Efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for the treatment of acute postpartum metritis in dairy cows     

Chenault JR  McAllister JF  Chester ST  Dame KJ  Kausche FM  Robb EJ 《Journal of the American Veterinary Medical Association》2004,224(10):1634-1639

OBJECTIVE: To evaluate the efficacy of ceftiofur hydrochloride sterile suspension administered parenterally for treatment of acute postpartum metritis (APM) in dairy cows. DESIGN: Multilocation, randomized block, field trial. ANIMALS: 406 cows in the first 14 days postpartum. PROCEDURE: Cows with rectal temperatures > or = 39.5 degrees C (103.1 degrees F) without clinical signs of respiratory or gastrointestinal tract disease and with a fetid vaginal discharge were allocated randomly in blocks of 3 to 3 treatment groups: sterile saline (0.9% NaCl) solution administered at a dosage of 2 mL/45.4 kg (2 mL/100 lb), SC or IM, once daily for 5 days (control); or ceftiofur hydrochloride administered at a dosage of 1.1 or 2.2 mg of ceftiofur equivalents (CE)/kg (0.5 or 1 mg/lb, respectively), SC or IM, once daily for 5 days. Cows were evaluated on days 6, 10, and 14, and clinical cure or failure to cure was determined. Clinical cure was defined as no additional antimicrobial treatment administered, rectal temperature < 39.5 degrees C, and absence of a fetid vaginal discharge. RESULTS: On day 14, clinical cure rates were 77%, 65%, and 62% for the 2.2 mg of CE/kg, 1.1 mg of CE/kg, and control groups, respectively. No significant differences were detected in clinical cure rates between control and treatment groups on day 10 or 6. CONCLUSIONS AND CLINICAL RELEVANCE: Ceftiofur hydrochloride administered at a dosage of 2.2 mg of CE/kg, SC or IM, once daily for 5 days was efficacious for treatment of APM in dairy cows.  相似文献   

Age-dependent induction of immunity and subsequent survival costs in males and females of a temperate damselfly     

Tonia Robb  Mark R Forbes 《BMC ecology》2006,6(1):15-13

Background  

To understand variation in resistance to parasites within host populations, researchers have examined conditions under which immunity is induced and/or is costly. Both host sex and age have been found to influence immune expression and subsequently are likely factors influencing the costs of resistance. The purpose of this study was to examine immune expression and associated survival costs for two age groups (newly emerged and sexually mature individuals) of the damselfly, Enallagma boreale Selys. Survival was assessed for experimentally challenged and control damselflies, housed initially at 22°C and then subjected to low temperatures (15°C) associated with reduced foraging activity and food deprivation. Experimental conditions emulated natural local variation in bouts of good weather followed by inclement weather (successions of days with hourly mean temperatures around 15°C and/or rainy weather).  相似文献   

Early vascular sporulation: a possible role in the virulence of Verticillium albo-atrum in wilt of alfalfa     

George Newcombe  Barbara Lee  Jane Robb   《Physiological and Molecular Plant Pathology》1990,36(6)

Serial subculturing of an alfalfa field isolate of Verticillium albo-atrum produced two variants which were significantly less virulent than the original. When conidia of the original isolate, stored at − 70 °C, were infused into alfalfa cuttings, the pathogen grew from spore trapping sites into contiguous vessels and began to sporulate within 24 h. The frequency of vessels in which sporulation occurred at 24 h was similar in alfalfa genotypes known to differ in disease ratings and in host resistance to lateral penetration of vessels. With conidia of the two variants as inoculum, hyphae were found to penetrate much more extensively from trapping ites into adjacent vessels by 24 h. However, the more virulent original isolate sporulated two to three times more frequently. An isolate of V. albo-atrum from potato, which was non-pathogenic to alfalfa, had limited lateral penetrating ability in alfalfa but never sporulated by 24 h in laterally penetrated vessels. Of parameters studied, including sporulation and radial growth, only early vascular sporulation in laterally penetrated vessels correlated with the greater virulence of the original alfalfa isolate.  相似文献   

