伊维菌素干混悬剂驱除绵羊寄生虫的扩大试验

应用伊维菌素干混悬剂,驱除绵羊体内线虫和体外寄生虫。结果:0.2mg/kg体重剂量对消化道主要线虫及网尾线虫的虫卵(幼虫)转阴率、减少率均为100%,原圆科线虫幼虫转阴率和减少率分别为91.3%、91.8%,对线虫的总计驱虫率98.9%:对绵羊颚虱的杀虫率为100%。结果证明:伊维菌素干混悬剂0.2mg/kg剂量一次用药,驱除绵羊主要线虫和虱等寄生虫,高效安全。     

伊维菌素干混悬剂对羊狂蝇蛆的驱杀效果试验

选择自然感染羊狂蝇蛆绵羊131只,分别按体重0.1,0.2和0.3mg/kg剂量口服伊维菌素干混悬剂,进行驱除效果观察,同时设空白对照组。结果表明,口服伊维菌素干混悬剂0.2,0.3mg/kg剂量组绵羊的羊狂蝇蛆驱净率和驱虫率均达100%。口服0.1mg/kg剂量组绵羊的羊狂蝇蛆驱净率93.9%、驱虫率98.6%。试验证明伊维菌素干混悬剂对羊狂蝇蛆驱虫效果明显,临床使用0.2mg/kg体重剂量高效安全。     

伊维菌素干混悬剂对绵羊寄生虫的驱除试验

伊维菌素是一种具有广谱、高效、低毒特点的抗生素类抗寄生虫药物,已有多种兽医临床使用的制剂产品,在生产中应用其防治效果满意.伊维菌素干混悬剂是使用方便的新剂型,为进一步观察其对绵羊线虫和部分蜘蛛昆虫的临床药效,笔者等进行了本项试验,报告如下.     

伊维菌素干混悬剂驱除猪蛔虫效果与安全性试验

应用伊维菌素干混悬剂进行了驱除猪蛔虫的效力及安全性试验。结果：0．3mg/kg b.w剂量对猪蛔虫的虫卵转阴率、虫卵减少率和驱虫率均达100％，猪可耐受1．5mg/kg剂量。试验证明伊维菌素干混悬剂驱除猪蛔虫安全高效，投药方便，成本较低，具有推广前景。     

伊维菌素干混悬剂对绵羊线虫病的防治效果观察

线虫病是放牧绵羊常见的重要寄生虫病之一,常引起感染羊的春季虫性腹泻和瘦弱死亡。依据其当地流行规律,掌握好驱虫时间和选用广谱、高效、低毒药物及其使用方便的剂型,才能获得良好的防治效果。伊维菌素是广谱抗线虫、节肢动物药物,已广泛用于兽医临床防治畜禽的多种寄生虫病。伊维菌素干混悬剂是一种使用方便的新剂型。在已有试验的基础上,我们于2005年5月应用本品进行了对绵羊线虫病的防治效果观察。现报告如下。     

伊维菌素注射液对绵羊内外寄生虫驱除试验

用伊维菌素分低、中、高3个剂量组对60只绵羊进行了驱虫试验，结果表明，伊维菌素对绵羊鼻蝇的驱除率90％以上，虫卵减少率分别为82．4％、96．0％和96．4％。驱虫的最佳剂量为0．02ml／kg体重．     

伊维菌素浇泼剂防治绵羊寄生虫病的效果观察

应用伊维菌素浇泼剂,驱除绵羊体内线虫和体外寄生虫,结果表明,0．5mg／kg体重剂量对主要7属消化道线虫和网尾线虫的虫卵（幼虫）转阴率、减少率均为100％,对原圆科线虫幼虫转阴率、减少率分别为87．59／6和91．3％,对线虫的总计驱虫率为99．04％;对绵羊颚虱的杀虫率达100％。表明伊维菌素浇泼剂0．5mg／kg剂量一次用药,驱除绵羊体内线虫和体外绵羊颚虱等寄生虫,高效安全。     

