Hyperlipemia and Ketonuria in an Alpaca and a Llama     

David E. Anderson  Peter D. Constable  Kathleen E. Yvorchuk  Neil V. Anderson  Guy St-Jean  Linda Rock 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(3):207-211

An alpaca and a llama in late stages of gestation were evaluated for lethargy, anorexia, and recumbency. Both camelids had cloudy, white, turbid serum, elevated serum triglyceride (1564, 5658 mg/dL, respectively) and cholesterol (158, 297 mg/dL, respectively) concentrations, and ketonuria. Signs of fetal stress were evident ultrasonographically in the alpaca, and a live cria was delivered by Cesarean section performed under general anesthesia. The alpaca developed severe metabolic acidosis, hepatic lipidosis, and acute renal failure secondary to renal lipidosis and died 36 hours after admission despite medical therapy. Histopathology revealed renal and hepatic lipidosis and neutrophilic pancreatitis. The cria died 72 hours after birth. The llama responded to IV electrolyte, dextrose, and regular crystalline insulin therapy. The pregnancy was maintained, and the llama was discharged from the hospital 20 days after admission. Two months after discharge, the llama gave birth to a live, 5 kg cria. Findings of hypertriglyceridemia, hypercholesterolemia, elevated sorbitol dehydrogenase activity, metabolic acidosis, azotemia, and ketonuria occurred in these two camelids. Based on this report, camelids appear to be similar to both horses and cattle in their response to severe energy imbalances in late gestation.  相似文献   

Quantitative Changes Associated with Calving in the Levels of Bovine Immunoglobulins in Selected Body Fluids I. Changes in the Levels of IgA, IgG1 and Total Protein          下载免费PDF全文

J. E. Butler  C. S. Pierce  C. A. Rock    C. A. Kiddy 《Canadian journal of veterinary research》1972,36(3):234-242

Levels of bovine IgA, IgG1 and total protein (TP) were determined in serum, saliva, tears and individual quarter lacteal secretions of six Holstein-Friesian cows sampled from six weeks before to four weeks after parturition. Hierarchal analyses of variance indicated significant variations among weeks, cows and quarters of the udder. A precipitous but non proportional drop in the levels of IgA and IgA1 in lacteal secretions occurred at calving. There was a concomitant increase in IgG1, and decrease in IgA, in serum. Correlation studies supported the concept of selective transport of IgG1 from serum to lacteal secretions in regulated amounts independent of serum IgG1 levels. Changes in the IgG1/TP ratio of serum and lacteal secretions supported the idea of a decrease in the selective transport mechanism. Correlation studies and estimations of secretory IgA (SIgA) in serum suggest that serum IgA is derived from IgA synthesized in secretory tissues. Highly significant correlations between IgA and IgG1 levels in all secretions postpartum suggest that local IgA synthesis and either IgG1 transport or local IgG1 synthesis are initiated by the same stimuli. Although some of the variation in the level reported for IgA and IgG1 in secretions resulted from protein dilution, much of the variation represents physiological differences between individual animals and tissues in the same animal. An IgG2/IgG1 ratio approaching that of serum occurred in a mastitic quarter of one cow. IgA was the principal immunoglobulin in saliva and tears, comprised a greater proportion of the immunoglobulin in milk whey than in prepartum lacteal secretions and was a minor immunoglobulin in bovine serum.  相似文献   

Metaflumizone-A new ectoparasiticide for dogs and cats.     

Michael K Rust  Douglas Rugg  Dave Rock 《Veterinary parasitology》2007,150(3):175-176

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Population dynamics of tree species in southern Quebec,Canada: 1970–2005     

