Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Derivation of the economic value of R0 for macroparasitic diseases and application to sea lice in salmon
Janssen, Kasper ; Komen, Hans ; Saatkamp, Helmut W. ; Jong, Mart C.M. de; Bijma, Piter - \ 2018
Genetics, Selection, Evolution 50 (2018)1. - ISSN 0999-193X

Background: Macroparasites, such as ticks, lice, and helminths, are a concern in livestock and aquaculture production, and can be controlled by genetic improvement of the host population. Genetic improvement should aim at reducing the rate at which parasites spread across the farmed population. This rate is determined by the basic reproduction ratio, i.e. R 0, which is the appropriate breeding goal trait. This study aims at providing a method to derive the economic value of R 0. Methods: Costs of a disease are the sum of production losses and expenditures on disease control. Genetic improvement of R 0 lowers the loss-expenditure frontier. Its economic effect depends on whether the management strategy is optimized or not. The economic value may be derived either from the reduction in losses with constant expenditures or from the reduction in expenditures with constant losses. Results: R 0 ≤ 1, the economic value of a further reduction is zero because there is no risk of a major epidemic. When R 0 > 1 and management is optimized, the economic value increases with decreasing values of R 0, because both the mean number of parasites per host and frequency of treatments decrease at an increasing rate when R 0 decreases. When R 0 > 1 and management is not optimized, the economic value depends on whether genetic improvement is used for reducing expenditures or losses. For sea lice in salmon, the economic value depends on a reduction in expenditures with constant losses, and is estimated to be 0.065€/unit R 0 /kg production. Discussion: Response to selection for measures of disease prevalence cannot be predicted from quantitative genetic theory alone. Moreover, many studies fail to address the issue of whether genetic improvement results in reduced losses or expenditures. Using R 0 as the breeding goal trait, weighed by its appropriate economic value, avoids these issues. Conclusion: When management is optimized, the economic value increases with decreasing values of R 0 (until the threshold R 0 = 1, where it drops to zero). When management is not optimized, the economic value depends on whether genetic improvement is used for reduced expenditures or production losses. For sea lice in salmon, the economic value is estimated to be 0.065 €/unit R 0 /kg production.

Towards a safe and sustainable poultry production chain
Berghout, Jacqueline ; Roland, Wibke ; Vollebregt, Martijntje ; Koene, Miriam ; Jong, Ingrid de - \ 2018
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research report 1126) - 79
Seroprevalence and risk factors of lumpy skin disease in Ethiopia
Molla, Wassie ; Frankena, Klaas ; Gari, Getachew ; Kidane, Menbere ; Shegu, Dereje ; Jong, Mart C.M. de - \ 2018
Preventive Veterinary Medicine 160 (2018). - ISSN 0167-5877 - p. 99 - 104.
Capripoxvirus - Cattle - Ethiopia - Lumpy skin disease - Risk factors - Seroprevalence

Lumpy skin disease (LSD) is an acute or inapparent viral disease of cattle which is endemic in many African and Middle East countries. LSD is one of the major transboundary livestock diseases in Ethiopia. A cross-sectional study using multistage cluster sampling was undertaken in central and north-western parts of Ethiopia with the objectives to estimate seroprevalence and to identify and quantify risk factors contributing to the occurrence of the disease. A total of 2386 cattle sera were sampled from 605 herds and 30 clusters (kebeles) located in 10 districts and tested for presence of LSD virus antibodies using virus neutralization test. All the serum samples were collected from cattle having no history of LSD vaccination. The overall animal level and herd level apparent seroprevalences were 25.4% (95% CI: 23.7–27.2) and 48.9% (95% CI: 44.9-52.9), respectively and varied significantly between districts. The true animal level and herd level prevalences were estimated as 26.5% (95% CI: 24.7–28.3) and 52.6% (95% CI: 48.3–56.9), respectively. At animal level, adult age (OR = 2.44 (95% CI: 1.67–3.55) compared to calf), contact with other animals (OR = 0.41 (95% CI: 0.23-0.74), compared to no contact) and presence of water bodies (OR = 1.61 (95% CI: 1.03–2.52), compared to no such bodies) were identified as the most important risk factors in relation to testing LSD positive. The putative risk factors altitude, breed, sex, and presence of animal trade route showed no significant association with LSD sero-status. Generally, cattle population with many adult animals and that live in wet areas are at highest risk, whereas cattle in frequent contact with other animals and animal species have lower risk, potentially due to a dilution effect of vectors.

