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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    Genetic improvement of longevity in dairy cows
    Pelt, Mathijs van - \ 2017
    Wageningen University. Promotor(en): Roel Veerkamp, co-promotor(en): T.H.E. Meuwissen. - Wageningen : Wageningen University - ISBN 9789463430821 - 188
    dairy cows - longevity - genetic improvement - breeding value - genetic analysis - survival - animal models - animal genetics - melkkoeien - gebruiksduur - genetische verbetering - fokwaarde - genetische analyse - overleving - diermodellen - diergenetica

    Improving longevity helps to increase the profit of the farmer, and it is seen as an important measure of improved animal welfare and sustainability of the sector. Breeding values for longevity have been published since in 1999 in the Netherlands. For AI-companies and farmers it is necessary that breeding values are accurately estimated and will remain stable for the rest of life. However, current breeding values for longevity of bulls seem to fluctuate more than expected. The main aim of this thesis was to revisit the genetics of longevity and develop a genetic evaluation model for longevity, where breeding values reflect the true breeding value quicker during early life and therefore breeding values become more stable. Genetic parameters were estimated for survival up to 72 months after first calving with a random regression model (RRM). Survival rates were higher in early life than later in life (99 vs. 95%). Survival was genetically not the same trait across the entire lifespan, because genetic correlations differ from unity between different time intervals, especially when intervals were further apart. Survival in the first year after first calving was investigated more in depth. Survival of heifers has improved considerably in the past 25 years, initially due to the focus on a high milk production. More recently, the importance of a high milk production for survival has been reduced. Therefore functional survival was defined as survival adjusted for within-herd production level. For survival the optimum age at first calving was around 24 months, whereas for functional survival calving before 24 months resulted in a higher survival. Over years, genetic correlations between survival in different 5-yr intervals were below unity, whereas for functional survival genetic correlations did not indicate that survival changed over years. This suggested that a genetic evaluation using historical data should analyze functional survival rather than survival. A new genetic evaluation system for longevity was developed based on a RRM analyzing functional survival. Based on the correlation between the first breeding value of a bull and his later breeding values, the ranking of bulls was shown to be more stable for RRM than the current genetic evaluation. Bias in breeding value was observed, mainly for bulls with a large proportion of living daughters. Adjusting for within-herd production level reduced this bias in the breeding values greatly. Before implementing this new model for genetic evaluation, the cause of this bias needs to be further investigated.

