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Common root rot (Aphanomyces euteiches Drechs.) has become a very destructive disease in the French pea crops since 1993. For an accurate investigation of the virulence variability among French A. euteiches populations and between French and foreign populations, a new set of differential pea genotypes was developed. Thirty-three American and European pea lines, displaying different levels of resistance, were screened in a growth chamber against two French isolates. Symptoms (disease severity from 0 to 5, evaluating symptom surface on roots and epicotyl) and percentage of top fresh weight (inoculated/uninoculated top fresh weight ratio) were measured. From this screening 12 relatively resistant lines, from various genetic backgrounds, were identified along with a highly susceptible control. This set of 13 genotypes was inoculated under controlled conditions with 14 isolates from France, Sweden, USA, Canada and New Zealand, to investigate genotype–isolate interactions. Root symptoms were rated (disease severity), and a susceptibility/resistance threshold was established at disease severity = 1. Significant quantitative interactions were observed, and five 'resistance patterns' were identified, leading to a set of six pea genotypes: Baccara (susceptible), Capella, MN313, 902131, 552 and PI180693. Fields trials of this set in 1999 and 2000 gave the same resistance rankings than in growth chamber conditions. This set will allow more accurate assessments of the variability in virulence/aggressiveness of A. euteiches isolates from France and foreign countries, and further investigations of the epidemiological and genetic basis of pea–A. euteiches interactions.  相似文献   
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The aim of this study was to identify possible effects of different vaccination strategies (concomitantly or not) against brucellosis and clostridia on intake, performance, feeding behavior, blood parameters, and immune responses of dairy heifers calves. Fifty heifers calves were enrolled [38 Gyr (Zebu, Bos taurus indicus) and 12 5/8 Holstein Gyr]. At 120 d of age, animals were randomly distributed among 3 groups: B (n = 18), vaccinated against brucellosis; C (n = 14), vaccinated against clostridia and CB (n = 18), vaccinated concomitantly for both. Rectal and thermographic temperatures were evaluated on days 1, 0, 1, 2, 3, 5, 7,10, 14, and 28 relatives to the vaccination day. Feed and water intake, body weight (BW), and feeding behavior were monitored daily by an electronic feeding system. Blood was sampled on days 0, 3, 7, 14, and 28, relative to the vaccination day for determination of glucose and -hydroxybutyrate (BHBA) concentrations. Blood sampled on day 0 (prevaccination) and on days 28 and 42 were used to evaluate the immune response against Brucella abortus and clostridia. There was an increase in rectal temperature between the first and the third day postvaccination in the 3 groups. The thermography revealed an increase of local temperature for 7 d on groups B and CB. Group C had increased local temperature for a longer period, lasting for up to 14 d. Dry mater intake was reduced for groups B and CB, but no alteration was observed for group C. No alterations regarding initial BW, final BW, average daily weight gain, and feed efficiency were observed. No differences were observed for the 3 vaccination groups for blood parameters throughout the evaluation period. The concomitant vaccination against brucellosis and clostridia led to lower neutralizing antibody titers against epsilon toxin of Clostridium perfringens and botulinum toxin type C of C. botulinum (C > CB > B). When cellular proliferation assay and serological tests to B. abortus were evaluated, no differences were observed between groups B and CB. The present results indicate that the concomitant vaccination against brucellosis and clostridia has no relevant impact on the intake, performance, and feeding behavior of dairy calves. However, the concomitant vaccination of vaccines against these 2 pathogens impacts animal immunity against clostridial infections.  相似文献   
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In human medicine, spinal pain and radiculopathy are commonly managed by computed tomography (CT)‐guided facet joint injections and by transforaminal or translaminar epidural injections. In dogs, CT‐guided lumbosacral epidural or lumbar facet joint injections have not been described. The aim of this experimental, ex vivo, feasibility study was to develop techniques and to assess their difficulty and accuracy. Two canine cadavers were used to establish the techniques and eight cadavers to assess difficulty and accuracy. Contrast medium was injected and a CT scan was performed after each injection. Accuracy was assessed according to epidural or joint space contrast opacification. Difficulty was classified as easy, moderately difficult, or difficult, based on the number of CT scans needed to guide insertion of the needle. A total of six translaminar and five transforaminal epidural and 53 joint injections were performed. Translaminar injections had a high success rate (100%), were highly accurate (75%), and easy to perform (100%). Transforaminal injections had an moderately high success rate (75%), were accurate (75%), and moderately difficult to perform (100%). Success rate of facet joint injections was 62% and was higher for larger facet joints, such as L7‐S1. Accuracy of facet joint injections ranged from accurate (37–62%) to highly accurate (25%) depending on the volume injected. In 77% of cases, injections were moderately difficult to perform. Possible complications of epidural and facet joint injections were subarachnoid and vertebral venous plexus puncture and periarticular spread, respectively. Further studies are suggested to evaluate in vivo feasibility and safety of these techniques.  相似文献   
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OBJECTIVE: To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE). ANIMALS: 22 healthy 5- to 15-year-old horses. PROCEDURES: Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection. RESULTS: Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.  相似文献   
8.
