A modified critical test and its use in two dose titration trials to assess efficacy of praziquantel for Anoplocephala perfoliata in equids     

Slocombe JO 《Veterinary parasitology》2006,136(2):127-135

Aims of this study with 43 equids naturally infected with Anoplocephala perfoliata in two dose titration trials were to document (i) the usefulness of a critical test with a 48 h treatment to necropsy period, (ii) efficacy of an oral paste of 0.5-2.0 mg praziquantel/kg body weight, and (iii) when after treatment would fecal egg counts provide best estimates of the tapeworm's prevalence in a herd. All feces passed by an equid after treatment and collected in successive 12 h batches were examined for tapeworms. At necropsy, tapeworms were identified as attached to the mucosa or unattached. Tapeworms were examined with a stereoscope and identified as normal or abnormal. Fecal samples were taken for egg counts at treatment and at 6 h intervals thereafter. In 32 of 36 treated equids, efficacy was 100% and mean efficacies for 0.5, 1.0, 1.5 and 2.0 mg praziquantel/kg body weight were 85.5, 99.7, 100 and 100%, respectively. Two equids treated with 0.5 mg praziquantel/kg body weight had low efficacies (5.4 and 38.1%) and normal tapeworms were found attached in the ventral colon and in one equid also in the dorsal colon. In seven untreated equids, tapeworms were primarily in the cecum with 21.3% detached. "Major fragments" or worms without a scolex but otherwise nearly a complete worm were 20.5% of the number of intact worms; they were not included in the efficacy analysis but should be. If the two equids with low efficacy were eliminated and if the number of all tapeworms and major fragments are combined less than 0.5% were in feces within 12 h of treatment, about 20% were in the 12-24 h period, 42% in 24-36h, 24% in 36-48 h and 13.5% in the equids at necropsy. One horse passed all its tapeworms in 24 h. This 48 h test when compared with a 24 h one with no examination of feces was more efficient in use of trial animals and reduced underestimation and overestimation of efficacy. However, a protocol similar to the 48 h test but with a 24 or 36 h post-treatment period should be investigated. The mean egg count peaked 18-24 h after treatment and samples taken at that time would provide the best estimate of prevalence. The Cornell-Wisconsin centrifugal flotation technique had a specificity of 100% and at 18 and 24 h its sensitivity was 94%. A brief discussion on critical and controlled tests for assessing efficacy of an anthelmintic for A. perfoliata is presented.  相似文献   

Influence of sulfometuron methyl on conifer seedling root development     

Owen T. Burney  Douglass F. Jacobs 《New Forests》2009,37(1):85-97

On three sites in coastal northwestern Oregon, USA, seedling root and shoot development were assessed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western red-cedar (Thuja plicata Donn ex D. Don) container seedlings under varying sulfometuron methyl (Oust XP^®) herbicide application treatments. Treatments consisted of application of 0.16 kg active ingredient (ai) ha^?1 as a site preparation in fall 2003, a release application in fall 2004, or a control treatment with no application. Seedlings were planted in winter 2004 and measurements recorded in summer 2004, winter 2005, and summer 2005. During first season growth, western red-cedar seedlings showed the greatest negative impact to site preparation compared to the control with overall average new root length outside the root plug reduced by 67%. Significant reductions in root length also occurred for western hemlock (47%) and Douglas-fir (40%) seedlings. About 9 months after the release treatment, and 21 months after the site preparation application, there were no significant differences between treatments for any measured parameter. These findings suggest that seedlings under the site preparation treatment recovered from initial damage incurred to the root system. Lack of seedling response under the release treatment may be the result of opposing influences from the herbicide application associated with seedling phytotoxicity and enhanced seedling development resulting from effective vegetation control. Although our study was limited to 21 months following planting, reduced vegetation cover in the site preparation and release treatments suggests that these treatments may benefit future seedling growth.  相似文献   

Potassium carryover dynamics and optimal application policies in cotton production     

David C. Harper  James A. Larson  C. Owen Gwathmey 《Agricultural Systems》2012,106(1):84-93

Information about soil nutrient carryover dynamics can assist cotton producers with the optimal management of potassium (K) fertilizer. Optimal K management promotes cotton plant health, may decrease input costs, and increases cotton lint yields. A dynamic programming model was developed to determine optimal K application rates and economic returns under different soil information scenarios based on cotton yield response to K fertilizer and fertilizer carryover estimates from a multi-year field trial. A Monte Carlo analysis was conducted to simulate the impact of stochastic input and lint prices and cotton yield on K management over a five-period planning horizon. Results suggest that soil test data could provide important information about K carryover potential, which may lead to more efficient fertilizer use and higher profit margins for cotton producers.  相似文献   

Enhanced atrazine degradation is widespread across the United States          下载免费PDF全文

Thomas C Mueller  Ethan T Parker  Larry Steckel  Sharon A Clay  Micheal DK Owen  William S Curran  Randall Currie  Robert Scott  Christy Sprague  Daniel O Stephenson  Donnie K Miller  Eric P Prostko  W James Grichar  James Martin  L Jason Kruz  Kevin Bradley  Mark L Bernards  Peter Dotray  Stevan Knezevic  Vince Davis  Robert Klein 《Pest management science》2017,73(9):1953-1961

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Contextual influences on animal decision‐making: Significance for behavior‐based wildlife conservation and management          下载免费PDF全文

Megan A. OWEN  Ronald R. SWAISGOOD  Daniel T. BLUMSTEIN 《Integrative zoology》2017,12(1):32-48

