Comparison of 3 methods of selenium assessment in cattle.          下载免费PDF全文

C Waldner  J Campbell  G K Jim  P T Guichon    C Booker 《The Canadian veterinary journal. La revue veterinaire canadienne》1998,39(4):225-231

Three tests are routinely done to assess blood status of selenium in cattle: serum selenium, whole blood selenium, and glutathione peroxidase. The objective of this study was to compare the various analytical methods for determining blood selenium status in groups of mature cows and beef calves. Twenty to 30 blood samples per herd were collected from 8 beef herds in central Alberta and 1 dairy in Alberta herd twice a year from the spring of 1992 through the fall of 1995, and once from 185 spring calves in 2 beef herds in Saskatchewan. Serum and whole blood samples were submitted to 1 laboratory and whole blood samples were submitted to a 2nd laboratory. Samples for glutathione peroxidase determinations were submitted to a 3rd laboratory. Pearson's correlation coefficients and Cohen's kappa were calculated for each possible comparison among the different measures. The best agreement was observed between serum and whole blood analysis within Laboratory A. The remaining comparisons reflected poor agreement. Comparison of herd-level assessment resulted in better agreement than comparison of individual sample results among laboratories and procedures for all combinations tested. Serum selenium analysis was the only laboratory procedure for which external reference material was utilized. Serum selenium, whole blood selenium, and glutathione peroxidase measure different compartments of the blood selenium pool. The time frame of interest, supplementation practices, and the stability of recent dietary intake determine the optimum assessment method for individual animals or herds. Determination of the serum status or of blood selenium is more consistently measured at the herd-level than for individual samples.  相似文献   

Mutants of rabies viruses in skunks: immune response and pathogenicity.          下载免费PDF全文

N D Tolson  K M Charlton  R B Stewart  G A Casey  W A Webster  K MacKenzie  J B Campbell    K F Lawson 《Canadian journal of veterinary research》1990,54(1):178-183

In studies to develop an oral rabies vaccine for wildlife, the immune response to and pathogenicity of two types of mutants of rabies viruses were examined. Forty-five small plaque mutants were selected from cultures of ERA rabies virus treated with 8-azaguanine or 5-fluorouracil and tested for pathogenicity in mice. Two of these mutants AZA 1 and AZA 2 (low pathogenicity in mice) were given to skunks by oral (bait), intestinal (endoscope) and intramuscular routes. Additionally, challenge virus standard (CVS) rabies virus and mutants of this and ERA rabies virus (CVS 3766 and 3713, and ERA 3629) that were resistant to neutralization by specific antiglycoprotein monoclonal antibodies (and apathogenic in mice) were tested by various routes in skunks. Skunks given AZA 1 and AZA 2 were challenged at three months postinoculation with street rabies virus. After oral administration, there were very low rates of seroconversion with AZA 1 and AZA 2 and on challenge only 2/7 given AZA 1 and 1/8 given AZA 2 survived. None of the skunks given the other mutants orally seroconverted. AZA 2 produced a high rate of seroconversion (8/8) by the intestinal route and all challenged skunks in this group survived (7/7). All skunks vaccinated intramuscularly with AZA 1 (4/4) or AZA 2 (4/4) developed high levels of rabies neutralizing antibodies and survived challenge. The mutant CVS 3766, while apathogenic when given intracerebrally to adult mice, was consistently pathogenic by this route (and intranasally) in skunks. These results demonstrate that skunks are highly resistant to oral immunization by live rabies virus vaccines and that pathogenicity (by intracerebral route) of the mutant CVS 3766 is markedly different in mice and skunks.  相似文献   

Fatty acid supplementation and skin disease     

K L Campbell 《Veterinary Clinics of North America: Small Animal Practice》1990,20(6):1475-1486

The importance of dietary fatty acids to the health of the skin was recognized more than 60 years ago. Fatty acids are important in providing membrane fluidity and maintaining the cutaneous water permeability barrier. Fatty acids function as precursors of eicosanoids. Eicosanoids, which include prostaglandins and leukotrienes, influence cellular interactions, cellular proliferation, and inflammation. Certain diseases, such as atopy and hypothyroidism, are characterized by abnormalities in fatty acid metabolism. Dietary manipulations may be useful in the treatment of diseases mediated by eicosanoids.  相似文献   

Efficacy of paraherquamide against immature Trichostrongylus colubriformis in the gerbil (Meriones unguiculatus)   总被引：1，自引：0，他引：1  

D A Ostlind  W G Mickle  D V Ewanciw  F J Andriuli  W C Campbell  S Hernandez  S Mochales  E Munguira 《Research in veterinary science》1990,48(2):260-261

Paraherquamide was 98 to 100 per cent effective against six-day-old Trichostrongylus colubriformis infections in gerbils when given as single oral doses of 1.56 mg kg-1 and above. Doses of 0.78 or 0.39 mg kg-1 were 96 and 66 per cent effective, respectively. A single oral dose of 200 mg kg-1 was well tolerated.  相似文献   

Comparison of commercial broiler house lighting programs using LED and natural light: Part 1—spatial and temporal analysis of light intensity     