    Overleving van discard platvis: vaststellen en verhogen
    Marlen, B. van; Molenaar, P. ; Reijden, K.J. van der; Goudswaard, P.C. ; Bol, R.A. ; Glorius, S.T. ; Theunynck, R. ; Uhlmann, S.S. - \ 2016
    IMARES (Rapport / IMARES C180/15) - 116
    pleuronectiformes - overleving - discards - zeevisserij - visserijbeheer - nederland - pleuronectiformes - survival - discards - marine fisheries - fishery management - netherlands
    Consequences of discard survival under the landing obligation : Reporting validation and reprocessing project outcomes of "demersal discard processing"
    Verkempynck, R. ; Machiels, M.A.M. - \ 2015
    IJmuiden : IMARES (Report / IMARES C176/15) - 16
    discards - bycatch - demersal fisheries - demersal fishes - survival - solea - plaice - discards - bijvangst - demersale visserij - demersale vissen - overleving - solea - schol
    This report describes the results of a short and medium term forecast over the period 2016-2019 given different scenarios of discard survival rates (10-50%) of North Sea plaice and North Sea sole. Additionally, average value of landings over the year 2019 is calculated per scenario using the landings derived from the biomass and the average price per kg of both stocks. Potential loss in average gross revenue from value of landings can be inferred from these.
    Hartpillen maken gezond eten niet overbodig
    Ramaker, R. ; Sijtsma, F.P.C. - \ 2015
    Resource: weekblad voor Wageningen UR 10 (2015)7. - ISSN 1874-3625 - p. 9 - 9.
    hartziekten - patiënten - gezondheidsvoedsel - dieetadvisering - voeding en gezondheid - overleving - heart diseases - patients - health foods - diet counseling - nutrition and health - survival
    Hartpatiënten hebben een kleinere kans te overlijden naarmate ze gezonder eten, zelfs als ze de beste medicijnencocktail krijgen. Dat stelt Femke Sijtsma in haar proefschrift. Deze uitkomsten laten volgens Sijtsma zien dat gezonde voeding een verschil blijft maken, ook naast de beste zorg met bijvoorbeeld bloeddrukverlagers, cholesterolverlagers en antistollingsmiddelen.
    Evaluation of the Dutch Eel Management Plan 2015: status of the eel population in the periods 2005 - 2007, 2008 - 2010 and 2011 - 2013
    Wolfshaar, K.E. van de; Tien, N.S.H. ; Griffioen, A.B. ; Winter, H.V. ; Graaf, M. de - \ 2015
    IJmuiden : IMARES Wageningen UR (Report / IMARES Wageningen UR C078/15) - 104
    european eels - palingen - visserijbeheer - nederland - visbestand - overleving - visvangsten - ecologisch herstel - eu regelingen - anguillidae - european eels - eels - fishery management - netherlands - fishery resources - survival - fish catches - ecological restoration - eu regulations - anguillidae
    Evaluatie van het Nederlandse aalbeheerplan: maatregelen hebben in eerste instantie geleid tot een substantiële verbetering van de overleving tussen de perioden 2005-2007 en 2008-2010 gevolgd door een bescheiden verbetering in overleving tussen de perioden 2008-2010 en 2011-2013; positieve effecten op de aalpopulatie kunnen pas na vele jaren zichtbaar worden en blijven onzeker, omdat de aal pas na vele jaren terug zwemt naar zee om zich voort te planten en omdat niet goed bekend is welke de oorzaken zijn van de achteruitgang in de aalpopulatie.
    Control of Pig Reproduction IX
    Rodriguez-Martinez, H. ; Soede, N.M. ; Flowers, W.L. - \ 2013
    Leicestershire, United Kingdom : Context Products Ltd (Society of Reproduction and Fertility volume 68) - ISBN 9781899043484 - 345
    varkens - geslachtelijke voortplanting - gameten - embryo's - kunstmatige inseminatie - embryotransplantatie - zwangerschap - partus - pasgeborenen - biggen - overleving - biotechnologie - metabolomica - eiwitexpressieanalyse - kunstmatige selectie - pigs - sexual reproduction - gametes - embryos - artificial insemination - embryo transfer - pregnancy - parturition - neonates - piglets - survival - biotechnology - metabolomics - proteomics - artificial selection
    Immunogenetic analysis of natural antibody isotypes in laying hens
    Sun, Y. - \ 2013
    Wageningen University. Promotor(en): Johan van Arendonk, co-promotor(en): Jan van der Poel; Henk Parmentier. - S.l. : s.n. - ISBN 9789461736796 - 192
    hennen - pluimvee - immunogenetica - genetische analyse - antilichamen - isotopen - overleving - genetische parameters - verenpikken - dierveredeling - hens - poultry - immunogenetics - genetic analysis - antibodies - isotopes - survival - genetic parameters - feather pecking - animal breeding

    Worldwide, especially in Europe, poultry industry is undergoing important changes including ban of the battery housing system and prohibition of beak trimming. The former can facilitate more spread of infectious diseases, and the latter will contribute to higher mortality because of severe feather pecking. Furthermore, given the growing social concern about food safety and human health, abundant use of antibiotics will either be prohibited or restricted. These changes further emphasize the importance of implementing general disease resistance in layers breeding goals next to maintaining high production. The aim of this thesis was to find proper traits which are associated with laying hens survival, and reveal genetic architecture and background underlying the traits. Natural antibody (NAb), which are the antibodies present in normal healthy animals in the absence of a deliberate antigen exposure are an important humoral part of innate immunity. The relationships between survival and NAb isotype titers were firstly investigated by the logistic regression analysis in a population of laying hens from 12 purebred lines. The results indicated that NAb, especially the IgM isotype titers at young age was predictive for survival of a laying period. Genetic parameters of NAb isotypes IgM and IgG titers were estimated in the same population. The estimation showed that both NAb isotypes are moderate to high heritable traits which were possible to breed for. An association study revealed different QTL or SNP markers for NAb isotypes titers. The majority of the commercial laying hens are crossbred. Therefore, the relationships between NAb isotype titers and survival were further investigated in crossbred laying hens. However, a consistent relationship as in the purebred was not found. This confirmed the speculation that non-health-related causes of mortality (severe feather pecking) overruled the anticipated relationships between NAb isotype titers and survival in birds with intact beaks. Overall, the present studies indicate that it is possible to implement NAb especially the IgM isotype titers into the breeding goals of laying hens to improve the health-related survival.