The sustainability of self-governingirrigation schemes is currently underpressure in many countries as publicfinancial support is decreasing.Furthermore, growing global concernregarding water scarcity means thatefficient water use is essential.Theoretically the choice and implementationof a water-pricing system should play acentral role in achieving this objective,both by recovering water costs and byencouraging farmers to adopt more efficientbehaviour. In the Senegal River Delta newlyestablished water users associations (WUAs)have chosen low water charges, which areaffordable for the majority of farmers butwhich underestimate long-term maintenancecosts. Combined with the difficulty ofcollecting and managing farmers' fees, thischoice has drawn them into a vicious circleleading to scheme deterioration and poorwater service. New alternatives have beendiscussed with them using a simulation toolthat takes into account both the watercosts and the farmers' incomes. Comparedwith the present fixed water charge basedonly on cultivated land, a two-part optionbased both on equipped and irrigated areasensures the recovery of fixed expenses suchas maintenance, while encouraging farmersto intensify their farming systems byadopting double cropping. Neverthelesschoosing a relevant water charge does notensure by itself the sustainability of anirrigation scheme. Combined supportproviding WUAS and farmers with efficientadvice regarding management andorganisational skills should alsocontribute significantly to achieve thisprime objective.  相似文献   
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As a response to inadequacy in canal water supplies, farmers in Pakistan have invested in private tubewells to control irrigation water resources. Also, they participate in surface water and groundwater markets that take place within tertiary units of the irrigation system.The present paper describes the functioning and organization of these water markets, using information collected in sample watercourses of the Fordwah Branch irrigation system, South-Punjab, Pakistan. The variability in type and intensity of water markets is investigated with regard to access to water resources and farm production strategies and constraints.  相似文献   
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The pattern of increasing species body size with increasing latitude has been noticed in different groups of animals. Here, we used seven key environmental factors and independent contrasts to assess body size latitudinal clines in Cyprinidae at two phylogenetic levels (inter‐ and intragenera), which were defined using a genus‐level supertree. Model selection procedures revealed that environmental factors shaping body size variation in Cyprinidae differed according to the phylogenetic scale considered. At the higher phylogenetic level, we found that both temperature (negative effect) and habitat availability (positive effect of drainage basin surface area) constituted mechanistic explanations of large‐scale body size distribution. No temperature‐related body size cline was observed at the intragenus level. Instead, competitive interaction (negative effect of species richness), habitat availability (positive effect of drainage basin surface area), migration ability and available energy (positive effects of glacial coverage and actual evapotranspiration) constitute alternative explanations at this lower phylogenetic scale. We conclude that (i) at the intergenus level, cyprinids do show a tendency to be smaller at high temperatures and larger at low temperatures, (ii) this tendency no longer exists at the intragenus level, (iii) latitude per se is a weak predictor of body size clines whatever the taxonomic level analysed, (iv) generalising geographical body size patterns may be rendered difficult by the superimposition of a series of mechanisms across different taxonomic scales, and (v) habitat size, here acting positively at both taxonomic scales, may play a major role in shaping riverine species body size clines.  相似文献   
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