The Socio-Economic Impact of Extreme Precipitation and Flooding on Forest Livelihoods : Evidence from the Bolivian Amazon
Bauer, T. ; Ingram, V. ; Jong, W.D. de; Arts, B. - \ 2018
International Forestry Review 20 (2018)3. - ISSN 1465-5489 - p. 314 - 331.
climate change - extreme weather events - forest dependence - forest livelihoods - social-ecological systems

In early 2014, unprecedentedly heavy rainfall led to a flood in northern lowland Bolivia affecting the livelihoods of thousands of people relying on ecosystem services and climate sensitive sectors for their daily livelihood. Based on a case study of 50 households from indigenous forest communities living in the TCO Tacana I, ex-ante and ex-post household data were collected to obtain insights into the economic performance, livelihood strategy changes and role of forest products in the direct aftermath of the extreme weather event. A negative impact on natural resource dependent livelihood strategies was found as an immediate consequence. However, most households had recovered just one year later. There was no increase in the use of forest products to mitigate immediate income shortages. A typical high contribution of forest products to household income from before the flood continued afterwards. This article contributes to understanding of livelihood-based efforts of people living in tropical lowland forests to adapt to weather extremes.

Release of major peanut allergens from their matrix under various pH and simulated saliva conditions—Ara h2 and ara h6 are readily bio-accessible
Koppelman, Stef J. ; Smits, Mieke ; Tomassen, Monic ; Jong, Govardus A.H. De; Baumert, Joe ; Taylor, Steve L. ; Witkamp, Renger ; Veldman, Robert Jan ; Pieters, Raymond ; Wichers, Harry - \ 2018
Nutrients 10 (2018)9. - ISSN 2072-6643
Allergen - Arachis hypogaea - Bio-accessibility - Peanut - Saliva

The oral mucosa is the first immune tissue that encounters allergens upon ingestion of food. We hypothesized that the bio-accessibility of allergens at this stage may be a key determinant for sensitization. Light roasted peanut flour was suspended at various pH in buffers mimicking saliva. Protein concentrations and allergens profiles were determined in the supernatants. Peanut protein solubility was poor in the pH range between 3 and 6, while at a low pH (1.5) and at moderately high pHs (>8), it increased. In the pH range of saliva, between 6.5 and 8.5, the allergens Ara h2 and Ara h6 were readily released, whereas Ara h1 and Ara h3 were poorly released. Increasing the pH from 6.5 to 8.5 slightly increased the release of Ara h1 and Ara h3, but the recovery remained low (approximately 20%) compared to that of Ara h2 and Ara h6 (approximately 100% and 65%, respectively). This remarkable difference in the extraction kinetics suggests that Ara h2 and Ara h6 are the first allergens an individual is exposed to upon ingestion of peanut-containing food. We conclude that the peanut allergens Ara h2 and Ara h6 are quickly bio-accessible in the mouth, potentially explaining their extraordinary allergenicity.

Hergebruik ijzerrijk drinkwaterslib biedt kansen voor natuurontwikkeling
Fujita, Y. ; Dorland, E. ; Chardon, W. ; Jong, A.L. de - \ 2018
Vakblad Natuur Bos Landschap (2018)143. - ISSN 1572-7610 - p. 20 - 23.
Hoge fosfaatbeschikbaarheid in voormalige landbouwpercelen belemmert natuurbeheerders bij het omvormen van deze terreinen naar natuurgebieden. Het opbrengen van ijzerrijk drinkwaterslib verlaagt de fosforbeschikbaarheid en lijkt daarom een goed alternatief voor gronden waar afgraven van de fosfaatrijke toplaag geen optie is.
Agent-based modelling of socio-ecological systems : Models, projects and ontologies
Gotts, Nicholas M. ; Voorn, George A.K. van; Polhill, J.G. ; Jong, Eline de; Edmonds, Bruce ; Hofstede, Gert Jan ; Meyer, Ruth - \ 2018
Ecological Complexity (2018). - ISSN 1476-945X - 15 p.
Agent-based model - Complexity - Ontology - Socio-ecological system

Socio-Ecological Systems (SESs) are the systems in which our everyday lives are embedded, so understanding them is important. The complex properties of such systems make modelling an indispensable tool for their description and analysis. Human actors play a pivotal role in SESs, but their interactions with each other and their environment are often underrepresented in SES modelling. We argue that more attention should be given to social aspects in models of SESs, but this entails additional kinds of complexity. Modelling choices need to be as transparent as possible, and to be based on analysis of the purposes and limitations of modelling. We recommend thinking in terms of modelling projects rather than single models. Such a project may involve multiple models adopting different modelling methods. We argue that agent-based models (ABMs) are an essential tool in an SES modelling project, but their expressivity, which is their major advantage, also produces problems with model transparency and validation. We propose the use of formal ontologies to make the structure and meaning of models as explicit as possible, facilitating model design, implementation, assessment, comparison and extension.

