Salmonella contamination of poultry flocks in The Netherlands     

A W vd Giessen  R Peters  P A Berkers  W H Jansen  S H Notermans 《The Veterinary quarterly》1991,13(1):41-46

The contamination of poultry in the Netherlands with Salmonella enteritidis was tested. For this, different methods (detection of S. enteritidis in faecal samples of 25 g; detection of S. enteritidis in cloacal swabs; detection of S. enteritidis by serological testing of antibodies in serum) were compared for their efficiency to detect S. enteritidis in flocks of poultry. Testing of faecal samples clearly yielded the best results. This method was used in a transmission study, in which 14 flocks descending from a contaminated primary mother flock were screened for the presence of S. enteritidis. The method was also used for screening 49 flocks of laying hens and 52 flocks of broiler chickens throughout the Netherlands. From the transmission study it became clear that S. enteritidis, phage type 2 (Dutch phage set) was isolated both from the mother flock and from five of the descendent flocks. Screening of poultry flocks for the presence of salmonella revealed that salmonella was present in 47% of the layer flocks and in 94% of the broiler flocks. S. enteritidis was isolated from 15% of the flocks screened.  相似文献   

Letter to Editor          下载免费PDF全文

Chand Khanna DVM  PhD  DACVIM  David Vail DVM  DACVIM  Mona Rosenberg DVM  DACVIM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2016,30(1):9-9

  相似文献   

Determinants of income-earning strategies and adoption of conservation practices in hillside communities in rural Honduras     

Hans G.P. Jansen  Angel Rodriguez  Amy Damon  John Pender  Jacqueline Chenier  Rob Schipper 《Agricultural Systems》2006

Based on the results of participatory diagnostic surveys conducted in 95 rural communities in the hillsides of Honduras, we determine income earning strategies at the community level; identify their main determinants; and analyze the adoption of of conservation practices. Eight income-earning strategies were distinguished that reflect differences in comparative advantage between communities. We explain the choice of income earning strategy using a multinomial logit model that includes biophysical, economic, social and institutional variables. We use a probit model to show that adoption of conservation practices is determined by the type of income earning strategy, population density, market access, and organizational variables.  相似文献   

Soil phosphorus status and turnover in central-European beech forest ecosystems with differing tree species diversity   总被引：1，自引：0，他引：1  

U. Talkner    M. Jansen  & F. O. Beese 《European Journal of Soil Science》2009,60(3):338-346

Problems in phosphorus (P) nutrition of forest trees raise questions concerning the soil P concentrations, pools and turnover in forests. In addition, it is not clear if, and to what extent, tree species diversity has an influence on the soil P status and turnover. The aim of this study was to investigate the P status and turnover in beech ( Fagus sylvatica L.) -dominated forest ecosystems on loess over limestone and to elucidate what role heterogeneities in tree species diversity would play. The soils of mixed species stands contained more organically bound P (710–772 kg ha⁻¹) than those of pure beech stands (378 kg ha⁻¹), whereas the inorganic P content differed little between the stand types. A large proportion (44–55%) of the total soil P was organically bound. This fraction was mainly dependent on the clay content of the soils and not on the tree diversity. The P input with leaf litter (1.4–2.1 kg ha⁻¹ year⁻¹) showed a tendency to increase with increasing diversity. The apparent P turnover times in the organic surface layers differed, with shorter turnover times in mixed species stands (2–3 years) than in pure beech stands (10 years). Possible explanations for the different turnover times were differences in the litter quality, interactions in mixed species litters and the soil pH and base saturation. Hence, the tree species mainly influence the apparent P turnover time in the organic surface layer, whereas the P concentrations and pools in the mineral soil are determined by the soil properties, particularly the clay content.  相似文献   

Changes in landscape naturalness derived from a historical land register—a case study from NE Germany     

Florian Jansen  Stefan Zerbe  Michael Succow 《Landscape Ecology》2009,24(2):185-198

  相似文献   

Predicting adoption of double cropping in paddy fields of northern Iran: a comparison of statistical methods     

Solmaz Nadaf Fahmideh  Mohammad Sadegh Allahyari  Christos A. Damalas  Zahara Daghighi Masouleh  Mona Ghazi 《Paddy and Water Environment》2017,15(4):907-917

