Evaluation of the efficacy of tulathromycin as a metaphylactic antimicrobial in feedlot calves     

Booker CW  Abutarbush SM  Schunicht OC  Jim GK  Perrett T  Wildman BK  Guichon PT  Pittman TJ  Jones C  Pollock CM 《Veterinary therapeutics : research in applied veterinary medicine》2007,8(3):183-200

The purpose of this study was to determine the efficacy and cost-effectiveness of tulathromycin (DRAX) versus tilmicosin (MIC) or oxytetracycline (TET) as a metaphylactic antimicrobial in feedlot calves. Calves that received DRAX had significantly (P<.05) lower initial undifferentiated fever (UF) treatment and relapse rates; lower overall chronicity, overall mortality, and cause-specific mortality rates; higher average daily gains; and improved quality grades. However, calves that received DRAX also had poorer (P<.05) yield grades compared with calves that received MIC or TET and worse feed conversion compared with calves that received MIC. Net advantages in the DRAX group were 3.79CanDollars/animal and 16.96CanDollars/animal compared with the MIC and TET groups, respectively. Based on these results, DRAX is a more efficacious and cost-effective metaphylactic antimicrobial than MIC or TET in feedlot calves at ultra-high risk of developing UF. In addition, this study presents a comparison between two methods ("deads out" and "deads in") of calculating feedlot performance variables.  相似文献   

A hydraulic press for extracting fluids from plant tissue samples     

Calvin H. Pearson  Donna J. Rath 《Industrial Crops and Products》2009,29(2-3):634-637

In the past, pressing fluids from ground plant matter has typically been accomplished with a hand press. Fluids must be separated from dry matter as part of the methodology for various applications in plant species including latex quantification. This article describes the design and construction of a hydraulic press used for extracting fluids from plant tissue samples, the accompanying press plates, sieve vessels, and collection pan, and the process we use for pressing plant fluids from sunflower (Helianthus annuus) homogenate. The overall height of the press is 205.7 cm (81 in.) and the width is 94.0 cm (37 in.). We have used the press for several years and have not identified any flaws in its design and performance. While designed and constructed for use in latex extraction we envision the press and associated press plates, sieve vessels, and collection pan could be used in a variety of other applications.  相似文献   

Immunodeficiency associated with multiple concurrent infections in captive Pallas' cats (Otocolobus manul).     

Cornelia J Ketz-Riley  Jerry W Ritchey  John P Hoover  Calvin M Johnson  Michael T Barrie 《Journal of zoo and wildlife medicine》2003,34(3):239-245

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The Dark Reductions of Photosynthesis     

Benson A  Calvin M 《Science (New York, N.Y.)》1947,105(2738):648-649

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WILLIAM SPENCER CARTER 1869-1944     

Hendrix BM  Porter EL  Calvin DB  Leake CD 《Science (New York, N.Y.)》1944,100(2586):42-43

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Lunar organic compounds: search and characterization     

Burlingame AL  Calvin M  Han J  Henderson W  Reed W  Simoneit BR 《Science (New York, N.Y.)》1970,167(3918):751-752

The carbon concentration in Apollo 11 lunar fine material is of the order of 200 ppm. By far the largest single amount of this carbon appears to be in carbon monoxide. Some of this seems to be in the form of gas bubbles in the glass spheres, but most of it could be in some complex form other than gas. This result would be consistent with the idea that most of the fines passed through a high temperature and that the carbon was oxidized by mineral oxides at that time.  相似文献   

Synaptic noise as a source of variability in the interval between action potentials   总被引：2，自引：0，他引：2  

W H Calvin  C F Stevens 《Science (New York, N.Y.)》1967,155(764):842-844

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Life in science. Ichthyologists hooked on Facebook     

Sidlauskas B  Bernard C  Bloom D  Bronaugh W  Clementson M  Vari RP 《Science (New York, N.Y.)》2011,332(6029):537

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Conceptual methodologies in agro-environmental systems   总被引：1，自引：0，他引：1  

Calvin W. Rose  Samuel Adiku 《Soil & Tillage Research》2001,58(3-4):141-149

When continuous measurement of relevant above- and below-ground environmental factors is made, and the dynamics of crop growth and phenology is followed, it is shown that small-plot agronomic experimentation can provide information vital to the development and testing of simulation models. Such models for crops of maize (Zea mays) and the legume cowpea (Vigna unguiculata), grown as sole crops and in an intercrop system, were used to simulate yield at two separate sites in the main savanna farming zones in Ghana, West Africa. Simulation was carried out for these three cropping systems using 20 years of historical rainfall data for the two sites, investigating the effect on yield of management options which included time of planting, rate of nitrogen fertilizer application, and crop planting density.

The yield results of this series of simulations were then subject to two different types of analysis in order to assist the evaluation of agricultural options for the nation. The first analysis was an economic evaluation based on gross margins, but using the stochastic-dominance technique to rank the profitability of the alternative cropping and management systems.

The second, more general methodology employed was multi-criteria analysis (MCA). This analysis covered economic returns and their variability, the amount and quality of residue returned to the soil, and the aerial cover provided by the crop. Other factors which could affect the sustainability of production in the long term, but which could only be evaluated qualitatively, were also included in the analysis, as allowed in MCA methodology. The MCA was then carried out for three scenarios in which different weightings were given to economic outcomes and to factors which are believed to encourage ecological sustainability. These scenarios allow recognition of different priorities which might be given by traditional subsistence farmers as compared to commercial producers.

Outcomes of this broad analysis of development alternatives provided scientific support for the traditional Ghanaian practice of grain/legume intercropping which is also widespread in the tropics. The suite of methodologies illustrated by the case study appears to be suitable for the evaluation of alternative farming systems at the scale of a small nation such as Ghana.  相似文献   

Gene expression profiling of avian macrophage activation     

Bliss TW  Dohms JE  Emara MG  Keeler CL 《Veterinary immunology and immunopathology》2005,105(3-4):289-299

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