Oesterdam sand nourishment : Ecological and morphological development of a local sand nourishment
Boersema, Matthijs P. ; Werf, Jebbe van der; Salvador de Paiva, João N. ; Brink, Anneke M. van den; Soissons, Laura ; Walles, Brenda ; Bouma, Tjeerd J. ; Vet, P.L.M. de; Ysebaert, Tom J.W. ; Paree, Edwin ; Bijleveld, Mariska ; Zanten, Eric van; Westenbrugge, Kees van; Stronkhorst, Joost ; Jong, Dick de - \ 2018
Vlissingen : Centre of Expertise Delta Technology - 78
Europees Hof remt kwekers vanwege genetische modificatie
Smulders, Rene - \ 2018

smulders

Landscape planning-paving theway for effective conservation of forest biodiversity and a diverse forestry?
Michanek, Gabriel ; Bostedt, Göran ; Ekvall, Hans ; Forsberg, Maria ; Hof, Anouschka R. ; Jong, Johnny de; Rudolphi, Jörgen ; Zabel, Astrid - \ 2018
Forests 9 (2018)9. - ISSN 1999-4907
Aichi targets - Biodiversity - Birds directive - Boreal forest - Compensation - Fragmentation - Habitat protection - Habitats directive - Landscape planning - Tax-fund

Globally, intensive forestry has led to habitat degradation and fragmentation of the forest landscape. Taking Sweden as an example, this development is contradictory to international commitments, EU obligations, and to the fulfillment of the Parliament's environmental quality objective "Living Forests", which according to Naturvårdsverket (The Swedish Environmental Protection Agency) will not be achieved in 2020 as stipulated. One important reason for the implementation deficit is the fragmented forestry management. In a forest landscape, felling and other measures are conducted at different times on separate forest stands (often relatively small units) by different operators. Consequently, the authorities take case by case decisions on felling restrictions for conservation purposes. In contrast, conservation biology research indicates a need for a broad geographical and strategical approach in order to, in good time, select the most appropriate habitats for conservation and to provide for a functioning connectivity between different habitats. In line with the EU Commission, we argue that landscape forestry planning could be a useful instrument to achieve ecological functionality in a large area. Landscape planning may also contribute to the fulfilment of Sweden's climate and energy policy, by indicating forest areas with insignificant conservation values, where intensive forestry may be performed for biomass production etc. Forest owners should be involved in the planning and would, under certain circumstances, be entitled to compensation. As state resources for providing compensation are scarce, an alternative could be to introduce a tax-fund system within the forestry sector. Such a system may open for voluntary agreements between forest owners for the protection of habitats within a large area.

Normenboek Natuur, Bos en Landschap 2018 : Tijd- en onkostennormen voor inrichting en beheer van natuurterreinen, bossen en landschapselementen
Raffe, J.K. van; Jong, J.J. de - \ 2018
Wageningen Environmental Research
Kosten en baten bijvriendelijk beheer
Jong, A. de; Korthof, H. ; Piepers, A. ; Rosaria, M. - \ 2018
Amsterdam : Groene Cirkels - 19
Deze brochure is bedoeld om ambtenaren en bestuurders te inspireren in hun gemeente aan de slag te gaan met bijvriendelijk beheer.
The intractable challenge of evaluating cattle vaccination as a control for bovine tuberculosis
Conlan, Andrew James Kerr ; Vordermeier, Martin ; Jong, Mart C.M. de; Wood, James L.N. - \ 2018
eLife 7 (2018). - ISSN 2050-084X

Vaccination of cattle against bovine Tuberculosis (bTB) has been a long-term policy objective for countries where disease continues to persist despite costly test-and-slaughter programs. The potential use of vaccination within the European Union has been linked to a need for field evaluation of any prospective vaccine and the impact of vaccination on the rate of transmission of bTB. We calculate that estimation of the direct protection of BCG could be achieved with 100 herds, but over 500 herds would be necessary to demonstrate an economic benefit for farmers whose costs are dominated by testing and associated herd restrictions. However, the low and variable attack rate in GB herds means field trials are unlikely to be able to discern any impact of vaccination on transmission. In contrast, experimental natural transmission studies could provide robust evaluation of both the efficacy and mode of action of vaccination using as few as 200 animals.