Factors affecting the adoption of double cropping were explored in rice farms of Fouman County of Guilan Province in northern Iran using artificial neural networks (ANNs), linear discriminant analysis (LDA), and logistic regression (LGR). Eleven factors (age, education, occupation, family size, type of farm ownership, distance to the agricultural service center, attending agricultural extension courses, use of financial resources and bank loans, number of domestic animals, area under cultivation, and social participation) were examined. An additional objective was to compare the ability of the three models in predicting the adoption of double cropping. ANNs showed an overall predictive power of 89.8%. LDA showed an overall predictive power of 83.2%, with seven of the eleven independent variables being effective on the adoption of double cropping. LGR indicated an overall predictive power of 87.6%, with eight of the eleven independent variables being effective on the adoption of double-rice cropping. ANNs showed higher power than LGR and LDA in predicting the adoption of double cropping. Based on all three methods used for analysis, the most important independent variables were social participation and area under cultivation (positive factors) as well as distance to the agricultural service center and family members (negative factors). Establishment of cooperatives or other kinds of farmers’ associations to foster social participation could motivate adoption of double cropping, particularly among small-scale farmers. To increase agricultural services, more local centers should be created in rural areas. The government should promote double cropping through effective incentives and technology transfer to small-scale farmers.  相似文献   

First records of the ash whitefly Siphoninus phillyreae Haliday (Hemiptera,Aleyrodidae) in Belgium     

R. Clymans  C. de Schaetzen  M. Jansen  T. Belien  D. Bylemans 《EPPO Bulletin》2019,49(3):564-566

In recent years, a whitefly species has become more abundant in Belgian pear orchards, and a survey over six locations in the province of Limburg in 2017 showed it to be exclusively Siphoninus phillyreae Haliday, the ash whitefly. Although the puparia of the species are fairly easy to recognize in the field, S. phillyreae most probably has previously been overlooked but present in Belgium. Although the species is an important pest in some parts of the world, so far no significant damage has been observed in Belgian pear orchards. This is the first report of this pest in Belgium.  相似文献   

Frog communities and wetland condition: relationships with grazing by domestic livestock along an Australian floodplain river     

Amy Jansen  Michael Healey 《Biological conservation》2003,109(2):207-219

Frogs are in decline worldwide, and are known to be sensitive indicators of environmental change. Floodplains of the Murray-Darling Basin in southeastern Australia have been altered in many ways by livestock grazing, by the introduction of exotic fish, and by changes to flooding regimes. These changes have led to declines in wetland condition and hence to the availability of habitat for wetland frogs. This study examined relationships between frogs, wetland condition and livestock grazing intensity at 26 wetlands on the floodplain of the Murrumbidgee River. Frog communities, species richness, and some individual species of frogs declined with increased grazing intensity. Wetland condition also declined with increased grazing intensity, particularly the aquatic vegetation and water quality components. There were clear relationships between frog communities and wetland condition, with several taxa responding to aquatic and fringing vegetation components of wetland condition. Thus, grazing intensity appeared to influence frog communities through changes in wetland habitat quality, particularly the vegetation. Reduced stocking rates may result in improved wetland condition and more diverse frog communities. River management to provide natural seasonal inundation of floodplain wetlands may also enhance wetland condition, frog activity and reproductive success.  相似文献   

Non‐target screening of leaf litter‐derived dissolved organic matter using liquid chromatography coupled to high‐resolution mass spectrometry (LC‐QTOF‐MS)     

Olaf Brock  Rick Helmus  Karsten Kalbitz  Boris Jansen 《European Journal of Soil Science》2020,71(3):420-432

  相似文献   

Fat feeding increases equine heparin-released lipoprotein lipase activity     

Geelen SN  Jansen WL  Sloet van Oldruitenborgh-Oosterbaan MM  Breukink HJ  Beynen AC 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(5):478-481

The aim of this study was to establish the dose-response relationship between fat intake and heparin-released plasma lipoprotein lipase (LPL) activity in horses. Eight mature trotters were fed 4 rations with different fat levels (3.0, 5.0, 7.7, or 10.8% fat in the dry matter) according to a 4 X 4 Latin square design. The experimental rations consisted of hay and different concentrates; the concentrates and hay were given in a 3:1 ratio on an energy basis. Soybean oil was added to the concentrates at the expense of isoenergetic amounts of glucose. Blood samples were taken at the end of each dietary period, which lasted 3 weeks. Fat feeding was found to increase heparin-released plasma LPL activity in a dose-dependent fashion. When the data from this study and previous studies were combined it was calculated that an increase in fat intake by 1 g/kg dry matter is associated with an increase in LPL activity by 0.98 micromol fatty acid released-mL(-1) x h(-1). Fat feeding raised the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, and phospholipids. Diet did not have a statistically significant effect on plasma triacylglycerol concentrations. The results are discussed in the light of the possible enhancing effect of fat feeding on the oxidative capacity of skeletal muscle.  相似文献