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1.
盐酸克林霉素按每公斤体重 11mg单一剂量肌肉注射 ,分别观察了其在健康猪 (n=5 )和链球菌感染猪 (n =5 )体内的药代动力学。用高效液相色谱法测定盐酸克林霉素的血药浓度 ,所得血药浓度 -时间数据采用 MCPKP软件进行分析。在健康猪体内的药代动力学参数如下 :Cmax为 (2 .5 46 43± 0 .2 2 42 ) mg/ L,T1 /2 为 (3.2 10± 0 .795 3) h,AUC为(17.86 5 72± 1.2 5 46 ) m g· h/ L ,Tmax为 (2 .18796± 0 .44 37) h。在链球菌感染猪体内的药代动力学参数如下 :Cmax为(2 .5 5 6 89± 0 .12 45 ) mg/ L ,T1 /2 为 (2 .6 912 3± 0 .8895 2 ) h,AUC为 (12 .0 0 6 5 4± 3.2 5 46 ) mg· h/ L ,Tmax为(1.16 176± 0 .5 436 ) h。  相似文献   

2.
将 1 5头健康杂交奶山羊均分成 3组 ,按每千克体重 5mg的剂量分别对大肠杆菌内毒素诱导的乳房炎奶山羊进行静注、肌注和乳房灌注单剂量环丙沙星药动学试验。高效液相色谱法测定血、乳及组织药物浓度 ,血药浓度 -时间数据用 MCPKP药动学程序处理。诱导乳房炎的奶山羊静注给药的药时数据符合二室开放模型 ,主要药动学参数分别为 :t1 /2α为 ( 0 .0 9± 0 .0 1 ) h,t1 /2β为 ( 1 .1 0± 0 .0 9) h,Vd( area) 为 ( 2 .80± 0 .3 0 ) L/kg,Cl B为 ( 1 .3 1± 0 .2 1 ) L/ ( kg·h- 1 ) ,AUC为 ( 3 .88± 0 .58) mg/ ( L· h- 1 )。肌注给药的药时数据符合一级吸收二室开放模型 ,主要药动学参数分别为 :t1 /2 Kα为 ( 0 .0 7± 0 .0 2 ) h,t1 /2α为 ( 0 .3 9± 0 .2 6) h,t1 /2β为 ( 2 .0 7±0 .4 3 ) h,tmax为 ( 0 .2 6± 0 .0 7) h,Cmax为 ( 1 .0 4± 0 .1 3 ) mg/ L,AUC为 ( 2 .3 8± 0 .1 3 ) mg/ ( L· h- 1 ) ,F为61 .3 4 %。与从健康奶山羊获得的药动学参数相比 ,急性乳房炎能显著影响环丙沙星静注给药的体内分布、转运和消除 ,对肌注给药无明显影响 ,乳房灌注给药在炎症乳房内的吸收个体差异较大。急性乳房炎能显著降低环丙沙星全身给药在乳内积聚程度。肌注后炎症乳腺组织内药物浓度在 2、4、6、8  相似文献   

3.
对 5头健康猪口服和静脉注射国产硫酸安普霉素 ,研究其在猪体内的药代动力学和生物利用度。用微生物法测定血清药物浓度 ,结果平均回收率为 99.0 3%,血清最低检测浓度为 0 .0 5 μg/ ml,日内日间变异系数为 2 .2 %~ 5 .0 %,且血清浓度在0 .0 5~ 3μg/ m l范围呈良好线性关系 (r=0 .996 5 )。以 2 0 mg/ kg口服和以 2 0 mg/ kg静脉注射硫酸安普霉素后 ,经 Mcpkp药代动力学计算机程序处理 ,体内药物运转分别符合开放型一室和二室模型 ,生物半衰期 t1 / 2 分别为 (7.36± 1 .5 2 ) h和 (3.1 7± 0 .75 )h;CLB分别为 4 .82 L / kg· h和 0 .1 6 L / kg· h;AUC值分别为 4 .1 4和 1 30 .6 2。口服 :Cmax为 (0 .2 4± 0 .0 3)μg/ ml;Tp为 (5 .1 2±0 .6 1 ) h;T1 / 2 K为 (7.36± 1 .5 2 ) ;生物利用度 (AUCp.0 / AUCi.v)为 (3.1 92 8± 0 .70 4 4 ) %。上述药代动力学数据为动物临床用药提供有价值的理论依据  相似文献   

