Lohmeyer K H, Miller J A, Pound J M, Klavons J A
USDA-ARS, Knipling Bushland U.S. Livestock Insect Research Laboratory, 2700 Fredericksburg Road, Kerrville, TX 78028, USA.
J Econ Entomol. 2009 Apr;102(2):804-8. doi: 10.1603/029.102.0243.
A gel formulation formed by incorporating technical doramectin into a 10% hydroxypropyl methylcellulose aqueous solution was used to subcutaneously inject steers at varying dosages. Doramectin serum concentration of steers receiving 600 microg (AI)/kg body weight declined from 21.9 ppb at 0.5 wk to below detectable at 8 wk postinjection. The 1,200 microg (AI)/kg injection resulted in serum concentrations of 29.1 ppb at 0.5 wk and declined to 0.5 ppb at 8 wk postinjection. Both the 600 and 1,200 microg (AI)/kg injections provided 100% inhibition of index of fecundity (IF) in adult lone star ticks, Amblyomma americanum L. (Acari: Ixodidae) through week 8, after which inhibition declined to 79.4 and 45.3%, respectively, during the 12th week posttreatment. For steers treated at 600 microg (AI)/kg, mortality of adult horn flies, Hematobia irritans L. (Diptera: Muscidae), declined from 16.9% during week 2 to 3.1% during week 7 postinjection. The blood from steers treated at 1,200 microg (AI)/kg resulted in a similar decline in mortality of blood fed adult horn flies from 29.4% during week 1 to 4.0% during week 7. The 600 microg (AI)/kg treatment provided complete control of larval horn flies in the manure for 9 wk, whereas the 1,200 microg (AI)/kg injection gave complete control for 14 wk posttreatment. The doramectin gel formulation provided long-lasting delivery of doramectin to cattle and extended control of lone star ticks and larval horn flies. Such a simple and inexpensive formulation could be useful in tick eradication programs by reducing the frequency of gathering cattle.
将技术级多拉菌素加入10%羟丙基甲基纤维素水溶液中形成的凝胶制剂，被用于以不同剂量皮下注射阉牛。接受600微克（活性成分）/千克体重注射的阉牛，其多拉菌素血清浓度在注射后0.5周时为21.9 ppb，到8周时降至检测不到的水平。1200微克（活性成分）/千克的注射剂量在0.5周时导致血清浓度为29.1 ppb，在注射后8周时降至0.5 ppb。600微克（活性成分）/千克和1200微克（活性成分）/千克的注射剂量在第8周前对成年美洲钝眼蜱（美洲花蜱，蜱螨目：硬蜱科）的繁殖力指数（IF）均提供了100%的抑制，之后在治疗后第12周时抑制率分别降至79.4%和45.3%。对于接受600微克（活性成分）/千克治疗的阉牛，成年角蝇（血蝇，双翅目：蝇科）的死亡率从注射后第2周的16.9%降至第7周的3.1%。接受1200微克（活性成分）/千克治疗的阉牛血液导致吸食血液的成年角蝇死亡率出现类似下降，从第1周的29.4%降至第7周的4.0%。600微克（活性成分）/千克的治疗剂量在9周内对粪便中的幼虫角蝇提供了完全控制，而1200微克（活性成分）/千克的注射剂量在治疗后14周内提供了完全控制。多拉菌素凝胶制剂为牛提供了多拉菌素的长效递送，并延长了对美洲钝眼蜱和幼虫角蝇的控制。这种简单且廉价的制剂通过减少聚集牛的频率，可能在蜱虫根除计划中发挥作用。
