Managing anthelmintic resistance: Is it feasible in New Zealand to delay the emergence of resistance to a new anthelmintic class?     

DM Leathwick  BC Hosking  SA Bisset  CH McKay 《New Zealand veterinary journal》2013,61(4):181-192

The recent registration in New Zealand of the first new class of broad-spectrum anthelmintic, for use against nematode parasites of ruminants, in nearly three decades has raised the possibility that parasite management practices could be improved to minimise the emergence of resistance to the new drug. A review of knowledge pertaining to the selection of anthelmintic resistance in nematode parasites of sheep highlights a number of management practices which could be altered to achieve this.

A number of previously common practices such as whole-flock treatment of adult ewes around lambing, and treatment of lambs as they are moved onto pastures with low parasite contamination have been clearly identified as high risk for selecting resistant parasites. Once high-risk practices have been identified steps can be taken to either eliminate their use or mitigate the associated risk. Much of the focus on the management of resistance around the world is on the retention of susceptible genotypes in refugia. While approaches to retaining unselected parasites are likely to vary around the world, empirical studies indicate that the practice is likely to be effective at slowing the development of resistance. The challenge for farmers and advisors will be to strike a balance between retaining sufficient susceptible para-sites to usefully delay the development of resistance while not unduly compromising animal performance and farm profitability. The merits of combining different classes of anthelmintic in order to slow the development of resistance remains somewhat contentious in some countries. However, the attributes of oral anthelmintics are such that they seem likely to meet most, if not all, of the criteria for combinations to be highly effective at slowing the build-up of resistance in nematode parasites.

It is evident that considerable progress has been made in understanding the factors involved in selecting anthelmintic-resistant nematodes since the last broad-spectrum anthelmintic class was released in the early 1980s. Therefore, it should be possible to manage a new class of anthelmintic in such a way as to significantly extend its effective life. The challenge is likely to be in convincing farmers of the merits of adopting such pro-active strategies.  相似文献   

A correlation of toxicity of albendazole and oxfendazole with their free metabolites and bound residues     

P. DELATOUR  F. GARNIER  E. BENOIT  CH. LONGIN 《Journal of veterinary pharmacology and therapeutics》1984,7(2):139-145

The possible correlations between embryotoxicity, plasma kinetics of toxic metabolites and covalent binding of metabolites to foetal tissues were studied using two drugs, albendazole and oxfendazole. In the rat, the metabolic inhibitor, SKF-525A, induced changes in embryotoxicity which were well correlated with plasma levels of identified embryotoxic metabolites, but not with the levels of foetal tissue bound drug metabolites.  相似文献   

NORMAL VARIATION IN SIZE OF THE LATERAL VENTRICLES OF THE LABRADOR RETRIEVER DOG AS ASSESSED BY MAGNETIC RESONANCE IMAGING     

Constance E.  De Haan  DVM  Susan L.  Kraft  DVM  PhD  Patrick R.  Gavin  DVM  PhD  Lyle R.  Wendling  MD  Merle L.  Griebenow 《Veterinary radiology & ultrasound》1994,35(2):83-86

Detecting canine brain lesions on computed tomography (CT) or magnetic resonance (MR) scans can be difficult if the lesions do not enhance well following administration of intravenous contrast material. Changes in the shape and position of the ventricular system can be important in the diagnosis of such lesions. Normal variation within the canine ventricular system has not been documented. MR scans from 62 normal Labrador retriever type dogs were evaluated. Five dogs had symmetric enlargement of the ventricles, while nineteen dogs had mild to severe ventricular asymmetry. The incidence of asymmetry in normal dogs must be considered when using ventricular configuration as an indication of central nervous system abnormality.  相似文献   

Anthelmintic activity of milbemycin oxime against adult and immature Uncinaria stenocephala in dogs     

WL SHOOP  JR EGERTON  RL SEWARD  CH EARY  HW HAINES  BF MICHAEL 《Australian veterinary journal》1993,70(5):187-188

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Retrospective Review of 50 Canine Intracranial Tumors Evaluated by Magnetic Resonance Imaging   总被引：2，自引：0，他引：2  

Susan L. Kraft  Patrick R. Gavin DVM  Phd    Constance DeHaan  Michael Moore  Lyle R. Wendling  Charles W. Leathers 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1997,11(4):218-225

Magnetic resonance imaging (MRI) was performed on 50 dogs with intracranial neoplasia. The following tumor features were assessed: axial origin, location, shape, growth pattern, MRI signal intensity, evidence for edema, and paramagnetic contrast enhancement. Histologic diagnoses included 5 intracranially invading nasal tumors, 7 pituitary tumors, 22 meningiomas, 6 choroid plexus tumors, 7 astrocytomas, 1 ependymoma, and 2 oligodendrogliomas. Axial origin, site, shape, and growth pattern were important diagnostic characteristics for tumor type. Signal intensity and contrast enhancement pattern allowed further differentiation. Characteristic MRI features that facilitate diagnosis and prognosis were identified. Accurate diagnosis of tumor type based on these features was not always possible because of similarities in MRI appearance for some tumors. Tissue biopsy remains necessary for definitive diagnosis of intracranial tumors.  相似文献   

1997-2006年我国核心期刊研究的文献计量分析     

李强  吴淑金  罗媚娟  黄艳华  袁宁  陈清 《农业环境科学学报》2008,(4)