伊维菌素对绵羊体表寄生虫的影响

为了研究伊维菌素浇泼剂对绵羊体表寄生虫的效果,本实验在不同温度下应用0.5%伊维菌素浇泼剂按0.2、0.5、0.8mg/kg·bw剂量对绵羊沿背中线皮肤一次浇泼给药,并以不浇泼伊维菌素做对照,以羊颚虱和羊蜱蝇转阴率为考察指标,评判不同剂量和不同温度下伊维菌素浇泼剂驱杀绵羊体表寄生虫效果。实验结果表明,0.2mg/kg·bw、0.5mg/kg·bw和0.8mg/kg·bw伊维菌素浇泼剂对羊颚虱转阴率分别为95%、100%和100%,对羊蜱蝇转阴率分别为81.3%、85.7%和92.8%。随着平均温度从13.8℃升高到28.9℃,伊维菌素对羊颚虱和羊蜱蝇转阴率逐渐降低。     

伊维菌素干粉混悬剂对绵羊体内外寄生虫驱杀效果试验

羊胃肠道线虫病、绵羊颚虱、羊蜱蝇病等一直是影响我场牧业生产的绵羊主要寄生虫病 ,长期以来控制寄生虫病危害是本场畜疫防治工作的重要内容之一 ,多年来采用口服丙硫咪唑片剂防治蠕虫病 ,应用杀虫剂药浴或喷淋杀灭体外寄生虫 ,防治效果良好。但由于长期重复使用 ,有时达不到预期防治效果 ,并存在驱杀内外寄生虫需多次用药等弊端。为了寻求新型优良驱杀虫药物及其使用方便的剂型 ,我们选择伊维菌素(Ｉｖｅｒｒｍｅｃｔｉｎ)干粉混悬剂 ,进行了本项试验 ,结果如下 :1　材料和方法1 1　试验药物 :伊维菌素干粉混悬剂 ,2 5 0ｍｌ瓶装 ,白色粉…     

伊维菌素干混悬剂对绒山羊线虫病的防治效果

线虫病是绒山羊常见的重要寄生虫病之一,每年冬春季节常引起绒山羊的腹泻。因此,掌握好绒山羊的驱虫时间和选用广谱、高效、低毒以及使用方便的药物至关重要。伊维菌素是广谱抗线虫和节肢动物的药物,已被广泛用于兽医临床中多种寄生虫病的防治。伊维菌素干混悬剂是一种使用方便     

阿苯达唑干混悬剂驱除绵羊线虫的效力与安全性试验

应用阿苯达唑干混悬剂按10mg/kg、15mg/kg、20mg/kg剂量驱除绵羊线虫,并设药物对照组和空白对照组。粪检结果:阿苯达唑干混悬剂三个试验剂量组对羊消化道线虫虫卵转阴率分别为83.3%、93.3%和96.7%,减少率分别为95.2%、98.8%和99.9%;对原圆科线虫幼虫转阴率分别为63.3%、83.3%和93.3%,减少率分别为76.1%、87.5%和94.2%。剖检结果:三个剂量组对线虫的总计驱虫率分别为96.9%、98.3%和99.4%。阿苯达唑原料药15mg/kg剂量对羊消化道线虫虫卵转阴率、减少率分别为90%和98.5%,对原圆科线虫幼虫转阴率、减少率分别为83.3%和86.9%,总计驱虫率98.5%。绵羊能耐受80mg/kg剂量。试验证明:阿苯达唑干混悬剂的驱虫活性及安全性与阿苯达唑原料药、片剂等无明显差异,均有良好驱虫效果,临床驱除绵羊线虫使用剂量以15mg/kg为宜,干混悬剂使用方法简便,特别适用于高原牧区,具有推广价值。     

Assessment of the long‐acting ivermectin formulation in sheep: Further insight into potential pharmacokinetic interactions

