甘草提取物对左氧氟沙星在鸡体内药动学的影响

将20只鸡随机分成对照组和试验组,对照组单剂量灌胃给予左氧氟沙星(levofloxacin,LVLX)10mg/kg;试验组左氧氟沙星10mg/kg与甘草提取物0.3g/kg合用。采用HPLC法测定血药质量浓度,并以DAS2.0软件计算并比较主要药动学参数。结果显示:对照组和试验组左氧氟沙星的主要药动学参数C_(max)分别为(1.415±0.116)、(1.321±0.165)mg/L,t_(max)分别为(1.983±0.172)、(2.365±0.325)h,AUC_(0~36h)分别为(8.659±0.852)、(9.415±1.176)mg·L~(-1)·h~(-1),t_(1/2)分别为(3.714±0.674)、(8.341±0.853)h,MRT_(0~36h)分别为(4.116±0.238)、(6.648±0.676)h,Vz/F分别为(3.154±0.296)、(3.315±0.436)L/kg。与对照组相比,试验组药动学参数C_(max)降低,AUC_(0~36h)、Vz/F增大,但差异均不显著(P0.05);t_(max)、t_(1/2)、MRT_(0~36h)均极显著增大(P0.01)。结果表明:合用甘草提取物和左氧氟沙星,甘草提取物能减慢左氧氟沙星在体内的吸收和消除速度,延长药物在体内的作用时间。     

桔梗的"引经"作用对左旋氧氟沙星在鸡体内药物分布的影响

72只25日龄健康黄杂鸡随机均分为2组，Ⅰ组单剂量内服左氧氟沙星（10mg／kg），Ⅱ组左氧氟沙星（10mg／kg）与桔梗煎液（2g／kg）联合内服。采用高效液相色谱法测定鸡体内不同组织中药物的浓度。结果表明，桔梗与左氧氟沙星联用，明显影响了左氧氟沙星在健康鸡体内的分布，其中，肺、心、肾组织最高药物浓度较单用左氧氟沙星组显著增高，而肝脏的药物浓度较单用左氧氟沙星有所降低。     

桔梗对左氧氟沙星在健康鸡体内药动学影响的研究

为研究桔梗对左氧氟沙星（LVLX）在健康鸡体内的血药浓度及药动学参数的影响，72只健康鸡随机平均分成2组，Ⅰ组单剂量灌胃给予左氧氟沙星（10mg／kg）；Ⅱ组左氧氟沙星（10mg／kg）与桔梗煎液（2g／kg）联用。采用高效液相色谱法测定血药浓度，最低检测限0．001mg／L，并以3P97药动学程序进行分析，药时数据均符合一级吸收二室模型（权重=1）。与Ⅰ组相比，Ⅱ组的药动学参数有如下变化：T1/2α、T1/2ka增大，Cmax、ka降低，差异均不显著（P〉0．05）；T1/2β、Tmax、AUC、MRT0-36均极显著增加（P〈0．01）。结果表明：桔梗对左氧氟沙星在健康鸡体内的药物代谢有较大影响；减慢LVLX在体内的吸收速度，但增加了LVLX吸收的程度；加快了LVLX向组织的转运；减慢了LVLX在鸡体内的消除速度，延长了药物在体内的作用时间。     

