Plasma/muscle ratios of sulfadimethoxine residues in channel catfish (Ictalurus punctatus)     

C.C. WALKER  R.L. THUNE†  S.A. BARKER 《Journal of veterinary pharmacology and therapeutics》1995,18(4):306-310

Channel catfish ( n = 84) maintained at a water temperature of 27°C were used in a feeding study to determine the plasma to muscle concentration ratios of sulfadimethoxine (SDM) and 4-N-acetylsulfadimethoxine residues. Sulfadimethoxine medicated feed was provided free choice at 42 mg SDM/kg body weight once daily for 5 days and the plasma and muscle concentrations of SDM were determined at selected withdrawal times (6, 12, 24, 48, 72, and 96 hours) following the last dose. Considerable variation in total SDM tissue concentration among fish within a sampling period was observed. For fish ( n = 12) at six hours post-dose, total SDM concentrations ranged from 1.4–24.8 μg/mL and 0.6–12.6 μg/g, with mean total SDM concentrations of 9.1 μg/mL and 5.3 μg/g for plasma and muscle, respectively. However, a mean plasma:muscle concentration ratio of 1.8:1 ± 0.3:1 was obtained over all concentrations and sampling periods. The plasma:muscle 95% t distribution interval for individual fish was 1.2:1 to 2.4:1. A correlation coefficient of 0.967 was obtained for the relationship between plasma and muscle total SDM concentration among individual fish ( n = 25). Results of this study indicate that plasma total SDM concentration may be used to identify samples containing violative SDM muscle residue. No fish contained total SDM muscle residues greater than the FDA tolerance (0.1 μg/g) by 48 hours following the final dose.  相似文献   

A study of real-time ultrasonography for predicting ovine foetal growth under field conditions     

D O KLEEMANN  D H SMITH  S K WALKER  R F SEAMARK 《Australian veterinary journal》1987,64(11):352-353

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Dieldrin toxicity in housed Merino sheep     

J. R. W. GLASTONBURY  R. I. WALKER  D. J. KENNEDY  P. A. GILL  K. W. McDOUGALL†  A. G. SHARROCK‡ 《Australian veterinary journal》1987,64(5):145-148

An outbreak of nervous disease with deaths and reproductive failure was investigated in a fully housed flock of 640 super fine wool (Sharlea) Merino sheep. During the 4 months after the flock was dipped in dieldrin, 70 adult sheep died and no live lambs were produced by the ewes. The diagnosis of poisoning with dieldrin was based upon the presence of characteristic clinical signs, pathological findings and the detection of residues of dieldrin in tissues. Deficiency of vitamin A was confirmed in 2 sheep and may have contributed to the reproductive failure.  相似文献   

Protection against ovine footrot using a topical preparation of zinc sulphate     

DJ MARSHALL  RI WALKER  RE COVENY 《Australian veterinary journal》1991,68(5):186-188

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Biology of Commelina benghalensis L. in south-eastern Queensland. 1. Growth, development and seed production   总被引：2，自引：0，他引：2  

S. R. WALKER  J. P. EVENSON 《Weed Research》1985,25(4):239-244

Experiments conducted at Kingaroy in southeastern Queensland, investigated growth, development and seed production of Commelina benghalensis L. a weed of field crops, which produces aerial and underground flowers. Plants were grown from four seed types (large and small seeds from the two types of flowers) in pots exposed to the weather and in the field. Development was faster, and growth and seed production were greater in the field than in pots. Plants grown from aerial seeds were smaller, developed aerial flowers earlier, and produced more aerial fruits than plants grown from underground seeds. Rhizomes and underground flowers began to develop 6 weeks after emergence on plants from all seed types, prior to the development of aerial flowers. Seed production in the field was 8000 m^?2 for plants grown from underground seeds and 12000 m^?2 for plants grown from aerial seeds. Small aerial seeds represented 73–79% of the total seed production, large aerial seeds 19–22%, and underground seeds only 1–3%.  相似文献   

