AgResearch Limited, The Hopkirk Research Institute, c/o Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand.
Vet Parasitol. 2010 Aug 4;171(3-4):300-4. doi: 10.1016/j.vetpar.2010.03.035. Epub 2010 Apr 2.
To determine the impact of anthelmintic resistance on the productivity of sheep grazed on pasture in a temperate climatic zone, 14 groups each of 20 lambs were grazed on pasture on which benzimidazole-resistant parasites had been detected previously, then treated every 28 days - seven groups with a benzimidazole anthelmintic (albendazole) and seven with monepantel, a member of a new anthelmintic action family which was assumed in advance to be completely effective in removing all established worms. Faecal egg counts and larval differentiation demonstrated the presence of albendazole resistance, predominantly in Teladorsagia circumcincta but also in Trichostrongylus spp. By days 84 and 112, egg counts were significantly higher in the albendazole-treated animals than in those treated with monepantel. The presence of anthelmintic resistance resulted in a reduction in live-weight of 2.8 kg, a significant increase in breech-soiling and a significant reduction in body condition score. Fourteen animals from each treatment were necropsied at a commercial abattoir and carcase weights and standard quality parameters recorded; there was a reduction in carcase weight of 2.8 kg in the albendazole-treated animals, and a difference in the carcase grades within each group. These measurements were used to calculate that the presence of anthelmintic resistance resulted in a 14% reduction in carcase value.
为了确定抗蠕虫药物耐药性对在温带气候区放牧绵羊生产力的影响，14 组每组 20 只羔羊在先前检测到存在苯并咪唑耐药寄生虫的牧场上放牧，然后每隔 28 天用苯并咪唑驱虫药（阿苯达唑）和莫能菌素（一种假定能完全有效去除所有已建立的蠕虫的新型驱虫作用家族成员）治疗七组。粪便虫卵计数和幼虫分化表明存在阿苯达唑耐药性，主要存在于泰乐菌素circumcincta 中，但也存在于 Trichostrongylus spp. 中。到第 84 天和第 112 天，用阿苯达唑治疗的动物的卵计数明显高于用莫能菌素治疗的动物。抗蠕虫药物耐药性的存在导致活体重减轻 2.8 公斤，臀部污染显著增加，身体状况评分显著降低。每个治疗组的 14 只动物在商业屠宰场进行剖检，并记录胴体重和标准质量参数；用阿苯达唑治疗的动物的胴体重减轻了 2.8 公斤，每个组内的胴体等级也存在差异。这些测量结果用于计算出抗蠕虫药物耐药性的存在导致胴体价值降低了 14%。
