排序方式： 共有28条查询结果，搜索用时 15 毫秒
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Taylor JD Fulton RW Lehenbauer TW Step DL Confer AW 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(12):1351-1359
Bovine respiratory disease (BRD) is the most common and costly disease of beef cattle in North America. Despite extensive research, industry practices are often more informed by dogma than by fact. Frequently advocated interventions, including vaccination, various processing procedures, and nutritional manipulation, have limited impact on morbidity and mortality. Evidence for use of oral antimicrobials, either in feed or water, appears to be equivocal. In contrast, preconditioning and metaphylaxis have significant scientific evidence of efficacy, with weaning prior to sale potentially being the most important component of preconditioning. The inability to reach more definitive conclusions in preventing BRD may be attributable to difficulties in investigating the disease. Study challenges include potential for extensive confounding, tremendous variability, the multi-factorial nature of the disease, and inadequate methods for diagnosis. 相似文献
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Kiyokazu Murai Terry W. Lehenbauer John D. Champagne Kathy Glenn Sharif S. Aly 《Preventive veterinary medicine》2014
Diagnostic strategies to detect contagious mastitis caused by Mycoplasma bovis, Staphylococcus aureus, and Streptococcus agalactiae in dairy herds during an outbreak have been minimally studied with regard to cost and diagnostic sensitivity. The objective of this cross-sectional study was to compare the cost-effectiveness of diagnostic strategies for identification of infected cows in two California dairy herds during contagious mastitis outbreaks. 相似文献
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TW Jordan 《New Zealand veterinary journal》2020,68(4):203-213
ABSTRACTThe fungal metabolite sporidesmin is responsible for the hepatogenous photosensitising disease facial eczema in livestock. Toxicity is due to a sulfur-bridged epidithiodioxopiperazine ring that has wide biological reactivity. The ways in which the toxin causes hepatobiliary and other tissue damage have not been established. Hypotheses include direct interaction with cellular thiols including protein cysteine residues or production of reactive oxygen species resulting in oxidative stress. Comparison with the cellular effects of the structurally related compound gliotoxin suggests additional mechanisms including interaction with cell adhesion complexes and possible downstream consequences for regulated necrosis as a response to tissue injury. Revision of hypotheses of how sporidesmin affects cells has the potential to generate new strategies for control of facial eczema including through identification of proteins and genes that are associated with resistance to the disease. 相似文献
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A Hoffman J Wolfer L Occelli TW Lehenbauer J Sapienza JM Novak KL Combs KA Konrade 《American journal of veterinary research》2012,73(8):1299-1304
Objective-To evaluate the refractive error induced by intraocular administration of silicone oil (SiO) in dogs. Animals-47 client-owned dogs evaluated for blindness secondary to retinal detachment. Procedures-3-port pars plana vitrectomy with perfluoro-octane and SiO exchange (1,000- or 5,000-centistoke SiO) was performed in 1 or both eyes for all dogs (n = 63 eyes), depending on which eye or eyes were affected. Dogs were normotensive, had complete oil filling of the eyes, and were examined in a standing position for retinoscopic examination of both eyes (including healthy eyes). Results-The mean refractive error for SiO-filled phakic and pseudophakic eyes was 2.67 and 3.24 D, respectively. The mean refractive error for SiO-filled aphakic eyes was 6.50 D. Dogs in which 5,000-centistoke SiO was used had consistently greater positive refractive errors (mean, 3.45 D), compared with dogs in which 1,000-centistoke SiO was used (mean, 2.10 D); however, the difference was nonsignificant. There was no significant linear relationship between refractive error and the number of days between surgery and retinoscopy. Conclusions and Clinical Relevance-Hyperopia was observed in all dogs that underwent SiO tamponade, regardless of lens status (phakic, pseudophakic, or aphakic). Aphakic eyes underwent a myopic shift when filled with SiO. Pseudophakic eyes appeared to be more hyperopic than phakic eyes when filled with SiO; however, additional investigation is needed to confirm the study findings. 相似文献
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Kevin E. Washburn Robert N. Streeter Jeremiah T. Saliki Terry W. Lehenbauer 《Canadian journal of veterinary research》2004,68(2):105-111