John E. Linhoss  Jeremiah D. Davis  Jesse C. Campbell  Joseph L. Purswell  Kelly G. Griggs  Carson M. Edge 《The Journal of Applied Poultry Research》2022,31(3):100272

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Light-energy processing and freezing-tolerance traits in red spruce and black spruce: species and seed-source variation     

Major JE  Barsi DC  Mosseler A  Campbell M  Rajora OP 《Tree physiology》2003,23(10):685-694

Red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) B.S.P.) are genetically and morphologically similar but ecologically distinct species. We determined intraspecific seed-source and interspecific variation of red spruce and black spruce, from across the near-northern margins of their ranges, for several light-energy processing and freezing-tolerance adaptive traits. Before exposure to low temperature, red spruce had variable fluorescence (Fv) similar to black spruce, but higher photochemical efficiency (Fv/Fm), lower quantum yield, lower chlorophyll fluorescence (%), and higher thermal dissipation efficiency (qN), although the seed-source effect and the seed-source x species interaction were significant only for Fv/Fm. After low-temperature exposure (-40 degrees C), red spruce had significantly lower Fv/Fm, quantum yield and qN than black spruce, but higher chlorophyll fluorescence and relative fluorescence. Species, seed-source effect, and seed-source x species interaction were consistent with predictions based on genetic (e.g., geographic) origins. Multi-temperature exposures (5, -20 and -40 degrees C) often produced significant species and temperature effects, and species x temperature interactions as a result of species-specific responses to temperature exposures. The inherent physiological species-specific adaptations of red spruce and black spruce were largely consistent with a shade-tolerant, late-successional species and an early successional species, respectively. Species differences in physiological adaptations conform to a biological trade-off, probably as a result of natural selection pressure in response to light availability and prevailing temperature gradients.  相似文献   

Traditional agroforestry practices in Zimbabwe     

B. M. Campbell  J. M. Clarke  D. J. Gumbo 《Agroforestry Systems》1991,14(2):99-111

Traditional agroforestry systems in the communal areas of Zimbabwe are described. There are systems centered on main fields, on home gardens, on homesites and on grazing areas. In the main fields, the major tree-related management practice is the conservation of preferred indigenous fruit trees. Fruit trees are also the focus of forestry activities around the gardens and the homesite; but here it is the planting of exotic species. In a localized area of Zimbabwe Acacia albida is important in fields. There is almost no use of tree fallows in Zimbabwe. Trees in grazing areas have numerous roles, but at present there is little knowledge about traditional management practices in these areas. In the development of agroforestry systems in Zimbabwe it is suggested that those systems designed to improve fodder production will make a significant contribution to farm productivity because of the importance of cattle in the farming system and the present fodder shortage. Interventions involving the planting of fruit trees are likely to be very successful, as there is much interest in such planting. Another area that needs to be developed is that of tree plantings to improve soil fertility.  相似文献   

Alkaloids from Cyrtanthus elatus     

Herrera MR  Machocho AK  Nair JJ  Campbell WE  Brun R  Viladomat F  Codina C  Bastida J 《Fitoterapia》2001,72(4):444-448

The alcoholic extract of the fresh bulbs of Cyrtanthus elatus yielded zephyranthine (1) and 1,2-O-diacetylzephyranthine (2), together with three other known alkaloids. Complete assignment of 1H and 13C NMR spectra of compounds 1 and 2 was done by employment of two-dimensional NMR techniques.  相似文献   

Effects of forest floor planting and stock type on growth and root emergence of Pinus contorta seedlings in a cold northern cutblock   总被引：1，自引：0，他引：1  

D. Bruce Campbell  Steven Kiiskila  Leanne J. Philip  Janusz J. Zwiazek  Melanie D. Jones 《New Forests》2006,32(2):145-162

A two-year field trial was conducted to determine the growth response, and root emergence pattern of interior lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) seedlings in response to container type and forest floor removal. Seedlings were grown in Styroblocks^TM, Copperblocks^TM, or AirBlocks^TM, and were planted directly into the undisturbed forest floor or into manually prepared planting spots where the forest floor had been scraped away to expose the mineral soil. Seedlings planted into scalped planting spots exhibited marginally but significantly (7%) greater above-ground growth rates (seedling stem volume); whereas seedlings planted into the forest floor produced significantly more (11%) new roots. There were no differences in above- or below-ground biomass. Seedlings grown in Copperblock^TM containers produced a higher proportion of roots near the top of the plug when tested at lifting, however this pattern was not observed in the field. Given that scalping is more costly than forest floor planting, and that the increased shoot growth was relatively small, we recommend that forest floor planting be considered as an alternative to manual spot scalping for sites, such as the site tested here: those with cold, but well-drained soils and where competition from other plants is not a serious problem.  相似文献   

Effect of an anti‐gonadotropin‐releasing factor vaccine on sexual and aggressive behaviour in male pigs during the finishing period under Australian field conditions          下载免费PDF全文

B Karaconji  B Lloyd  N Campbell  D Meaney  T Ahern 《Australian veterinary journal》2015,93(4):121-123

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