采用文献计量学方法,从论文分布、作者分布、发表论文的机构和地区分布、基金资助 等方面对1997-2006年中国期刊全文数据库收录的有关核心期刊研究的论文进行了统计分析 ,对其研究现状和发展趋 势进行探讨,指出了我国有关核心期刊研究的一些不足,并提出了相应的对策。

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家蚕对8种除草剂农药的毒性反应   总被引：5，自引：0，他引：5  

陈小平  严欲民  黄世群  贾利琼  唐聘芳  毛业炀  唐华伦  何炳林  陈健 《西南农业学报》2000,13(3):117-120

近年来农资部门和植保部门出售的除草剂品种繁多,新药不断出现,有许多除草剂在大田作物和桑园中使用,这些除草剂农药对家蚕的毒性如何?笔者等近年来做了大田常用除草剂农药对家蚕的毒性试验,本文报道8种除草剂对家蚕的触杀毒力、安全间隔期及中毒症状,以便为蚕农科学用药提供依据。 1 材料与方法 1.1 供试农药 市售41%农达水剂(美国孟山都公司),72%2,4－D丁酯水剂(河北万全农药厂),盖草能(中国农业生产资料集团公司分装),2%使它隆乳油(美国陶氏益农公司),20%克无踪水溶液(英国卜内门化学工业有限公司),50%高特克悬浮剂(德国艾格福公司),50%扑草劲可湿性粉剂(昆明农药厂)和10%新代力可湿性粉剂(浙江省乐清市乐吉化工厂)共8种。 1.2 供试蚕品种 春季781×782*734,秋季苏3*秋3×苏4*苏12,由省农科院蚕研所春用组提供。 1.3 试验地点及桑品种 在本所生理病理室和桑树研究室进行,6年生油桑品种,低干养成,7500株／ha  相似文献   

Effect of Dimethyl Sulfoxide on Cell Cycle Synchronization of Goldfish Caudal Fin Derived Fibroblasts Cells     

CH Choresca  OJ Koo  SG Hong  HJ Oh  DK Gomez  JH Kim  BC Lee  SC Park 《Reproduction in domestic animals》2010,45(5):e73-e77

Several studies have previously been conducted regarding cell cycle synchronization in mammalian somatic cells. However, limited work has been performed on the control of cell cycle stages in the somatic cells of fish. The aim of this study was to determine the cell cycle arresting effects of several dimethyl sulfoxide (DMSO) concentrations for different times on different cell cycle stages of goldfish caudal fin‐derived fibroblasts. Results demonstrated that the cycling cells or control group (68.29%) yields significantly higher (p < 0.05) arrest in G0/G1 phase compared with the group treated for 24 h with different concentrations (0.5%, 1.0% or 1.5%) of DMSO (64.88%, 65.70%, 64.22% respectively). The cell cycle synchronization in the treatment of cells with 1.0% DMSO at 48 h (81.14%) was significantly higher than that in the groups treated for 24 h (76.82%) and the control group (77.90%). Observations showed that treatment of DMSO resulted in an increase in the proportion of cells at G0/G1 phase for 48 h of culture. However, high levels of apoptotic cells can be detected after 48 h of culture treated with 1% concentration of DMSO.  相似文献   

LONG‐TERM MANURING AND FERTILIZER EFFECTS ON DEPLETION OF SOIL ORGANIC CARBON STOCKS UNDER PEARL MILLET‐CLUSTER BEAN‐CASTOR ROTATION IN WESTERN INDIA     

CH. Srinivasarao  B. Venkateswarlu  R. Lal  A. K. Singh  S. Kundu  K. P. R. Vittal  J. J. Patel  M. M. Patel 《Land Degradation \u0026amp; Development》2014,25(2):173-183

Soil organic carbon (SOC) pools are important for maintaining soil productivity and reducing the net CO₂ loading of the atmosphere. An 18‐year old long‐term field experiment involving pearl millet‐cluster bean‐castor sequence was conducted on an Entisol in western India to examine the effects of chemical fertilizers and manuring on carbon pools in relation to crop productivity and C sequestration. The data showed that even the addition of 33.5 Mg ha⁻¹ C inputs through crop residues as well as farm yard manure could not compensate the SOC depletion by oxidation and resulted in the net loss of 4.4 Mg C ha⁻¹ in 18 years. The loss of SOC stock in the control was 12 Mg C ha⁻¹. Conjunctive use of chemical fertilizers along with farm yard manure produced higher agronomic yields and reduced the rate of SOC depletion. The higher average seed yields of pearl millet (809 kg ha⁻¹), cluster bean (576), and castor (827) over six cropping seasons were obtained through integrated use of fertilizers and manure. For every Mg increase in profile SOC stock, there was an overall increase of 0.46 Mg of crop yield, comprising increase in individual yield of pearl millet (0.17 Mg ha⁻¹ y⁻¹ Mg⁻¹ SOC), cluster bean (0.14) and castor (0.15). The magnitude of SOC build up was proportional to the C inputs. Carbon pools were significantly correlated with SOC, which increased with application of organic amendments. Threshold C input of 3.3 Mg C ha⁻¹ y⁻¹ was needed to maintain the SOC stock even at the low antecedent level. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Dr. Atwood C. Asbury     

Sara K. Lyle 《Journal of Equine Veterinary Science》2014

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