Comparison of the use of regulatory assays and high-performance liquid chromatography for detection of residues of ceftiofur sodium metabolites in tissue specimens of culled dairy cattle     

Payne MA  Wetzlich SE  Robb EJ  Brown SA  Gardner IA  Cullor JS  Craigmill AL 《American journal of veterinary research》2004,65(12):1730-1733

OBJECTIVE: To compare the results of regulatory screening and confirmation assays with those of high-performance liquid chromatography (HPLC) in the detection of ceftiofur metabolites in the tissues of culled dairy cattle. ANIMALS: 17 lactating Holstein dairy cows. PROCEDURE: Daily IM injections of ceftiofur sodium were administered at a dose of 2.2 mg of ceftiofur equivalents/kg (n = 6) or 1.0 mg of ceftiofur equivalents/kg (10) for 5 days. Following withdrawal times of 12 hours (high-dose ceftiofur) and either 5 or 10 days (low-dose ceftiofur), cows were slaughtered and liver, kidney, and diaphragmatic muscle specimens were harvested and analyzed by HPLC and standard regulatory methods that included the following assays: the swab test on premises, the fast antimicrobial screen test, the calf antibiotic and sulfa test, and the 7-plate bioassay confirmation test. RESULTS: In all tissue specimens, residues of ceftiofur and desfuroylceftiofur-related metabolites, as measured by HPLC, were less than regulatory tolerance, as defined by the FDA. False-positive screening assay results were more likely for tissue specimens that had been frozen for shipment to a federal laboratory, compared with fresh tissue specimens that were assayed at the slaughter establishment (23% vs 3% false-positive results, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: The observation that fresh tissues had negative results on screening assays, whereas subsets of the same tissue specimens had false-positive results on screening assays following freezing, suggests that freezing and thawing interferes with microbial inhibition-based regulatory screening assays.  相似文献   

Dose determination and confirmation for ceftiofur crystalline-free acid administered in the posterior aspect of the ear for control and treatment of bovine respiratory disease     

Hibbard B  Robb EJ  Chester ST  Dame KJ  Moseley WW  Bryson WL 《Veterinary therapeutics : research in applied veterinary medicine》2002,3(1):22-30

Three studies were conducted to determine and confirm the effective dosage rate of ceftiofur crystalline-free acid sterile suspension (CCFA-SS, 200 mg ceftiofur equivalents [CE]/ml), a long-acting ceftiofur formulation, for control and treatment of bovine respiratory disease (BRD). In each study, CCFA-SS was administered once by subcutaneous (SC) injection in the middle third of the posterior aspect of the ear. Study 1 was conducted using an intratracheal challenge with Mannheimia (formerly Pasteurella) haemolytica and dosages ranging from 0 to 8.8 mg CE/kg to select a dosage for further field testing. In Study 2, a single dose of CCFA-SS at 0.0, 4.4, or 6.6 mg CE/kg was administered when uniform clinical signs of BRD were present in feedlot cattle. Study 3 was conducted in several feedlots to evaluate the efficacy, practicality, and safety of CCFA-SS at 4.4 or 6.6 mg CE/kg compared with a placebo control or tilmicosin for preemptive control of BRD. In Study 1, the effective dose was determined to be 5.35 mg CE/kg; therefore, 4.4 and 6.6 mg CE/kg were selected as the dosages for further field testing. Administration of CCFA-SS at 4.4 or 6.6 mg CE/kg improved treatment success compared with negative controls (P < or =.05 for both doses) in Study 2. In Study 3, a single administration of 4.4 or 6.6 mg CE/kg was comparable to tilmicosin (P <.001) and was significantly better than placebo (P <.001) for the control of BRD. Using the ear as an administration site was acceptable under field conditions and was well tolerated by all animals. These studies demonstrated that a single administration of CCFA-SS by SC injection in the middle third of the posterior aspect of the ear at 4.4 or 6.6 mg CE/kg is effective, safe, and practical for preemptive control and treatment of the bacterial component of BRD in feedlot cattle. Administration in an inedible tissue results in a short withdrawal time and no injection-site trimming at slaughter.  相似文献   

