Evaluation of a high-throughput nucleic acid extraction method for the detection of Mycobacterium avium subsp. paratuberculosis in bovine fecal samples by PCR     

Nagaraja R. Thirumalapura  Willard Feria  Eric Hue  Corey Zellers  Deepanker Tewari 《Journal of veterinary diagnostic investigation》2021,33(2):375

Johne’s disease (paratuberculosis) is an economically important disease of cattle worldwide. The disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), a fastidious gram-positive bacterium. PCR is increasingly used in diagnostic laboratories for the detection of MAP in fecal samples given the rapid test turnaround time and sensitivity and specificity comparable to fecal culture. However, efficient extraction of DNA for sensitive detection of MAP by PCR is affected by the complex lipid-rich cell wall of MAP and the presence of PCR inhibitors in feces. We evaluated a high-throughput nucleic acid extraction method (MagMAX core nucleic acid purification kit with mechanical lysis module) in conjunction with an hspX gene PCR for the detection of MAP from bovine fecal samples, which resulted in correct identification of all negative (13 of 13) and positive (35 of 35) proficiency test samples obtained from the National Veterinary Services Laboratories. In addition, all 6 negative and 50 of 51 positive diagnostic specimens tested were categorized correctly.  相似文献   

Weather-Centric Rangeland Revegetation Planning     

Stuart P. Hardegree  John T. Abatzoglou  Mark W. Brunson  Matthew J. Germino  Katherine C. Hegewisch  Corey A. Moffet  David S. Pilliod  Bruce A. Roundy  Alex R. Boehm  Gwendwr R. Meredith 《Strength and Conditioning Journal》2018,71(1):1-11

Invasive annual weeds negatively impact ecosystem services and pose a major conservation threat on semiarid rangelands throughout the western United States. Rehabilitation of these rangelands is challenging due to interannual climate and subseasonal weather variability that impacts seed germination, seedling survival and establishment, annual weed dynamics, wildfire frequency, and soil stability. Rehabilitation and restoration outcomes could be improved by adopting a weather-centric approach that uses the full spectrum of available site-specific weather information from historical observations, seasonal climate forecasts, and climate-change projections. Climate data can be used retrospectively to interpret success or failure of past seedings by describing seasonal and longer-term patterns of environmental variability subsequent to planting. A more detailed evaluation of weather impacts on site conditions may yield more flexible adaptive-management strategies for rangeland restoration and rehabilitation, as well as provide estimates of transition probabilities between desirable and undesirable vegetation states. Skillful seasonal climate forecasts could greatly improve the cost efficiency of management treatments by limiting revegetation activities to time periods where forecasts suggest higher probabilities of successful seedling establishment. Climate-change projections are key to the application of current environmental models for development of mitigation and adaptation strategies and for management practices that require a multidecadal planning horizon. Adoption of new weather technology will require collaboration between land managers and revegetation specialists and modifications to the way we currently plan and conduct rangeland rehabilitation and restoration in the Intermountain West.  相似文献   

Intake of Salt Cedar by Two Different Breeds of Sheep     

Zach B. Borroum  Cody B. Scott  Corey J. Owens 《Strength and Conditioning Journal》2018,71(1):115-118

Salt cedar (Tamarix spp.) readily invades and dominates riparian areas and lake basins throughout the western United States. Traditional control efforts (chemical and mechanical control) are expensive and provide limited long-term control. The salt cedar leaf beetle (Diorhabda elongata) provides a method of biological control through reduction in cover. However, population establishment of leaf beetles in some locations is often difficult because of environmental conditions. In previous research, goats readily consumed salt cedar, offering an alternative method of reducing salt cedar cover. For this study, we determined if sheep would consume salt cedar and consume a similar amount as goats. Twelve Rambouillet and 12 Suffolks lambs were fed salt cedar once daily (Trial 1) and three times daily (Trial 2). Intake of salt cedar by sheep was compared between breeds and with intake of salt cedar by goats (n = 10). Salt cedar was fed once a day in Trial 1 for 30 min over 15 d. Intake was recorded daily for individual animals. In Trial 2, salt cedar was offered three times daily for 13 d with intake recorded. There were no differences (P > 0.05) between breeds of sheep. In addition, sheep consumed more salt cedar than goats except on the last day of the study. When salt cedar was offered three times daily, both breeds of sheep increased intake and gained weight over the 13 d of feeding in Trial 2. By the end of the study, intake appeared to still be increasing. Collectively, these results illustrate that both Rambouillet and Suffolk sheep will consume a similar amount of salt cedar as goats and will provide another species of livestock that can be potentially used to reduce salt cedar cover.  相似文献   

