment, fecal egg counts had decreased to zero in 9 of 10 experiments and to 1 egg/g in the remaining experiment. Differences between treatment groups were significant (P < 0.0001) in all instances. Pretreatment coproculture identified Haemonchus, Ostertagia, Cooperia, Trichostrongylus, and Nematrodirus as the represented genera. Doramectin was 100% effective in eliminating infestation with Linogna thus vituli, Haematopinus eurysternus, and Solenopotes capillatus. Infestation with the chewing louse Damalinia bovis was reduced overall by 86%. For all species, post treatment louse counts were significantly (P < 0.02) less for doramectin-treated cattle than for controls. Adverse reactions to doramectin were not apparent in either study.
Injectable doramectin at a dosage of 200 micrograms/kg is safe and effective for treatment of gastrointestinal nematodiasis and louse infestations of cattle under field conditions.
评估以200微克/千克体重的剂量注射多拉菌素治疗牛胃肠道线虫病或虱感染的安全性和有效性。
1031头杂种牛参与了线虫研究，418头参与了虱研究。
对自然感染寄生虫的牛皮下注射200微克多拉菌素/千克或等量的盐溶液。在线虫实验中，在治疗前1周、治疗时以及治疗后每周采集一次每头动物的粪便样本，持续3周。在虱实验中，在治疗当天以及治疗后14天和28天对每头动物进行虱计数。所有牛在治疗时和实验结束时称重。
多拉菌素治疗后21天，在10项实验中有9项粪便虫卵计数降至零，在其余实验中降至1个虫卵/克。所有情况下治疗组之间的差异均具有显著性（P < 0.0001）。治疗前的粪便培养鉴定出感染的属包括血矛线虫属、奥斯特他线虫属、古柏线虫属、毛圆线虫属和细颈线虫属。多拉菌素对消灭牛蜱、牛血虱和毛细虱感染的有效率为100%。对牛嚼虱的总体感染率降低了86%。对于所有物种，多拉菌素治疗的牛治疗后的虱计数显著（P < 0.02）低于对照组。在两项研究中均未观察到对多拉菌素的不良反应。
在田间条件下，以200微克/千克的剂量注射多拉菌素治疗牛胃肠道线虫病和虱感染是安全有效的。