The objectives of this study were to determine the optimal concentration of phenothiazine dye required to inactivate bovine viral diarrhea virus (BVDV) in goat colostrum following 60 min of illumination and determine if immunoglobulin concentration is affected by this technique. In addition, the potential of continuous agitation of colostrum during illumination to affect viral kill was investigated. This experiment was designed to more closely approximate on-farm use than a previous pilot study performed by the same investigators. Bovine viral diarrhea virus was used as a model for caprine arthritis-encephalitis virus. Goat colostrum containing BVDV was illuminated for 60 min following the addition of either methylene blue (MB) or methylene violet (MV). Four different concentrations of each dye were evaluated. Illumination was performed in a small, portable chesttype freezer equipped on the inside with white fluorescent lights. Some samples were continuously rocked during illumination, while others remained stationary. Virus levels were determined before and after illumination. Immunoglobulin concentrations were determined for time 0 and 60 min. One μM MB reduced virus to undetectable levels following 60 min of illumination. A concentration of 20 μM MV was required to reduce virus levels to zero. Agitation of colostrum samples had no effect with either MB or MV on whether virus levels were reduced. High concentrations of MB and MV had no important effect on immunoglobulin concentrations. 相似文献
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JW Schlipf Jr K Eaton P Fulkerson TW Riebold C Cebra 《Veterinary anaesthesia and analgesia》2005,32(4):7-8
Ketamine is a rapid acting, potent, nonspecific, noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist commonly used for inducing general anesthesia and for providing post-operative pain management and may possibly lessen the need for other potentially harmful or contraindicated analgesics in camelids, such as nonsteroidal anti-inflammatory drugs. Prior to determining the effectiveness of CRI ketamine for analgesia, a safe, sub-anesthetic dose was established that did not produce untoward side effects, sedation or alter normal behavior. Six healthy male alpacas (40–90 kg) were used for the trial and each acted as its own control. Each alpaca was randomly assigned to receive ketamine at 20 and 40 μg kg–1 minute–1 in 500 mL saline. A blinded observer recorded heart rate, respiratory rate, and body temperature hourly, and behavior for 8 hours. There was a 72-hour washout period between each dosing regime. An equal volume saline CRI without ketamine was used as a control. Each alpaca was allowed a one-week washout prior to being anesthetized with isoflurane using mask induction. After achieving a stable plane of anesthesia, the MAC value for isoflurane was determined. Ketamine was infused at 40 μg kg–1 pre-existing pain is unknown, but for elective procedures, preemptive analgesia using ketamine CRI in alpacas may be beneficial. 相似文献
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R J Panciera S A Ewing J S Mathew T W Lehenbauer C A Cummings J P Woods 《Veterinary parasitology》1999,82(4):261-272
We report previously undescribed, early lesions in skeletal muscle of dogs experimentally infected with Hepatozoon americanum by ingestion of laboratory-reared, infected Amblyomma maculatum. The earliest muscle lesion was recognized at the first interval of examination 3 weeks following exposure. The lesion consisted of a large, modified host cell whose cytoplasm frequently contained a demonstrable parasite. In skeletal muscle, the cell was consistently located between muscle fibers or in loose connective tissue adjacent to those fibers. Evidence suggesting that the parasite arrives in muscle and other tissue within the host cell cytoplasm is presented. Mucopolysaccharide encystment of the host cell, absent at this early stage, was acquired gradually and approached maximal development 26 weeks post exposure. Completion of the asexual cycle as evidenced by the presence of parasites entering vascular lumens within granulomas and also by the presence of gamonts in peripheral blood leukocytes, occurred within 28-32 days postexposure. Progression of the parasite cycle from meront to passage of zoites into vessel lumens of granulomas can occur in 11 or fewer days. The density with which parasitic lesions occur in one named skeletal muscle compared to other named muscles, although somewhat variable, was not significantly different in either experimentally induced or natural infections. The distribution of developmental stages of the parasite/lesion in four experimental infections (969 lesions) is compared with those in eight dogs with natural infections (557 lesions). 相似文献
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R Cauble Da Silva LB TW Barbee P Celliers C Decker RA London JC Moreno JE Trebes AS Wan F Weber 《Science (New York, N.Y.)》1996,273(5278):1093-1096
X-ray lasers (XRLs) have experimental average gains that are significantly less than calculated values and a persistently low level of spatial coherence. An XRL has been used both as an injected signal to a short XRL amplifier and as an interferometer beam to measure two-dimensional local gain and density profiles of the XRL plasma with a resolution near 1 micrometer. The measured local gain is in agreement with atomic models but is unexpectedly spatially inhomogeneous. This inhomogeneity is responsible for the low level of spatial coherence observed and helps explain the disparity between observed and simulated gains. 相似文献