4.
麻保沙星(marbofloxacin)在猪体内的药物动力学   总被引:6,自引:0,他引:6  
选用 18头健康的杜洛克×大白×长白三元杂交断奶仔猪 (公母兼有 ,体质量在 2 0~ 2 3kg)杂交猪 ,随机分为 3组 ,每组 6头 ,按每千克体质量 2 .5 mg的剂量进行了静注、肌注及内服麻保沙星 (m arbofloxacin)的药动学研究。三氯甲烷萃取血浆中的药物 ,用反相高效液相色谱法测定血浆中药物的浓度 ,MCPKP药代动力学程序处理血药浓度 -时间数据。静注给药的药时数据符合三室开放模型 ,主要药动学参数为 :t1 /2π(0 .13± 0 .0 1) h;t1 /2α(5 .4 1± 0 .4 3) h;t1 /2β(16 .2 2± 1.6 0 ) h;AUC(2 4 .89± 1.5 1) mg· L- 1· h;V1 (0 .77± 0 .0 6 ) L· kg- 1 ;Vd( area) (2 .6 1± 0 .37) L· kg- 1 ;Vd( ss)(1.6 9± 0 .19) L· kg- 1 ;Cl B(0 .10± 0 .0 1) L· kg- 1·h。肌注给药的血浆药时数据符合一级吸收二室开放模型 ,主要药动学参数为 :t1 /2 Ka(0 .2 7± 0 .16 ) h;t1 /2α(2 .87± 0 .90 ) h;t1 /2β(17.39± 1.6 2 ) h;tmax(0 .91± 0 .32 ) h;Cmax(1.96± 0 .2 4 ) mg· L- 1 ;AU C(2 6 .85± 3.5 1) mg· L- 1 · h;F(10 7.86± 14 .10 ) %。内服给药的血浆药时数据符合一级吸收二室开放模型 ,主要药动学参数为 :t1 /2 Ka(1.16± 0 .19) h;t1 /2α(4.94± 0 .5 3) h;t1 /2β(2 2 .98± 2 .0  相似文献   

5.
4头成年健康水牛采用随机交叉实验设计,分别进行吡喹酮注射剂肌注和吡喹酮片内服给药的药动学试验.吡喹酮注射剂按10 mg/kg的剂量单次肌注,吡喹酮片按20 mg/kg的剂量单次内服给药.采用高效液相色谱法测定血浆中吡喹酮的质量浓度,方法最低检测限和定量限分别为0.01 mg/L和0.062 5 mg/L.吡喹酮注射剂单剂量肌注给药,血药浓度-时间数据符合一级吸收一室开放模型,其主要动力学参数分别为:t1/2(ka)(0.45±0.029)h,t1/2(ke)(5.04±0.1 0)h,T(peak)(1.72±0.029)h,C(max)(0.87±0.006)mg/L,V(c)(8.58±0.010)L/kg,AUC(7.99±0.005)mg·L-1·h-1.吡喹酮片单剂量口服给药血药浓度-时间数据符合有吸收-室开放模型,其主要动力学参数分别为:Lagtime(0.13±0.010)h,t1/2(ka)(0.76±0.11)h,t1/2(ke),(1.31±0.076)h,T(peak)(3.84±0.026)h,C(max)(0.51±0.006)mg/L,V(c)(26.07±1.221)L/kg,AUC(7.99±0.005)mg·L-11·h-1.肌注相对生物利用度为(232±12.9)%.研究结果表明,20%吡喹酮注射剂肌注给药吸收迅速且完全,具有较高的生物利用度;吡喹酮吸收后在体内广泛分布.  相似文献   

6.
单剂量氟苯尼考内服及肌注在家兔体内药代动力学研究   总被引:1,自引:0,他引:1  
健康新西兰白兔20只,随机分为A、B 2组,A组内服单剂量30 mg/kg氟苯尼考试验品,B组肌注单荆量30mg/kg氟苯尼考试验品.用高效液相色谱法测定血浆中的药物浓度,3p97药代动力学程序软件处理药--时数据,A组药--时数据符合--室开放模型(W=1/C2),主要药代动力学参数T1/2Ka=(0.461±0.066)h,T1/2ke=(2.013±0.195)h,Tpeak=(1.180±0.123)h,Cmax=(7.332±1.000)mg/L,AUC=(31.445±3.566)mg·L-1·h,V/F=(2.995±0.330)L/kg;B组药-时数据也符合一室开放模型(W=1/C2),主要药代动力学参数T1/2Ka=(0.802±0.098)h,T1/2ke=(2.317±0.136)h,Tpeak=(1.805±0.103)h,Cmax=(6.646±0.578)mg/L,AUC=(38.714±3.727)mg·L-1·h,V/F=(2.772±0.303)L/kg.试验结果表明,氟苯尼考在家兔体内主要药动学特征为内服吸收迅速、分布快而广、消除较快;肌注吸收速度显著慢于内服.分布广泛,消除也较快.  相似文献   