Survival and successful reproduction require animals to make critical decisions amidst a naturally dynamic environmental and social background (i.e. “context”). However, human activities have pervasively, and rapidly, extended contextual variation into evolutionarily novel territory, potentially rendering evolved animal decision‐making mechanisms and strategies maladaptive. We suggest that explicitly focusing on animal decision‐making (ADM), by integrating and applying findings from studies of sensory ecology, cognitive psychology, behavioral economics and eco‐evolutionary strategies, may enhance our understanding of, and our ability to predict how, human‐driven changes in the environment and population demography will influence animal populations. Fundamentally, the decisions animals make involve evolved mechanisms, and behaviors emerge from the combined action of sensory integration, cognitive mechanisms and strategic rules of thumb, and any of these processes may have a disproportionate influence on behavior. Although there is extensive literature exploring ADM, it generally reflects a canalized, discipline‐specific approach that lacks a unified conceptual framework. As a result, there has been limited application of ADM theory and research findings into predictive models that can enhance management outcomes, even though it is likely that the relative resilience of species to rapid environmental change is fundamentally a result of how ADM is linked to contextual variation. Here, we focus on how context influences ADM, and highlight ideas and results that may be most applicable to conservation biology.  相似文献   

Research Support Services in Agriculture at Clemson University: Survey Results From Faculty With Implications for Library Services     

Megan Sheffield 《Journal Of Agricultural & Food Information》2017,18(3-4):189-199

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E7 (1057ΔTA) mutation of the acidic α‐glucosidase gene causes Pompe's disease in Droughtmaster cattle          下载免费PDF全文

RE Lyons  DJ Johnston  MR McGowan  A Laing  B Robinson  H Owen  BD Hill  BM Burns 《Australian veterinary journal》2017,95(5):138-142

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Selecting cotton yield response function to estimate profit-maximizing potassium fertilization rates for cotton production in Tennessee     

Xavier Harmon  Christopher N. Boyer  C. Owen Gwathmey  James A. Larson  Roland K. Roberts 《Journal of plant nutrition》2017,40(11):1547-1556

Recent research has shown that stochastic yield response functions fit data better than deterministic yield response functions; however, little research exists comparing profit-maximizing fertilizer rates for upland cotton (Gossypium hirsutum L.) using stochastic and deterministic yield response functions. The objective of this research was to determine the most appropriate yield response functional form from which to determine the profit-maximizing potassium (K) rate for cotton in Tennessee. Data were used from a nine-year K fertilizer experiment in Jackson, Tennessee. Quadratic, quadratic-plus-plateau, linear response plateau, and linear response stochastic plateau response functions were estimated to determine the yield response function that best fit the data. The linear response stochastic plateau function was the most suitable yield response function for the data. The profit-maximizing K rate ranged from 65.2 to 74.3 kg K ha^?1. Misspecification of the yield response function recommended over-application of K fertilizer and decreased the producer's short-term profits.  相似文献   

Factors affecting the efficiency of aerosolized salbutamol delivery via a metered dose inhaler and equine spacer device          下载免费PDF全文

R. S. Pirie  B. C. McGorum  C. Owen  O. Carr  H. Oakley  G. McLachlan 《Journal of veterinary pharmacology and therapeutics》2017,40(3):231-238

Despite frequent use of metered dose inhalers (MDIs) and spacers in equine practice, limited information exists on the efficiency of aerosol delivery using such devices. We determined the particle size distribution within an MDI‐generated salbutamol aerosol delivered via an equine spacer using ‘best practice’ delivery technique and assessed the effect of variations in MDI use technique (shaking prior to each actuation, rapid repetitive actuations, and MDI angulation) on aerosol delivery efficiency. Under optimal conditions, only 53(±18) μg salbutamol per 100 μg actuation was delivered beyond the spacer. Although this aerosol had a high [89.6% (±2.4)] fine particle (<5 μm) fraction, and a low mass median aerodynamic diameter [2.52 (±0.29) μm], and particle size variability [geometric SD – 1.66 (±0.16) μm], within all particle size fractions, there was a high coefficient of variance (31–79%) of the percentage salbutamol delivered between experimental runs, thus impeding any effort to predict drug delivery to the patient during equine inhalation therapy. Despite observable trends and with the exception of minor statistically significant changes in the least abundant particle sizes, none of the deviations from a ‘best practice’ delivery technique significantly altered the relative salbutamol delivery beyond the spacer, a finding which has potential relevance with regard to maintaining user compliance.  相似文献   

Fournier's gangrene in a cat     

Danielle E. Berube  DVM  ; Megan F. Whelan  DVM  DACVECC  ; Kathy C. Tater  DVM  DACVD    Kiko E. Bracker  DVM  DACVECC 《Journal of Veterinary Emergency and Critical Care》2010,20(1):148-154

Objective – To describe the clinical course of a cat diagnosed with Fournier's gangrene.
Case Summary – A 2-year-old castrated male cat was presented to an emergency hospital for evaluation of acute onset of lethargy, mucoid anal discharge, and fever. During hospitalization, with provision of supportive care, an area of necrotizing fasciitis around the prepuce and anus developed and surgical debridement was performed. Severe sepsis developed secondary to the necrotizing fasciitis and the cat was eventually euthanized.
New Information Provided – The purpose of this report is to document the first case of Fournier's gangrene in a cat that presented for mucoid anal discharge, lethargy, and mild ataxia, and to alert emergency clinicians to this disease process. Early detection of the disease with prompt, aggressive supportive care and surgical debridement is necessary for successful treatment.  相似文献