Influence of harvest date on seed yield and quality in forage kochia     

Cody F. CREECH  Blair L. WALDRON  Corey V. RAMSOM  Dale R. ZOBELL  Joseph Earl CREECH 《农业科学与工程前沿(英文版)》2018,5(1):71

Forage kochia (Bassia prostrata) is used for rangeland reclamation and livestock and wildlife forage, but limited research has been conducted on its seed production. Therefore, this research evaluated the effect of harvest date on seed weight, germination, and seed yield of forage kochia subspecies virescens and grisea. Seed was harvested from individual plants for 3 years during October, November, and December. October harvest had the lightest 100-seed weights, with the November harvest slightly heavier than December, for most accessions. Cultivar Snowstorm and breeding line Sahsel, both subsp. grisea, had the greatest 100-seed weights in November, 155 and 143 mg, respectively, whereas, cv. Immigrant (subsp. virescens), the standard for forage kochia, ranked among the least for 100-seed weight. For most accessions, germination was lowest from the October harvest (11%–43%), with greater germination with November and December harvested seeds (43%–64%). Viable seed yields were greatest in November with the exception of two accessions, which peaked in October, indicating earlier maturity. Results indicate that forage kochia usually reaches optimum seed maturity by early November, after plants are exposed to freezing temperatures; however, earlier maturing accessions exist in both subspecies virescens and grisea.  相似文献   

Does adding microbial mechanisms of decomposition improve soil organic matter models? A comparison of four models using data from a pulsed rewetting experiment     

Corey R. Lawrence  Jason C. Neff  Joshua P. Schimel 《Soil biology & biochemistry》2009,41(9):1923-1934

Contemporary soil organic matter (SOM) models have been successful at simulating decomposition across a range of spatial and temporal scales using first-order kinetics to represent the decomposition process; however, recent work suggests the simplicity of the first-order representation of decomposition is not adequate to capture the microbially-driven dynamics of SOM decomposition over short timescales. For example, the response of soils to drying-rewetting events may best be explained by microbial and/or exoenzyme controls on decomposition. To test if adding these microbial mechanisms improves the ability of SOM models to simulate the response of soils to short-term environmental changes, we developed four different SOM decomposition models with varying mechanistic complexity and compared their ability to simulate soil respiration from a pulsed drying-rewetting laboratory-based experiment. Specifically, we tested the ability of the models to capture the timing and magnitude of soil CO₂ efflux in response to rewetting or constant moisture conditions. The results of the comparison suggest that the inclusion of exoenzyme and microbial controls on decomposition can improve the ability to simulate pulsed rewetting dynamics; however, less mechanistic first-order models prevail under steady-state moisture conditions. These modeling results may have implications for understanding the long-term response of soil carbon stocks in response to local and regional climate change.  相似文献   

Strange bedfellows? Techno-fixes to solve the big conservation issues in southern Asia     

Barry W. Brook  Corey J.A. Bradshaw 《Biological conservation》2012,151(1):7-10

The conservation challenges facing mega-biodiverse South and Southeast Asia in the 21st century are enormous. For millennia, much of the habitat of these regions was only lightly modified by human endeavour, yet now it is experiencing rampant deforestation, logging, biofuel cropping, invasive species expansion, and the synergies of climate change, drought, fire and sea-level rise. Although small-scale conservation management might assist some species and habitats, the broader sweep of problems requires big thinking and some radical solutions. Given the long expected lead times between progressive economic development and stabilization of human population size and consumption rates, we argue that ‘technological fixes’ cannot be ignored if we are to address social and fiscal drivers of environmental degradation and associated species extinctions in rapidly developing regions like southern Asia. The pursuit of cheap and abundant ‘clean’ energy from an economically rational mix of nuclear power, geothermal, solar, wind, and hydrogen-derivative ‘synfuels’, is fundamental to this goal. This will permit pathways of high-tech economic development that include intensified (high energy-input) agriculture over small land areas, full recycling of material goods, a transition from fossil-fuel use for transport and electricity generation, a rejection of tropical biofuels that require vast areas of arable land for production, and a viable alternative to the damming of major waterways like the Mekong, Murum and northern tributaries of the Ganges and Brahmaputra Rivers for hydroelectricity. Rational approaches that work at large scales must be used to deal with the ultimate, rather than just proximate, drivers of biodiversity loss in the rapidly developing regions of southern Asia.  相似文献   