7.
盐酸多西环素缓释注射液在猪体内的药物动力学   总被引:2,自引:0,他引:2  
健康猪6头,体质量(17.85±1.3)kg,按拉丁方设计进行单剂量静注、肌注盐酸多西环素注射液(普通制剂)和肌注盐酸多西环素缓释注射液,注射剂量按多西环素计均为20 mg/kg,比较盐酸多西环素缓释注射液和盐酸多西环素注射液在猪体内的药动学特征和生物利用度.用高效液相色谱法测定其血药浓度,试验所得的血药浓度-时间数据采用非房室模型统计矩原理分析处理.猪静注盐酸多西环素注射液的主要药物动力学参数为AUC(108.15±13,25)mg·h·L-1,MRT(5.56±1.08)h,CI(0.19±0.02)L·h-1·kg-1,Vd(ss)(1.04±0.09)L·kg-1,t1/2(4.07±0.65)h.猪肌注盐酸多西环素注射液和盐酸多西环素缓释注射液的主要药物动力学参数分别为MRT(15.18±2.13)h和(22.25±3.49)h;Tmax(1.135±0.44)h和(2.0±0.63)h;Cmax(3.32±0.33)mg·L-1和(3.10±0.29)mg·L-1;AUC(38.91±4.35)mg·h·L-1和(61.72±10.16)mg·h·L-1;F(36.66±7.88)%和(57.66±10.75)%.比较盐酸多西环素注射液和盐酸多西环素缓释注射液的主要药动学参数,除了Cmax以外,MRT、Tmax、AUC、F等主要参数均有显著的统计学意义(P<0.05).这表明盐酸多西环素缓释注射液肌注后吸收缓慢.消除半衰期延长,临床用药48 h给药1次仍能维持对常见病原菌的有效血药浓度.  相似文献   

8.
本研究旨在考察国产麻保沙星溶液在健康犬体内的药动学特征及生物利用度.选用8只健康犬,按照随机拉丁方设计,进行单次不同单剂量(2.75 mg·kg-1)分别静注麻保沙星溶液和口服麻保沙星溶液制剂.血浆样品经乙腈沉淀血浆蛋白,高速离心,用反相高效液相色谱法测定犬血浆中麻保沙星的浓度,3P97药动学计算软件处理血浆药物浓度-时间数据.健康犬静注给药的药物动力学最佳数学模型为无吸收开放二室模型,主要药动学参数为:T1/2α(0.34±0.14)h,T1/2β(7.74±1.70)h,V(1.03±0.60)L·kg-1,CL(0.22±0.08)L·h-1;AUC(14.05±4.25)mg·mL-1·h.口服给药的药物动力学最佳数学模型为一级吸收二室模型.主要药动学参数为:T1/2α((2.82±1.86)h,T1/2β(16.03±9.27)h,V/F(2.25±0.34)L·kg-1,CL/F(0.21±0.05)L·h-1,Tmax(1.55±0.62)h,Cmax(0.89±0.21)μg·mL-1,AUC(13.66±2.77)mg·mL-1·h.肌注麻保沙星冻干粉针的生物利用度为97.22%.麻保沙星在健康犬体内口服的主要药动学特征为吸收较快,达峰时间短,半衰期较长,生物利用度高.  相似文献   

9.
《畜牧与兽医》2016,(5):122-125
为将绿原酸引入奶牛乳房炎的治疗,进行了绿原酸在奶山羊体内的药动学研究。本试验制备了奶山羊大肠杆菌性乳房炎病理模型,建立了反相高效液相色谱检测血清中绿原酸含量的方法,测定了静注、肌注绿原酸在健康奶山羊及乳房炎病理模型奶山羊体内的药动学参数,初步反映了绿原酸在奶山羊体内的动力学过程。经试验测定绿原酸在健康奶山羊体内,静注后呈二室开放模型,其药动学参数CO(μg/m L)为20.66±6.13,T1/2β(min)为7.27±1.19,CLB(L/kg·min-1)为0.27±0.34,AUC(mg/L·min-1)为81.83±14.87;肌注后呈一级吸收一室开放模型,其药动学参数Cmax(μg/m L)为0.40±0.11,AUC(mg/L·min-1)为41.54±17.16。绝对生物利用度平均为47。绿原酸在乳房炎奶山羊体内静注后呈二室开放模型,其药动学参数CO(μg/m L)为23.03±6.97,t1/2β(min)为9.01±4.16,AUC(mg/L·min)为96.68±16.93,CLB(L/kg·min-1)为0.10±0.02;肌注后呈一级吸收一室开放模型,其药动学参数Cmax(μg/m L)为0.48±0.37,AUC(mg/L·min)为38.02±23.69。绝对生物利用度平均为43%。  相似文献   

10.
为了研究阿莫西林混悬注射液在猪体内的药代动力学和生物等效性,采用双处理、双周期随机交叉试验设计,将24头健康猪随机分成2组,按15 mg/kg体重肌肉分别单剂量注射受试制剂和参比制剂,采用高效液相色谱法测定血浆中阿莫西林的浓度,利用Win Nonlin6.4软件计算主要药动学参数,并评价两种制剂的生物等效性。结果显示,受试制剂和参比制剂的Tmax分别为(3.45±2.49)h,(1.34±1.74)h;Cmax分别为(6.94±4.73)mg/L,(4.39±2.87)mg/L;AUC0-t分别为(37.00±11.48)mg·h·L-1,(30.02±8.93)mg·h·L-1;AUC0-∞分别为(40.26±13.36)mg·h·L-1,(38.46±15.38)mg·h·L-1。阿莫西林混悬注射液受试制剂和参比制剂的AUC0-t、AUC0-∞、Cmax、Tmax均有显著性差异,双单侧t检验结果显示两种制剂生物不等效,试验为兽医临床给药方案的制定以及合理用药提供参考。  相似文献   

11.
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。  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

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