Louis Duchesne  Rock Ouimet 《Forest Ecology and Management》2008

Over the last few decades, several phenomena contributed to modify the structure and composition of the eastern North American forests. Along with forest management, disturbances such as insect defoliation, global environmental changes, acid deposition, and rising atmospheric CO₂ concentrations, have been identified as phenomena that could affect forest structure and composition. Currently, there is very little quantitative information on the resulting effect of multiple disturbances on the main parameters of forest dynamics (growth, mortality, and recruitment). Using available data from the Quebec permanent sample plots network, we analyzed the ecological response of tree species populations to the combined effect of contemporary global environmental changes, disturbance regimes, and forest management practices over the last 30 years in southern Quebec. The results indicate that the main parameters of forest dynamics changed considerably over the last three decades. The last spruce budworm outbreak initiated a successional change in coniferous stands. The basal area of Abies balsamea and Picea glauca, the most abundant coniferous species, decreased by 29.7%, while pioneer species abundance increased. For late successional deciduous species, observed changes in forest dynamics appear to be mainly associated with global environmental changes rather than with natural disturbances or forest harvesting. The results indicate that inferring responses of tree population dynamics to global environmental changes can be very complex or even misleading considering the confounding effects of other disturbance agents. The results also suggest that the ecosystem-based management approach promoted by forest ecologists, aimed at maintaining landscape stand composition and structures similar to those characterizing natural environments, will not be easily achieved. Forest ecosystems are highly dynamic and disturbances other than tree harvesting appear to have been the major factors affecting their pattern of change over the last three decades. Forest managers should consider adaptive management approaches that will consider the contemporary evolution of forest ecosystems in a changing environment.  相似文献   

Pretreating landfill leachate with peat to remove metals     

J. K. McLellan  C. A. Rock 《Water, air, and soil pollution》1988,37(1-2):203-215

In this investigation, the capacity of peat to treat two different landfill leachates was determined. Freundlich isotherms showed that, for the tested metals (Cd, Cr, Cu, and Pb), an increased time of contact increased the level of adsorption over the entire range of influent values studied. In addition, metal interaction may play an important role in the adsorption of metals from leachate, as the various metal ions compete for the available adsorption sites on the peat. Column studies using two leachates, one from a municipal refuse fill (Al, Ca, Cd, Fe, Mg, Na, and Pb), and one from a fill which receives mainly oil and fly ash (Al, Ca, Cr, Fe, Mg, Mn, Na, Pb, and V), were conducted to establish design parameters for full-scale design. The efficiency of treatment was evaluated as a function of factors important for developing filter design criteria. Further considerations were given to filter longevity and ease of replacement, as well as for the ultimate disposal of the peat from the filters. For the municipal leachate a compaction density of 0.12 g mL^?1 gave the best results as clogging occurred at higher densities, whereas 0.18 g mL^?1 provided the best removal for the industrial leachate. While peat is incapable of adequately removing metals to acceptable levels for direct discharge, peat can provide substantial removal as a pretreatment process at low hydraulic loadings. Desorption of up to 50% was found when deionized water was applied to spent columns so ultimate disposal of the peat would require a dry environment.  相似文献   

Influence of dietary fat and vitamin E supplementation on free radical production and on lipid and protein oxidation in turkey muscle extracts     

Gatellier P  Mercier Y  Rock E  Renerre M 《Journal of agricultural and food chemistry》2000,48(5):1427-1433

The objectives of this study were to investigate the effects of dietary fat (6% soy oil or rapeseed oil or tallow) and alpha-tocopheryl acetate supplementation at two levels (30 or 200 ppm) on radical production, measured by ESR spectroscopy, and on lipid and protein oxidation in turkey muscle extracts oxidized by an enzymic system (NADPH, ADP, FeSO(4)/cytochrome P450 reductase). Two muscles were tested: pectoralis major (glycolytic) and sartorius (oxidative) muscles. Radical production measured by ESR was higher in pectoralis major muscle than in sartorius muscle, whereas lipid and protein oxidation was more important in sartorius muscle, showing the importance of the pro-/antioxidant ratio in oxidative processes in muscular cells and of the measurement methodology to appreciate the free radical production. Dietary fat had no effect on the level of ESR signals, whereas feeding of animals with soy oil induced higher oxidation of lipids. Protein oxidation was less sensitive to the nature of the dietary fat than lipid oxidation. Vitamin E supplementation significantly decreased radical production, as measured by ESR spectroscopy. Vitamin E also decreased lipid and protein oxidation, but the effect of vitamin E on protein oxidation was less pronounced than on lipid oxidation.  相似文献   

Tracing sources of soil nitrate using the dual isotopic composition of nitrate in 2 M KCl-extracts     