Complex interplay between intrinsic and extrinsic drivers of long-term survival trends in southern elephant seals     

Siobhan C de Little  Corey JA Bradshaw  Clive R McMahon  Mark A Hindell 《BMC ecology》2007,7(1):3

Background  

Determining the relative contribution of intrinsic and extrinsic factors to fluctuations in population size, trends and demographic composition is analytically complex. It is often only possible to examine the combined effects of these factors through measurements made over long periods, spanning an array of population densities or levels of food availability. Using age-structured mark-recapture models and datasets spanning five decades (1950–1999), and two periods of differing relative population density, we estimated age-specific probabilities of survival and examined the combined effects of population density and environmental conditions on juvenile survival of southern elephant seals at Macquarie Island.  相似文献   

Fibrosarcoma adjacent to the site of microchip implantation in a cat     

Daly MK  Saba CF  Crochik SS  Howerth EW  Kosarek CE  Cornell KK  Roberts RE  Northrup NC 《Journal of Feline Medicine and Surgery》2008,10(2):202-205

A 14-year-old spayed female domestic shorthair cat presented with an interscapular mass. A computed tomography scan, biopsy, and histological examination revealed a fibrosarcoma adjacent to a pet identification microchip. Because the cat was previously vaccinated at this site, it is not possible to establish definitive causation of the fibrosarcoma, but this is the first report of a tumor in the vicinity of a microchip in a cat. Microchip-associated tumors have been reported in rodents and dogs. Veterinarians should be aware that because inflammation may predispose felines to tumor formation, separation and observation of vaccination and implantation sites are indicated. Adherence to American Association of Feline Practitioners (AAFP) vaccination guidelines and monitoring of microchip implantation sites are recommended.  相似文献   

Global veterinary opportunities and responsibilities: some recent graduates' perspectives     

Marshall ES  Smith R  Watts C 《Journal of veterinary medical education》2006,33(3):416-418

The veterinary profession has critical global responsibilities. To help meet these responsibilities, it is critical that the training programs for veterinary graduates provide them with the skills, knowledge, understanding, and professional attributes pertinent to meeting these responsibilities. The programs at US veterinary schools, in the full range from admissions, to curriculum, to post-graduate opportunities, fall short in many critical arenas.  相似文献   

Development of allometric leaf area models for intensively managed black walnut (Juglans nigra L.)     

Christopher E. Zellers  Michael R. Saunders  Robert C. Morrissey  Joshua M. Shields  Brian G. Bailey  Jacob Dyer  Jason Cook 《Annals of Forest Science》2012,69(8):907-913

? Introduction

Intensive plantation management of high-value hardwoods, such as black walnut (Juglans nigra L.), is focused on maximizing both stem form and growth at the stand and tree level. While significant research has focused on genetic improvement in black walnut, little is known about the production ecology of this species in plantation settings.

? Objectives

The aim of this study is to assess the applicability of nondestructive projected leaf area (PLA) estimation based on the pipe model theory in three single-aged J. nigra plantations representing discrete age classes ranging from 3 to 27?years of age.

? Results

Branch-level PLA was modeled as a function of branch basal cross-sectional area (R ²?=?0.875). Six nondestructive tree-level PLA models were assessed, with four models yielding R ²?>?0.90. Tree-level models performed well across age classes, with model fits comparable to previous studies in coniferous species.

? Conclusion

This study demonstrates that allometric approaches to modeling leaf area distribution in hardwoods are feasible, but future efforts may need to use different sampling approaches and/or quantify variables that have not been significant in conifers. This study represents an important first step into more quantitative analysis of production ecology of deciduous species in the CHFR of the USA.  相似文献