The aim of the current study was to evaluate the in vivo pharmacokinetic of ivermectin (IVM) after the administration of a long‐acting (LA) formulation to sheep and its impact on potential drug‐drug interactions. The work included the evaluation of the comparative plasma profiles of IVM administered at a single therapeutic dose (200 μg/kg) and as LA formulation at 630 μg/kg. Additionally, IVM was measured in different gastrointestinal tissues at 15 days posttreatment with both IVM formulations. The impact of the long‐lasting and enhanced IVM exposure on the disposition kinetics of abamectin (ABM) was also assessed. Plasma (IVM and ABM) and gastrointestinal (IVM) concentrations were analyzed by HPLC with fluorescent detection. In plasma, the calculated C_max and AUC_0‐t values of the IVM‐LA formulation were 1.47‐ and 3.35‐fold higher compared with IVM 1% formulation, respectively. The T_1/2ab and T_max collected after administration of the LA formulation were 2‐ and 3.5‐fold longer than those observed after administration of IVM 1% formulation, respectively. Significantly higher IVM concentrations were measured in the intestine mucosal tissues and luminal contents with the LA formulation, and in the liver, the increase was 7‐fold higher than conventional formulation. There was no drug interaction between IVM and ABM after the single administration of ABM at 15 days post‐administration of the IVM LA formulation. The characterization of the kinetic behavior of the LA formulation to sheep and its potential influence on drug‐drug interactions is a further contribution to the field.     

Pharmacokinetics of ivermectin in sheep following pretreatment with Escherichia coli endotoxin

The comparative pharmacokinetics of ivermectin (IVM), between healthy and in Escherichia coli lipopolysaccharides (LPS) injected sheep, was investigated after an intravenous (IV) administration of a single dose of 0.2 mg/kg. Ten Suffolk Down sheep, 55 ± 3.3 kg, were distributed in two experimental groups: Group 1 (LPS): treated with three doses of 1 μg LPS/kg bw at ?24, ?16, and ?0.75 hr before IVM; group 2 (Control): treated with saline solution (SS). An IV dose of 0.2 mg IVM/kg was administered 45 min after the last injection of LPS or SS. Plasma concentrations of IVM were determined by liquid chromatography. Pharmacokinetic parameters were calculated based on non‐compartmental modeling. In healthy sheep, the values of the pharmacokinetic parameters were as follows: elimination half‐life (2.85 days), mean residence time (MRT) (2.27 days), area under the plasma concentration curve over time (AUC, 117.4 ng day^?1 ml^?1), volume of distribution (875.6 ml/kg), and clearance (187.1 ml/day). No statistically significant differences were observed when compared with the results obtained from the group of sheep treated with LPS. It is concluded that the acute inflammatory response (AIR) induced by the intravenous administration of E. coli LPS in adult sheep produced no changes in plasma concentrations or in the pharmacokinetic behavior of IVM, when it is administered intravenously at therapeutic doses.     

Field trials evaluating ivermectin controlled-release capsules for weaner sheep and for breeding ewes

Objective To confirm the efficacy of ivermectin released from a controlled-release capsule administered to young sheep and to breeding ewes under field conditions. Design Randomised field trials. Procedure In each of ten field trials 25 weaned lambs were treated with ivermectin controlled-release capsules and 25 remained untreated. Eight similar field trials were conducted using adult ewes. Efficacy against infections of gastrointestinal nematodes was assessed by faecal egg counts and faecal larval culture. Body weights were recorded and faecal soiling of the breech wool (dags) was assessed. Results Nematode faecal egg counts in the two groups were not different (P = 0.13) before treatment in the weaner trials or before treatment in the ewe trials (P = 0.49), but thereafter eggs in the untreated sheep persisted, whereas counts in sheep given capsules were negligible (P ≤ 0.01). In the weaner trials, dag scores for the two groups were not different at the start of the trials (P = 0.18) but at the end, untreated sheep had significantly more dags (P = 0.04) than treated sheep. In the ewe trials, dag scores remained low in both groups. Weaners treated with the capsule gained 1.4 kg (95% CL: 0.7, 3.1) more weight over the 16 week trial period compared to untreated weaners (P = 0.01). Both groups of ewes lost weight as a result of parturition but the mean loss by week 16 was greater for untreated (3.7 kg) (95% CL: -5.1,-2.2) than for treated ewes (1.8 kg) (95% CL: -3.3, -0.4). The mean change in ewe body weight for the two groups was however not significant (P = 0.07). Differentiation of nematode larvae recovered from cultures of faeces from untreated animals indicated that the capsules were effective against the common parasites of sheep. Conclusion The capsule was efficacious against gastrointestinal nematodes judging from faecal egg counts. It has the potential to significantly reduce contamination of pasture with nematode eggs. Treated weaners had less dags for 16 weeks and gained more weight than untreated weaners.     