Mapping foodscapes and sagebrush morphotypes with unmanned aerial systems for multiple herbivores     

Olsoy  Peter J.  Forbey  Jennifer S.  Shipley  Lisa A.  Rachlow  Janet L.  Robb  Brecken C.  Nobler  Jordan D.  Thornton  Daniel H. 《Landscape Ecology》2020,35(4):921-936

Landscape Ecology - The amount and composition of phytochemicals in forage plants influences habitat quality for wild herbivores. However, evaluating forage quality at fine resolutions across broad...  相似文献   

Cyclosporin A binding to calmodulin: a possible site of action on T lymphocytes   总被引：14，自引：0，他引：14  

P M Colombani  A Robb  A D Hess 《Science (New York, N.Y.)》1985,228(4697):337-339

Cyclosporin A, a potent immunosuppressive agent, has been widely used to treat patients with solid organ transplants. Although its precise mechanism of action is unknown, it appears to inhibit subsets of T lymphocytes at an early stage in cell activation. Fluorescent, fully active derivatives of cyclosporin A and calmodulin, a protein that binds calcium and is therefore essential to normal cell function, were utilized to demonstrate that cyclosporin A binds to calmodulin. Flow cytometry showed that the calmodulin inhibitors R24571 and W-7 competitively inhibited binding of cyclosporin A to cloned T lymphocytes. Cyclosporin A inhibited the calmodulin-dependent activation of phosphodiesterase in a dose-dependent manner. Binding of cyclosporin A to calmodulin may prevent the latter's role in the activation of the second messengers and enzymes required for effective cell proliferation and function in the immune response.  相似文献   

Borrowing from biology     

Nazar RN  Robb EJ 《Science (New York, N.Y.)》2007,318(5850):565

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Multiplanar quantitative computed tomography for bone mineral analysis in dogs     

M D Markel  R L Morin  M A Wikenheiser  R A Robb  E Y Chao 《American journal of veterinary research》1991,52(9):1479-1483

The purpose of this study was to determine the precision and accuracy of quantitative computed tomography bone mineral analysis in dogs in coronally reconstructed images. Nonhomogeneous tissues, such as bones with fractures or deformities, may be better analyzed if multiplanar reconstruction of the transaxial data could be performed without degradation of information. Our analysis demonstrated that coronal reconstruction of quantitative-computed tomography data was precise (1.2 to 4.7%) and accurate (1.3 to 7.5%) in vitro. The technique displays high-quality images, which can be analyzed at any location within the volume scanned. Quantitative computed tomography of canine osteotomy healing in vivo accurately determined bone mineral density of selected regions of interest. Bone mineral density correlated highly with calcium content of the tissue (R2 = 0.76, P less than 0.0001).  相似文献   

Efficacy of tulathromycin or enrofloxacin for initial treatment of naturally occurring bovine respiratory disease in feeder calves   总被引：3，自引：0，他引：3  

Robb EJ  Tucker CM  Corley L  Bryson WL  Rogers KC  Sturgess K  Bade DJ  Brodersen B 《Veterinary therapeutics : research in applied veterinary medicine》2007,8(2):127-135

After undergoing arrival processing at one of two commercial feedlots, feeder calves with clinical signs of bovine respiratory disease (BRD) were randomly assigned to receive either tulathromycin (2.4 mg/kg SC) or enrofloxacin (12.5 mg/kg SC). Additional therapy for calves that did not respond to initial treatment followed a prescribed course. Initial treatment with tulathromycin resulted in significantly higher (P = .009 and P = .031 at sites 1 and 2, respectively) therapeutic success (87.9% and 80%, respectively) than did initial treatment with enrofloxacin (70.2% and 62.5%, respectively). Animals treated with tulathromycin also had fewer subsequent treatments and higher weight gains compared with those treated with enrofloxacin.  相似文献