甘草提取物对氟苯尼考在鸡体内药动学和生物利用度的影响

为研究甘草提取物对氟苯尼考(florfenicol,FFC)在鸡体内药动学和生物利用度的影响,将30只鸡随机分成单用组、合用组和静脉组,合用组连续7 d灌服甘草提取物(0.3 g/kg,1次/d),单用组和静脉组则给予相同体积的生理盐水,第8天3个组均予FFC(30 mg/kg)给药后按时间点连续采样,数据采用DAS2.0进行分析。结果显示,单用组和合用组FFC的主要药动学参数:C_(max)分别为(5.637±0.825),(5.289±0.734) mg/L,T_(max)分别为(1.518±0.428),(1.083±0.343) h,AUC_(0-∞)分别为(30.774±5.683),(24.561±5.364) mg/L·h,t_(1/2z)分别为(2.472±0.314),(2.066±0.272) h,MRT分别为(3.149±0.459),(2.614±0.385) h,Vz分别为(4.466±0.375),(5.253±0.498) L/kg,CLz分别为(1.168±0.136),(1.401±0.152) L/h·kg。合用后,FFC药动学特征出现明显改变,AUC_(0-∞)、MRT、t_(1/2z)、T_(max)均显著降低(P0.05),C_(max)降低(P0.05),Vz和CLz则显著增加(P0.05),口服生物利用度下降了16.26%。结果表明,甘草提取物连续给药7 d后加快了FFC在鸡体内的吸收和消除速度,减小了口服生物利用度,提示两者在临床上合用有潜在的药动学相互作用。     

非房室模型统计矩原理分析角黄素在鸡体内的药代动力学特征

本试验旨在利用非房室模型统计矩原理研究角黄素在鸡体内的药代动力学特征。选用19周龄海蓝蛋鸡为研究对象,角黄素以0.96mg/kg体重单剂量经口服灌胃给药,不同时间点分10次采集鸡静脉血,高效液相色谱法测定鸡血清中角黄素的质量浓度,用3p⁽⁹⁷⁾药代动力学软件的非房室模型统计矩原理分析药代动力学数据。结果显示,鸡单剂量口服角黄素的主要药动学参数分别为:T_(max)=10 h,C_(max)=0.362μg/mL,t_(1/2)=19.263,AUC_(0-t)=9.379μg/mL·h,AUC_(0-∞)=19.251μg/mL·h,MRT_(0-t)=27.964 h,MRT_(0-∞)=118.054h。上述研究表明,角黄素经口服后在鸡体内达峰快,在组织器官中分布广泛,但滞留时间很长,消除缓慢。     

黄芩素在大鼠体内对氟苯尼考药动学的影响研究

为研究黄芩素对氟苯尼考在大鼠体内药动学的影响,将12只大鼠随机分成单用组、合用组,合用组连续7 d灌服黄芩素(50 mg/kg,1次/d),单用组则给予相同体积的生理盐水,第8 d两组大鼠均按25 mg/kg剂量灌服氟苯尼考,给药后按时间点连续采样,数据采用DAS2.0分析。试验结果表明,黄芩素连续给药7 d,可以增加氟苯尼考在大鼠体内的吸收,减缓代谢消除,提高口服生物利用度,提示这两种药物在临床上合用具有潜在的药动学相互作用。     

恩诺沙星及其代谢物在1日龄鸡体内的药动学研究

研究不同剂量恩诺沙星(ENR)及代谢产物环丙沙星(CIP)在雏鸡体内药动学特征。240只刚出壳黄羽肉鸡分2个剂量组,20 mg/kg和40 mg/kg皮下注射恩诺沙星,高效液相色谱法测定药物浓度,药时数据用WinNolin8.0软件处理非房室模型分析。结果表明,增加剂量后恩诺沙星以下药动参数发生变化:消除半衰期(t_(1/2))由7.37 h降至6.53 h,达峰时间(T_(max))由8 h降到4 h,最大血药浓度(C_(max))由3.75μg/mL增至4.92μg/mL,药时曲线下面积(AUC_(last))由40.45 h·μg/mL增至78.2 h·μg/mL,平均滞留时间(MRT_(last))由为8.6 h增至11.42 h;消除率(Cl)分别为0.49 L/h/kg和0.5 L/h/kg,表观分布容积(Vz_(obs))分别为5.22 L/kg和4.77 L/kg。不同剂量恩诺沙星给药后都都表现出分布迅速、广泛的特点,代谢产物环丙沙星产生与消除迅速。     

