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排序方式: 共有169条查询结果,搜索用时 15 毫秒
41.
Alexander J. Smart Roger N. Gates Patricia S. Johnson Rebecca Schafer 《Strength and Conditioning Journal》2012,65(5):506-515
Combined growing- and dormant-season pasture use has potential to increase herbage harvest without causing the undesirable shift in species composition that occurs with excessive utilization. The objective of this study was to determine the effect of summer clipping on winter pastures and winter clipping on summer pastures regarding standing crop, plant community composition, and forage quality. The study was conducted from 2003–2006 at the Antelope and Cottonwood Research Stations located in the mixed-grass prairie of western South Dakota. At each location, the experimental design was a randomized complete block with three replications that included 18 clipping treatments arranged as a split-split plot. Whole plots consisted of four summer clipping dates (May–August). Subplot treatments were two clipping intensities (clipped to residual height to achieve 25% or 50% utilization). Sub-subplots consisted of two winter clipping intensities (unharvested or clipped to a residual height to achieve a total utilization of 65%). Two winter control treatments were arranged in the subplot and split into two clipping intensities of 50% and 65% utilization. Winter biomass for the May 25% clipping treatment was similar to winter biomass for winter-only clipping. No increase in forage quality resulted from summer clipping compared with winter clipping. Three consecutive yr of combined growing-season and dormant-season defoliation to 65% utilization resulted in no change in functional group composition compared with ≤ 50% utilization treatments. Clipping in June resulted in reduced midgrass biomass at both stations and increased shortgrass biomass at Cottonwood. Results suggest that producers could combine growing and dormant-season grazing to increase the harvest of herbage on mixed-grass prairie, but should change season of use periodically to avoid an undesirable shift in plant composition. 相似文献
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43.
L. Smart K. Hopper J. Aldrich J. George P. Kass S. Haskins 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2009,23(2):388-391
Background: Urine specific gravity (USG) is used clinically to estimate urine osmolality (UOsm). Although USG has been shown to have a linear correlation with UOsm in dogs, the relationship is altered when there are significant numbers of high molecular weight (MW) molecules in the urine.
Hypothesis: USG would no longer predict UOsm in dogs given intravenous hetastarch (670/0.75)(HES).
Animals: Eight healthy employee-owned adult dogs.
Methods: Prospective, controlled experimental study. USG and UOsm were measured every 30 minutes from t=0 minutes to t=360 minutes. Dogs were administered 20mL/kg of either NaCl 0.9% (control group, n=4) or HES (treatment group, n=8) IV over 1 hour starting at t=90 minutes.
Results: There was a decrease in UOsm in both groups starting at t=120 minutes and continuing for the study duration, and there was no significant difference in UOsm between treatment and control groups across all time points. There was an appropriate decrease in USG from t=120 minutes for the control group. In the treatment group, USG increased significantly at t=120 minutes ( P = .0006), t=150 minutes ( P = .0002), and t=180 minutes ( P = .0044). The largest increase in USG occurred at t=150 minutes with a mean USG of 1.070 ± 0.021 (range 1.038-1.104).
Conclusions and clinical importance: Urine specific gravity should not be used to estimate urine solute concentration in dogs following the administration of 20mL/kg of HES. In a clinical setting, the evaluation of USG following this dose of HES may lead to an overestimation of urine concentration. 相似文献
Hypothesis: USG would no longer predict UOsm in dogs given intravenous hetastarch (670/0.75)(HES).
Animals: Eight healthy employee-owned adult dogs.
Methods: Prospective, controlled experimental study. USG and UOsm were measured every 30 minutes from t=0 minutes to t=360 minutes. Dogs were administered 20mL/kg of either NaCl 0.9% (control group, n=4) or HES (treatment group, n=8) IV over 1 hour starting at t=90 minutes.
Results: There was a decrease in UOsm in both groups starting at t=120 minutes and continuing for the study duration, and there was no significant difference in UOsm between treatment and control groups across all time points. There was an appropriate decrease in USG from t=120 minutes for the control group. In the treatment group, USG increased significantly at t=120 minutes ( P = .0006), t=150 minutes ( P = .0002), and t=180 minutes ( P = .0044). The largest increase in USG occurred at t=150 minutes with a mean USG of 1.070 ± 0.021 (range 1.038-1.104).
Conclusions and clinical importance: Urine specific gravity should not be used to estimate urine solute concentration in dogs following the administration of 20mL/kg of HES. In a clinical setting, the evaluation of USG following this dose of HES may lead to an overestimation of urine concentration. 相似文献
44.
Glenn W. Dawson Kevin J. Doughty Alastair J. Hick John A. Pickett Barry J. Pye Lesley E. Smart Lester J. Wadhams 《Pest management science》1993,39(4):271-278
A range of 3, 5-disubstituted 1,3, 5-thiadiazinane-2-thiones are described which decompose in moist air to give organic isothiocyanates. Organic isothiocyanates are the main biologically active catabolites from the glucosinolate components of crucifers. The thiadiazinanethiones provide a source of organic isothiocyanates for biological studies and examples of tests with pathogens and insect pests of oilseed rape are given. 相似文献
45.
Roger M. Smith Kirpal C. Madahar W. G. Salt Nigel A. Smart 《Pest management science》1988,23(4):337-349
The rates of uptake and loss of ethylenethiourea (ETU) in lettuces were studied following the application of ethylenethiourea or selected ethylenebisdithiocarbamate fungicides to the soil or to the leaves of potgrown plants. Analyses were carried out using high performance liquid chromatographic analysis of ETU. The amounts of ETU residues on leaves decreased rapidly and were negligible within a week, unless ethylenebisdithiocarbamate fungicides had been applied to the soil, as the latter were degraded simultaneously to give additional ETU which was then taken up by the plants. 相似文献
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An outbreak of type C botulism involving three-week-old broiler chickens on deep litter is described. No direct source of toxin was found. Cl botulinum type C was distributed widely in the litter, and several thousand per gram were demonstrated both in the litter and in the intestinal contents of chicken. 相似文献
49.
J Storz R A Smart M E Marriott R V Davis 《American journal of veterinary research》1966,27(118):633-641
50.
The sternal bursa developed as a microscopically recognizable synovial sac in turkeys at about 4 1/2 to 6 weeks of age. In birds 12 weeks old it was difficult to delineate the bursa grossly although microscopically it was a definite structure. After 12 weeks, the walls of the bursa were thick enough that the limits of the sac could be determined grossly. The synovial membrane was in the subcutis, and microscopically was a vascular band of loose to dense connective tissue of variable thickness. Laterally the membrane was folded so that in cross section it appeared as a tonguelike projection of variable length into the cavity. The lining cells centrally were flat fibroblasts while laterally they were cuboidal, particularly over the lateral folds. In older turkeys the cuboidal lining cells were sometimes stratified. 相似文献