Aardappeldemodag 2018 wil sterke schakels verbinden
Ampt-de Jong, Marieke ; Mol-van de Erve, Leanne ; Tramper, Marcel - \ 2018
"Sterke schakels verbinden" : Aardappel Demodag. Officiële catalogus
Ampt-de Jong, Marieke ; Mol-van de Erve, Leanne ; Tramper, M. ; Brouwer, T.A. - \ 2018
Aardappelwereld 72 (2018)8. - ISSN 0169-653X - p. 43 - 81.
Local dornase alfa treatment reduces NETs-induced airway obstruction during severe RSV infection
Cortjens, Bart ; Jong, Rineke de; Bonsing, Judith G. ; Woensel, Job B.M. Van; Antonis, Adriaan F.G. ; Bem, Reinout A. - \ 2018
Thorax 73 (2018)6. - ISSN 0040-6376 - p. 578 - 580.
infection control - innate immunity - neutrophil biology - paediatric lung disaese - respiratory infection - viral infection

Respiratory syncytial virus (RSV) infection is characterised by airway obstruction with mucus plugs, containing DNA networks in the form of neutrophil extracellular traps (NETs). We investigated the effect of dornase alfa on histopathological NETs-induced airway obstruction and viral load in an age-relevant calf model of severe bovine RSV disease. As compared with the control animals, dornase alfa treatment resulted in a strong reduction of NETs-induced airway obstruction. Viral load in the lower respiratory tract was not different between the two groups. We conclude that NETs form a relevant target for treatment of airway obstruction in severe RSV disease.

Effects of a commercial broiler enrichment programme with or without natural light on behaviour and other welfare indicators
Jong, I.C. de; Gunnink, H. - \ 2018
Animal (2018). - ISSN 1751-7311 - 8 p.
activity - bales - chickens - exploration - perches

Commercial broiler production systems based on market initiatives to improve animal welfare beyond minimum legal requirements have emerged in several European countries. A common factor in the ‘higher welfare’ indoor systems is the application of environmental enrichment, with or without natural light, to promote locomotor activity and natural behaviours of the broiler chickens. In the current study, we evaluated the effects of a commercial enrichment programme for fast-growing indoor-housed broiler chickens, with or without natural light entering the broiler house. Enrichment materials were selected in relation to perceived minimal hygiene risk and ease of cleaning in between production cycles. Selected enrichments were a combination of wood shavings bales (1.5 bale/1000 chickens), round metal perches (2.7 m/1000 chickens) and metal chains as pecking objects (1/1000 chickens). Three treatments were studied: control (C) without enrichment and natural light, enriched (E) with enrichments as previously defined but without natural light and enriched plus natural light (EL) with enrichments as previously defined and natural light entrance. The experiment was carried out during five subsequent production cycles on one commercial broiler farm with three identical houses. EL could only be assigned to the middle house that was equipped with roof windows (light entrance area: 3% of floor space). C and E were in the two outer houses (alternated in between production cycles). Behaviour was observed during daytime at days 25 and 39 of age by scan sampling. Lameness, footpad dermatitis, hock burn, cleanliness and injuries were scored at the same ages, in addition to the response of the chickens to a novel object. Results showed that the treatments only affected broiler behaviour. E flocks showed significantly more resting as compared with EL and C. EL flocks showed significantly more walking, exploration and foraging behaviour as compared with E and C. Thus, broiler activity was highest in the EL treatment and lowest in the E treatment, with the C treatment in between. No treatment effects were found on the other welfare indicators and only a few tendencies for treatment effects were found for the novel object test, with E birds tending to be more reluctant to approach the object as compared with EL and C birds. We concluded that providing environmental enrichment and natural light-stimulated activity and natural behaviours in broiler chickens, whereas providing enrichment only seemed to have the opposite effect as compared with control flocks without enrichment.

Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs
Navarro, Diego M.D.L. ; Bruininx, Erik M.A.M. ; Jong, Lineke de; Stein, Hans H. - \ 2018
Journal of Animal Science 96 (2018)6. - ISSN 0021-8812 - p. 2265 - 2277.
Correlation - Digestibility - Energy - Physicochemical characteristics - Pigs - Total dietary fiber