山银花提取物对肉鸡口服氟苯尼考药代动力学及代谢转运相关基因表达的影响

为研究山银花提取物对鸡口服氟苯尼考药代动力学的影响及其作用机制,将30只健康肉公鸡随机平均分成对照组与山银花组,其中山银花组连续7 d灌服山银花提取物(0.20 g/kg, 1次/d),对照组则给予相同体积的生理盐水,第8天时选取各组10只鸡按30 mg/kg灌服氟苯尼考,给药后按时间点连续采样,高效液相色谱法(HPLC)检测氟苯尼考血药浓度;2组另5只则按荧光定量RT-PCR方法检测肝脏和空肠中细胞色素P450 3A37(CYP3A37)、葡萄糖醛酸转移酶1E(UGT1E)、多药耐药基因1(MDR1)和鸡外源性核受体(CXR)mRNA表达。结果显示:山银花组药-时曲线下面积(AUC_(0～24 h))和平均滞留时间(MRT_(0～24 h))显著增加(P0.05),表观清除率(CLz)显著降低(P0.05);与对照组相比,山银花组肝脏和空肠中CYP3A37、UGT1E、CXR mRNA表达显著降低(P0.05),肝脏、空肠MDR1 mRNA表达无显著差异(P0.05)。结果表明:联用山银花后,氟苯尼考在鸡体内药代动力学参数(AUC、MRT和CLz)发生显著变化,可能与山银花抑制CYP3A37、UGT1E、CXR mRNA在肝脏和空肠的表达有关。     

二甲苯胺噻嗪对大鼠血浆、下丘脑和垂体中β-内啡肽含量的影响

应用放射免疫学方法 ,检测腹腔注射二甲苯胺噻嗪后大鼠血浆、下丘脑和垂体中 β-内啡肽 (β- Ep)含量的变化 ,以研究二甲苯胺噻嗪对大鼠体内β- Ep的影响。结果 ,不同时间组与对照组相比 ,血浆在给药后 5 min即有统计学意义(P <0 .0 1) ,大约在 30 m in时达到最高峰 ,然后缓慢下降 ,其中麻醉组持续到给药后 12 0 min(P <0 .0 1) ,而镇痛组只持续到给药后 90 min。不同剂量组与对照组相比 ,下丘脑的 4mg/kg组无显著性差异 (P >0 .0 5 ) ,血浆的 4mg/kg组、垂体的 4mg/kg组差异有显著意义 (P <0 .0 5 ) ,其他组有极显著意义 (P <0 .0 1)。随着给药剂量的增加 ,组织内的β- Ep含量变化呈增加的趋势 ,这种趋势经相关分析表明 ,给药剂量在 4～ 6 0 mg/kg的范围内时 ,组织内的β- Ep含量与给药剂量呈正的直线相关关系 (r血浆 =0 .9748,r下丘脑 =0 .96 7,r垂体 =0 .977,均 P <0 .0 1)     

仔猪脾虚状态下单剂量口服左旋氧氟沙星的药动学研究

10头健康仔猪随机均分为健康组、脾虚组 ,按 2 0mg/kg的剂量进行内服左旋氧氟沙星的药动学研究。高效液相色谱法测定血浆中药物浓度 ,3P97药代动力学程序处理药时数据。健康组和脾虚组药动学数据适合一级吸收一室模型。健康组主要药动学数据为 :吸收半衰期 (t1 / 2ka)(0 42± 0 0 8)h ,消除半衰期 (t1 / 2ke) (7 62± 0 38)h ,达峰时间 (tmax) (1 85± 0 2 5)h ,达峰浓度 (Cmax) (6 99± 0 92 )mg/L ,药时曲线下面积 (AUC) (90 7± 1 0 0 7)mg·L- 1 ·h ,表观分布容积 (V/ F(s) ) (2 45± 0 2 8)L·kg,平均滞留时间 (MRT) (1 1 92± 0 94)h。脾虚组 :t1 / 2ka(1 1 7± 0 38)h ,t1 / 2ke (9 0 2± 1 1 8)h ,tmax (3 93± 1 0 5)h ,Cmax (4 2 8± 1 45)mg/L ,AUC (72 2 1± 1 6 0 7)mg·L- 1 ·h ,V/ F(s) (3 95±1 2 8)L·kg,MRT (1 3 74± 1 2 1 )h。结果表明 :仔猪脾虚状态下明显影响左旋氧氟沙星内服给药的药动学特征     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.