Efficacy of an ivermectin controlled-release capsule against some rarer nematode parasites of sheep

A controlled trial was conducted to evaluate the efficacy of the intraruminal ivermectin controlled-release capsule (CRC) (IVOMEC Maximizer CR Capsule for Sheep, Merial Ltd.) against induced incoming third-stage larvae and established adult infections with some rarer gastrointestinal nematode parasites of sheep. Twenty-one worm-free lambs were allocated by restricted randomisation based on body weight within sex to one of the following treatments: unmedicated control, ivermectin CRC given on Day 0 prior to induced infection, and ivermectin CRC given on Day 70 after establishment of induced infection. The ivermectin CRC delivers ivermectin at a minimum dose rate of 20 microg/kg/day for 100 days. Infections were induced by daily administration of third-stage larvae for five consecutive days. Nematodes were counted on Day 84, 14 days after treatment of established infection. The treatment with the ivermectin CRC prevented the establishment of Ostertagia leptospicularis, O. ostertagi, Bunostomum trigonocephalum, Cooperia oncophora, C. punctata, C. surnabada, Nematodirus helvetianus, N. roscidus and Strongyloides papillosus by >99% as compared with the untreated controls (p < 0.01). The administration of the ivermectin CRC reduced established adult infections of O. ostertagi, B. trigonocephalum, C. oncophora, C. punctata, C. surnabada, N. roscidus and S. papillosus by >99% (p < 0.01), and reduced established adult infections of O. leptospicularis and N. helvetianus by 96.5 and 98.4% (p < 0.01), respectively.     

Ivermectin-resistant Ostertagia circumcincta from sheep in the lower North Island and their susceptibility to other macrocyclic lactone anthelmintics

Aim: To confirm the ivermectin resistance status of a strain of Ostertagia circumcincta which was isolated from a sheep farm in the lower North Island of New Zealand and to assess the susceptibility of this strain to other macrocycliclactone anthelmintics.

Methods: Twenty-five lambs housed indoors were each infected with 12,000 L3 larvae of the above parasite strain. Approximately 3 weeks after infection the lambs were allocated to 1 of 4 treatment groups (3 groups of 6, and 1 group of 7 lambs), one of which remained untreated while the others were drenched orally with ivermectin, moxidectin or abamectin at 0.2 mg/kg liveweight. Faecal egg counts (FECs) before and after treatment, and post-mortem worm burdens 10 days after treatment were examined to assess efficacies of each anthelmintic.

Results: Treatment with ivermectin reduced the mean FEC by only 18% and the mean worm burden by only 42%, whereas moxidectin and abamectin reduced FECs by > 92% and worm burdens by >95%.

Conclusion: These results, together with a similar case described recently from the South Island, confirm the emergence of ivermectin resistance in nematode parasites of sheep in New Zealand. The superior efficacy of moxidectin and abamectin in this case indicates that, following the emergence of resistance to ivermectin, some short-term practical use may still be made of these other anthelmintics. However, their continued use will undoubtedly result in increased levels of resistance and eventual therapeutic failure of these products also.     

高寒牧区天然草地牧草干物质的瘤胃降解率动态变化

选用5只安装有瘤胃瘘管,体重和体质相近,健康无病的德国美利奴×小尾寒羊为试验羊只,采用瘤胃尼龙袋法测定2010~2012年不同月玛曲高寒草地天然牧草瘤胃降解率动态变化,结果表明,天然牧草在瘤胃中降解48h后其干物质瘤胃降解率趋于平缓。牧草瘤胃干物质降解率随生育期的推移先升高后降低,在6、7月出现了峰值,2010年7月,2011和2012年6月分别达到67.05%,60.9%和71.56%。此时牧草营养价值较高,完全可以满足家畜对营养素的需求,8、9月逐渐下降;不同年份相同草地牧草干物质降解率也不同。