Kok D J, Fourie L J, Loomes M D, Oberem P T
Department of Zoology and Entomology, University of the Orange Free State, Bloemfontein, South Africa.
Vet Parasitol. 1996 May;63(1-2):109-17. doi: 10.1016/0304-4017(95)00886-1.
Synthetic pyrethroid pour-on compounds have been developed for use on cattle but many are now also registered for the control of ectoparasites on small ruminants. The breed of small livestock has been known to influence the efficacy of various pour-ons and we hypothesized that differences in the duration of protection afforded by a synthetic pyrethroid pour-on against ticks on small livestock, would be greatest between hairy and woolly breeds. Angora goats with mohair, Dorper sheep with hairy wool, and Merino sheep with wool were treated with 1% m/v deltamethrin pour-on with an oil base at a dosage rate of 1 ml 5 kg-1 body mass. The duration of effective protection against Ixodes rubicundus, the Karoo paralysis tick, was determined under field conditions. Angora goats proved to be the highest risk group, but were afforded the least protection. Efficacy never reached 100% in this group and within 3 weeks the goats were already at risk of paralysis. Dorper sheep were afforded above 90% protection for 3 weeks and 85% after 4 weeks. In the case of the Merino sheep efficacy of protection remained above 90% up to 7 weeks post-treatment and was still 87% during Week 8. Differences in the amount of sebum and suint in the epidermis of the different breeds may be responsible for differences in the rate of spread and the rate of dilution of the active compound in the epidermis.
合成拟除虫菊酯浇泼剂化合物已开发用于牛，但现在许多也已注册用于控制小型反刍动物的体外寄生虫。已知小型家畜的品种会影响各种浇泼剂的功效，我们推测，合成拟除虫菊酯浇泼剂对小型家畜蜱虫的保护持续时间差异，在有毛品种和羊毛品种之间最为显著。用1%（质量/体积）含油基的溴氰菊酯浇泼剂以1毫升/5千克体重的剂量率对安哥拉山羊（有马海毛）、杜泊羊（有毛羊毛）和美利奴羊（有羊毛）进行处理。在田间条件下测定了对红硬蜱（卡鲁麻痹蜱）的有效保护持续时间。结果表明，安哥拉山羊是风险最高的群体，但得到的保护最少。该组的功效从未达到100%，在3周内山羊就已面临麻痹风险。杜泊羊在3周内得到了90%以上的保护，4周后为85%。对于美利奴羊，保护功效在处理后7周内保持在90%以上，第8周时仍为87%。不同品种表皮中皮脂和羊汗量的差异可能是活性化合物在表皮中的扩散速率和稀释速率存在差异的原因。