Copper toxicity in sheep fed oil palm by-products     

KF CHOOI  RI HUTAGALUNG  WE WAN MOHAMED 《Australian veterinary journal》1988,65(5):156-157

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EWRS Herbicide-Soil Working Group: Collaborative experiment on simazine persistence in soil     

A. WALKER  R. J. HANCE  J. G. ALLEN  G. G. BRIGGS  YUH-LIN CHEN  J. D. GAYNOR  E. J. HOGUE  A. MALQUORI  K. MOODY  J. R. MOYER  W. PESTEMER  A. RAHMAN  A. E. SMITH  J. C. STREIBIG  N. T. L. TORSTENSSON  L. S. WIDYANTO  R. ZANDVOORT 《Weed Research》1983,23(6):373-383

The effects of soil temperature and soil moisture content on the rate of simazine degradation were measured in the laboratory in soils from sixteen sites located in several different countries. First-order half-lives under standard incubation conditions were significantly correlated with clay content, organic carbon content and soil pH in a multiple linear regression. The temperature dependence of degradation was similar in the different soils whereas the moisture dependence showed considerable variation between soils. Persistence of simazine was also measured in the same soils in the field and at live additional sites. Weather records from the different sites for the periods of the Held experiments were used in conjunction with constants derived from the laboratory data in a computer program to simulate persistence in the field. In general, the model overestimated residues in the field. About half of the calculated residues were within 25% of those observed, an accuracy sufficient for practical purposes, but on several occasions the discrepancies between calculated and observed residues were greater than 50%. Possible reasons for the discrepancies and requirements for further experiments are discussed.  相似文献   

Aspects of the selective phytotoxicity of methazole. HI. Behaviour in plants following foliar treatment     

JULI E VERITY  ALLAN WALKER  DONALD S.H. DRENNAN† 《Weed Research》1981,21(6):317-324

Absorption of methazole by leaves of onion (Allium cepa), Stellaria media, Matricaria matricarioides and Veronica persica was rapid for the first 24 h after treatment and continued at a slower rate for up to 6 days to reach a maximum of between 35 and 60% of the amount applied. Differences in absorption between species were generally small. Absorption by the cotyledon of onion was greater than absorption into true leaves. Methazole on the leaf surface degraded to 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and small amounts of this degraded to 3-(3,4-dichlorophenyl) urea (DCPU). Methazole absorbed into leaves was relatively stable in M. matricarioides and DCPMU accumulated slowly. The rate of degradation was more rapid in the cotyledons than in the true leaves. Both in leaves and in cotyledons of onion and S. media, methazole degraded rapidly to DCPMU and this accumulated; in those of V. persica, DCPMU was degraded quickly to DCPU and unidentified products. The amount of DCPMU accumulated in the shoots was broadly correlated with the relative phytotoxicity of methazole to the different species, except for young seedlings of V. persica which contained no DCPMU but were susceptible to methazole.  相似文献   

The Relation between Infestation by Lepidopterous Stem Borers and Yield in Maize: Methods and Results¹     

P.T. WALKER 《EPPO Bulletin》1981,11(2):101-106

Decisions on the control of stem borers are based on the relation between yield and infestation rate. The latter is measured as the percentage of plants attacked, the degree of leaf attack, internode attack, stem breakage, or the number of eggs, larvae and pupae per stem or adults per trap. Methods used for the assessment of Ostrinia nubilalis, Sesamia nonagrioides, S. cretica, S. nonagrioides subsp. botanephaga, Chilo partellus and Busseola fusca are reviewed. The relation to crop loss can be measured by using natural infestations, insecticides, artificial infestation or prevention of attack, resistant varieties or by artificial simulation of attack. The advantages of these methods are discussed.  相似文献   

Granulocytopaenia and thrombocytopaenia in cattle     

T. J. NICHOLLS  M. J. SHIEL  H. A. WESTBURY  D. M. WALKER 《Australian veterinary journal》1985,62(2):67-68

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