L. Rock  B.H. Ellert  B. Mayer 《Soil biology & biochemistry》2011,43(12):2397-2405

Soils comprise a critical interface between the atmosphere, lithosphere, hydrosphere and biosphere, and play a major role in the cycling of nitrogen (N), an element crucial to plant growth. Isotope techniques constitute a powerful tool to study the origin and fate of N compounds (e.g. NO₃⁻) within the environment including soils. The objective of our study was to test the usefulness of the isotope composition of soil NO₃⁻ extracted with 2 M KCl (soil NO₃) as a tool to investigate the origin and fate of NO₃⁻ in the environment. Specifically issues related to repeat extractions, crop type, length of fertilization, and soil depth were addressed. Soils from four contrasting agricultural management regimes were sampled. Within the relatively confined study area (4 ha), the isotopic compositions of soil NO₃ differed markedly due to management treatments (up to 6 and 17‰ for δ¹⁵N and δ¹⁸O, respectively), but were repeatable among replicate plots (±1‰). Differences in both δ¹⁵N and δ¹⁸O values were observed between legume and non-legume treatments, as well as fertilized versus non-fertilized treatments, which were larger than the variability observed between replicate plots. Differences in the isotopic composition of extractable soil nitrate were not limited to the surface layer, but also occurred within deeper soil layers. This study indicates that the analysis of the natural abundance stable isotope composition of soil NO₃ may provide a promising additional tool for tracing the origin and fate of NO₃⁻ in the soil zone.  相似文献   

Aspen bark photosynthesis and its significance to remote sensing and carbon budget estimates in the boreal ecosystem     

V. I. Kharouk  E. M. Middleton  S. L. Spencer  B. N. Rock  D. L. Williams 《Water, air, and soil pollution》1995,82(1-2):483-497

Aspen bark was investigated for photosynthetic function, pigment content, and spectral characteristics during the 1993–1994 Boreal Ecosystem-Atmosphere Study (BOREAS) summer field campaigns in the boreal zone of Saskatchewan, Canada. Parameters related to photosynthetic function were similar for bark and leaves: chlorophyll (Chl) concentration; fluorescence responses; and spectral reflectance. Similar increases along a vertical gradient from base to tree top were observed for incident photosynthetically active radiation (PAR), photosynthetic pigment content, photosynthetic capacity, and spectral reflectance variables. Since transmittance of aspen bark periderm was 20–30% in the blue, and 50–60% in the red Chl absorption bands, the PAR available to the photosynthetic cortical layer in the natural, canopy environment (<1000 μmol m^?2 s^?1) was sufficient to support positive net assimilation (<8–10 νmol CO₂ m^?2 s^?1) under ideal conditions (e.g., light, temperature, saturating CO₂), a rate approximately 30–50% that of leaves. However, the respiring tissues comprising the greater fraction of bark tissue bias the balance of CO₂ exchange in favour of respiration for the whole bark. Therefore, net photosynthesis under ambient conditions on the whole bark was, in general, negative. The total bark surface area was estimated to contain 17–40% of the whole tree Chl. The contribution of the bark surface area fraction of the full canopy (leaves plus bark) increased with age (<60 years), with a similar trend expected for bark in total tree (and stand) photosynthesis. A spectral reflectance variable, the red edge inflection point (REIP), was related to total bark Chl content (r²=0.74). A better predictive relationship (r²=0.82) for total bark Chl was observed using a spectral index calculated from the reflectance ratio of two narrow wavebands (R3/R2: R2 and R3 are between 0.715–0.726 μm and 0.734–0.747 μm, respectively), which may have greater utility in landscape remote sensing. The bark spectra for Chlcontaining bark should improve understanding of carbon balance in aspen forests, based on landscape-level radiative transfer simulations.  相似文献   

Evaluation of slowly degraded proteins: dehydrated alfalfa and corn gluten meal     

D W Rock  T J Klopfenstein  J K Ward  R A Britton  M L McDonnell 《Journal of animal science》1983,56(2):476-482

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玉米F_2群体中偏分离RFLP标记在染色体上的分布及原因分析     

曹永国  王国英  王守才  魏艳玲  卢江  谢友菊  戴景瑞 《中国农业大学学报》1998,(Z3)

研究了利用玉米85个 DNA 限制性片段长度多态性(RFLP)标记在玉米自交系7922与5003杂交 F2群体中的分离。结果表明,8.33%的标记显著或极显著地偏离了预期的孟德尔比例而表现偏分离,发现了2个偏分离的染色体热点,即第1染色体上的 umc128-umc107和第3染色体上的 asg24-asg48,其偏分离形成的主要原因是存在配子体选择。  相似文献