    Eggsposed : impact of maternally transferred POPs on fish early life development
    Foekema, E.M. - \ 2013
    Wageningen University. Promotor(en): Tinka Murk. - S.l. : s.n. - ISBN 9789461736659 - 208
    vissen - persistente organische verontreinigende stoffen - maternale effecten - visseneieren - larven - biologische ontwikkeling - overleving - marien milieu - verontreiniging - ecotoxicologie - fishes - persistent organic pollutants - maternal effects - fish eggs - larvae - biological development - survival - marine environment - pollution - ecotoxicology

    Persistent organic pollutants (POP), with well-known representatives as polychlorinated biphenyls (PCBs), dioxins, and brominated flame retardants as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCD), are still globally present in the marine environment, This despite the substantial reduction of application and emission that was achieved during the last decades. Apart from their persistency these compounds share low water solubility and a high lipophilicity which make that the highest concentrations in the aquatic environment are found in the organic matrix of sediments and in biota. Dissolved water concentrations are low. Hence, intake of contaminated food items forms the major source for POPs exposure of aquatic organisms, and through biomagnification the highest concentrations can be found in the tissue of top predators. POPs have the potency to cause a variety of toxic effects, among which endocrine disruption and teratogenic effects that especially apply to early life stages. As the early life stages of most fish species develop suspended in the water column, exposure to POPs may be considered relatively low, at least until the larvae start feeding after yolk absorption. However, POPs accumulated in the tissue of the mother are transferred to the eggs. The research presented in this thesis aims at the determination of the impact of such maternally transferred POPs on development and survival of fish early life stages, in order to assess if this exposure route can significantly impact the development of a fish population at current environmental concentrations, especially in combination with high fishing pressure.

    For this purpose a bioassay was developed with the common sole (Solea solea). The advantages for this research of this new bioassay above standard fish early life stage (ELS) tests are that sole is a native West European species that as all flatfishes undergoes an obvious metamorphosis. The test set-up includes this metamorphosis that is thyroid hormone mediated and therefore expected to be easily disrupted by POPs, based on research with amphibians. The prolonged Early Life Stage test (p-ELS) with sole is presented in chapter 2. Early life stages were exposed to a concentration series of the dioxin-like PCB 126 (3,3',4,4',5-pentachlorobiphenyl) in seawater until 4, 8,10 and 15 days post fertilisation (dpf). Subsequently the development of the larvae was registered under further unexposed conditions. The LC50s at the start of the free-feeding stage (12 dpf) ranged between 39 and 83 ng PCB 126/l depending on exposure duration. After the fish had completed the metamorphosis, the LC50 values ranged between 1.7 and 3.7 ng PCB 126/l for the groups exposed for 4, 8 and 10 dpf respectively. Thus exposure for only 4 days, covering only the egg stage, was sufficient to cause adverse effects during a critical developmental phase two weeks later. This study indicates that ELS fish tests that are terminated shortly after the fish becomes free-feeding underestimate the toxic potential of compounds with low acute toxicity such as PCBs. The internal dosages of these larvae at the end of the exposure, determined by means of an in-vitro gene reporter assays as dioxin-equivalent values (TEQ), revealed an internal lethal concentration, ILC50 of 1 ng TEQ/g lipid, which is within the same order of magnitude as TEQ levels found in fish from highly polluted areas. This suggests that larval survival of fish populations at contaminated sites can be affected by persistent compounds that are accumulated by the female fish and passed on to the eggs.

    Based on these first results the p-ELS test procedure was improved to reach a better control performance. The exposure period was terminated when all larvae had hatched (6 dpf), this in order to mimic exposure through maternal transfer as good as possible without exposing parent fish or manipulation the eggs. In a second test (Chapter 3) the eggs were exposed to a concentration series of methyltriclosan (MTCS), a metabolite of triclosan (TCS) that is commonly used as bactericide in a wide variety of human care products. MTCS and TCS are discharged with waste water, bioaccumulate in fish tissue, and are known to have the potency to disrupt the thyroid hormone system. Mortality occurred in the higher treatment levels until 20 dpf. Indications for thyroid hormone disruption were not observed; all surviving larvae completed metamorphoses without problems. Internal effect concentrations, reached in larvae at the end of the exposure (6 dpf), were 5.8 mg/g lipid weight (lw) and 2.1 mg/g lw for ILC50 and ILC10 respectively. These internal effect concentrations are at least 200 times higher than concentrations that due to maternally transfer can be expected in the eggs of highly exposed fish in a field situation. Our results thus do not indicate a high risk from maternally transferred MTCS for fish at the current field concentrations.