Effects of physicochemical characteristics of feed ingredients on DE and ME and apparent total tract digestibility (ATTD) of GE, DM, and nutrients were determined in growing pigs using ingredients with different ratios between insoluble dietary fiber (IDF) and soluble dietary fiber (SDF). Eighty growing barrows (BW: 48.41 ± 1.50 kg) were allotted to a randomized complete block design with 10 diets and eight replicate pigs per diet. Dietary treatments included a corn-based diet, a wheat-based diet, a corn–soybean meal (SBM) diet, and seven diets based on a mixture of the corn–SBM diet and canola meal, distillers dried grains with solubles (DDGS), corn germ meal (CGM), copra expellers, sugar beet pulp (SBP), synthetic cellulose, or pectin. Values for the ATTD of DM and nutrients were also compared with the in vitro digestibility of GE, DM, and nutrients. Results indicated that the ATTD of GE was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, and synthetic cellulose, but not different from corn, SBM, or pectin. SBM had greater (P < 0.05) DE and ME (DM basis) compared with all other ingredients. The concentration of ME (DM basis) was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, synthetic cellulose, and pectin, but not different from corn. Stronger correlations between total dietary fiber (TDF) and DE and ME than between ADF or NDF and DE and ME were observed, indicating that TDF can be used to more accurately predict DE and ME than values for NDF or ADF. The DE, ME, and the ATTD of DM in ingredients were positively correlated (P < 0.05) with in vitro ATTD of DM, indicating that the in vitro procedure may be used to estimate DE and ME in feed ingredients. Swelling and water-binding capacity were positively correlated (P < 0.05) with the ATTD of IDF, TDF, non-starch polysaccharides (NSP), and insoluble NSP, and viscosity was positively correlated (P < 0.05) with the ATTD of NDF, IDF, and insoluble NSP, indicating that some physical characteristics may influence digestibility of fiber. However, physical characteristics of feed ingredients were not correlated with the concentration of DE and ME, which indicates that these parameters do not influence in vivo energy digestibility in feed ingredients. It is concluded that the DE and ME in feed ingredients may be predicted from some chemical constituents and from in vitro digestibility of DM, but not from physical characteristics.

Reducing damping-off problems in eggplant (Solanum melongena L.) : A participatory testing of nursery management in Bangladesh
Nahar, Naznin ; Islam, Md Rashidul ; Uddin, Mohammad Mahir ; Jong, Peter de; Struik, Paul C. ; Stomph, Tjeerd Jan - \ 2018
Crop Protection 112 (2018). - ISSN 0261-2194 - p. 177 - 186.
Damping-off - Healthy seedlings - Integrated pest management - Seed treatment - Soil treatment - Source of pathogens

Eggplant seedling production in homestead nurseries of farmers in Jamalpur (Bangladesh) is greatly compromised by damping-off. Therefore, farmers often do not have enough seedlings to transplant. Effective treatments of soil and seed to reduce disease pressure in the nurseries are available but little is known on the relative contributions of soil-borne and seed-borne pathogens to damping-off and on how nursery management can integrate management options under farmers’ conditions. A 2-year nursery study was conducted in consecutive seasons, jointly with farmers and using farmers’ preserved seed and farmers’ nurseries subject to damping-off problems. Year 1 involved a single nursery, Year 2 nine nurseries. The following treatments were tested: Trichoderma harzianum as soil amendment combined with seed treatment using either hot water or Carbendazim and farmers’ conventional practice: curative spraying after appearance of damping-off. In Year 1, a control (no intervention) treatment was also included. Emergence of seedlings, incidence of damping-off, seedling performance variables and farmers’ appreciation of seedling vigour were recorded. Soil treatment with T. harzianum combined with seed treatment with hot water increased seedling emergence and produced 25–64 percentage points more healthy seedlings than farmers’ conventional practice. This combined treatment also improved seedling performance (height, root length, lateral root development), and reduced stem girdling, a symptom associated with disease infection of transplants. To determine the contributions of nursery soil and farmers’ seed to damping-off, blotter and in vitro studies in the laboratory and tray studies in a screen house were performed. Soil proved to be the major pathogen source and treating nursery soil with T. harzianum had the largest positive effect on seedling performance, both reducing damping-off and enhancing seedling growth.

Van plaatsingsruimte naar bemestingsproducten : de sociale inkleuring van samenwerking in de mestmarkt
Buurma, Jan ; Jong, Daniël de - \ 2018
Wageningen : Wageningen Economic Research (Wageningen Economic Research rapport 2018-028) - ISBN 9789463437783 - 41
Dit rapport beschrijft een inhoudsanalyse - wie zegt wat, tegen wie, waarom en hoe? - van 100 artikelen uit Boerderij Vandaag over de mestmarkt en de akkerbouw uit de periode 2005-2016. De artikelen over de samenwerking tussen akkerbouw en veehouderij zijn beschreven als ware het een theatervoorstelling waarin de stakeholders elkaar bestookten met beelden en tegenbeelden. De theatervoorstelling laat een geleidelijke verschuiving zien van ‘kopen van plaatsingsruimte’ naar ‘leveren van bemestingsproducten’. Het rapport wordt afgesloten met aanbevelingen voor verdere kennisontwikkeling rond bodemverbetering en nieuwe opties voor samenwerking tussen akkerbouw en veehouderij.
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