    In order to get more insight in the fate of the POPs in the larvae, in Chapter 4 the existing bioaccumulation model OMEGA was adjusted for sole early life stages and validated with experimental data with PCBs. This study revealed, that tissue concentrations of compounds with log Kow>6, peak in the tissues of developing sole at the end of the yolk-sac stage, when lipid reserves are depleted. As a result, just before the larvae become free feeding, the peak tissue concentrations of the pollutants in the larvae exceed that of the adult fish. This also explains at least partly, the delayed effects that were observed in Chapter 2 (and 5).

    Chapter 5 assesses the likelihood that early life development of fish from contaminated areas is affected by maternally transferred POPs. Following the p-ELS test protocol, effects on sole larvae were determined for the dioxin-like PCB 126, the technical PCB-mixture Arochlor 1254, PBDEs and HBCDs, for an artificial mixture of PCBs and PBDEs, and for ‘field mixtures’ extracted from sole collected from the North Sea and in the contaminated Western Scheldt estuary. As was earlier observed with PCB126 and MTCS, exposure to PCBs, PBDEs and the artificial and field mixtures caused mortality that started to occur shortly after the larvae became free-feeding and continued to increase until the onset of metamorphoses. The effects induced by the field mixtures correlated well with the ∑PCB concentrations in the tissue of the exposed larvae. No indications were found for synergistic effects or for substantial contribution of other (unknown) substances in the field mixtures. HBCD did not induce toxic effects. POP levels in sole from Western Scheldt estuary are about 20 times lower than the ILC50, the larval tissue concentration that produced 50% early life stage mortality. Levels in North Sea sole are an order of a magnitude lower.

    Chapter 6 describes a risk assessment for toxicant induced larval survival for European eel (Anguilla anguilla). Eels are considered sensitive for the effect of POPs that can accumulate to high levels in their lipid rich tissue. During spawning migration without feeding high lipophilic dioxin-like POPs in the eel’s tissue were estimated to increase 1.33 or 2 fold, due to weight loss. As no toxicity data are available for eel larvae, the critical egg concentrations for larval survival was estimated from a sensitivity distribution based on literature data of other species. It was assumed that eel larvae belong to the 5% or 1% most sensitive teleost fish species. Given concentrations of dioxin-like pollutants as reported for European eel, and following the worst case scenarios with respect to sensitivity of the larvae and bio amplification during migration, it can be expected that larvae of eel from highly contaminated locations in The Netherlands and Belgium will experience more than 50% mortality due to maternally transferred dioxin-like toxicants.

    Chapter 7 explores the potential impact of (toxicant induced) early life stage mortality on the population development of sole by application of a simple age structured matrix model. The model is used to explore the population response to a combination of (toxicant induced) larval mortality and fishing-related mortality of mature fish. The results indicate that the impact of larval mortality that occurs before metamorphosis is very low, even in population subject to high fishing pressure. This is the result of the combination of a high fecundity and the fact that the larval mortality occurs before the moment when the number of recruits is limited by the carrying capacity of the nursery areas. When colonising the nursery areas the, until than pelagic sole larvae metamorphose into flatfishes with a benthic life style. The individuals hence concentrate from the three dimensional pelagic environment to a two dimensional benthic environment, which caused density dependent mortality. This concentration of early life stages is typical for flatfish. Mortality that occurs after the nursery areas are populated will have a more pronounced impact on population development. The results further imply that population development of pelagic fish species that do not concentrate in nursery areas, and species with low fecundity is more vulnerable for disturbance through mortality of early life stages.

    Chapter 8 synthesises and discusses the outcome of the research. It is stressed that short term fish tests, often covering only the embryonic development, will underestimate the real risk of lipophilic substances. Toxicity of these substances will peak after yolk sac absorption when these tests have already been ended. When the characteristics of the test substance are known this risk is predictable with for instance the ELS-OMEGA model. However, especially when mixtures of unknown composition (effluents, sediment extracts) are being tested one must realise that the contribution of lipophilic substances may be underestimated in test that are terminated before, or too soon after the fish larvae are free feeding.

    The absence of effects on metamorphosis in our P-ELS test is explained by the prediction of the ELS-OMEGA model that the POPs concentrations in the larvae, had reached too low concentrations at the moment of metamorphoses to disrupt the thyroid hormone system. This was due to passive excretion (for substances with log Kow<6) and growth dilution.

    It must be realised that the experimental set-up that was followed to mimic the effects of maternally transferred POPs does not include potential effects of maternally transferred metabolites of these POPs that can be formed by the parent fish and that are often more toxic than the mother compounds. Also effects of the mother’s condition on the quality of the eggs and epigenetic effects were not included. This implies that the results of the tests as performed in some cases might underestimate the actual effects of these substances.

    The species most vulnerable to the effects of maternally transferred POPs share a high exposure, low fecundity and the absence of density dependent mortality of early life stages. According to these criteria sharks and especially the Greenland shark (Somniosus microcephalus) that is highly exposed to POPs can be considered as highly vulnerable. It is therefore recommended to investigate the actual sensitivity of this species, in order to get more insight in the potential vulnerability of the populations.

    Mosselwad, onderzoeksprogramma voor herstel van mosselbanken in de Waddenzee
    Jansen, J.M. ; Dankers, N.M.J.A. ; Ens, B.J. - \ 2012
    De Levende Natuur 113 (2012)3. - ISSN 0024-1520 - p. 110 - 112.
    mytilus edulis - mossels - overleving - hydrodynamica - ecologisch herstel - asteroidea - aythya - wetenschappelijk onderzoek - waddenzee - mytilus edulis - mussels - survival - hydrodynamics - ecological restoration - asteroidea - aythya - scientific research - wadden sea
    Hoe staat het met de schelpdieren in de Waddenzee? Aan de hand van langjarige tijdreeksen geven we een overzicht van de ontwikkeling van Mossel (Mytilus edulis), Kokkel (Cerastoderma edule), Nonnetje (Macoma balthica) en nieuwkomer de Japanse oester (Crassostrea gigas). Hierbij speelt de vraag welke factoren bepalend zijn voor de aantalsontwikkeling van de verschillende soorten
    Campylobacter jejuni: exposure assessment and hazard characterization : growth, survival and infectivity of Campylobacter jejuni
    Verhoeff-Bakkenes, L. - \ 2012
    Wageningen University. Promotor(en): Marcel Zwietering, co-promotor(en): Rijkelt Beumer; R. de Jonge. - [S.l.] : s.n. - ISBN 9789461731241 - 144
    campylobacter jejuni - groei - overleving - infectiviteit - bacterieziekten - risicoschatting - voedselmicrobiologie - campylobacter jejuni - growth - survival - infectivity - bacterial diseases - risk assessment - food microbiology

    Campylobacter jejuni, a small, curved or spirally shaped highly motile microorganism, is identified as a major cause of bacterial gastroenteritis throughout the world. Serious complications such as the Guillain-Barré syndrome and reactive arthritis might occasionally follow infection. In this thesis data were generated in the fields of hazard characterization and exposure assessment, which were used to identify risk factors for Campylobacter.

    Although C. jejuni is generally seen as an obligate micro-aerophile, in this thesis it was shown that it can grow aerobically in the presence of pyruvate, and growth might also be possible in the presence of other antioxidants. However, as result of the strict minimal growth temperature (30ºC), C. jejuni is still assumed to be generally unable to grow in foods and therefore growth is not considered as a large risk for campylobacteriosis.

    C. jejunican, and does, survive effectively for long periods of time under non-growing conditions in various environments. Temperature is the most influencing factor in survival and survival will be optimal at low temperatures (around 4ºC). As many foods are stored chilled, this will prolong the survival of C. jejuni. Furthermore survival is enhanced at low oxygen conditions, as often present in packaged foods. While the effects of environmental conditions on the survival of C. jejuni have been studied extensively, the knowledge of the effect of environmental factors on the infectivity was scarce. Therefore, the effect of environmental conditions (temperature, medium and atmosphere) on both the survival of C. jejuni and the infectivity of the surviving cells was investigated. We revealed that culturability and infectivity are linearly related. Furthermore, our study on the effect on the infectivity of adding nonculturable C. jejuni cells to culturable cell suspensions, showed nonculturable cells not to be infective (in vitro). Therefore, absence of culturable C. jejuni cells indicates that a product can be regarded as representing a very low risk with respect to campylobacteriosis.

    Food products can be contaminated with Campylobacter during production or afterwards at the consumer’s home. Once contaminated the risk is high that Campylobacter will survive on food products until the moment of consumption, except if the product undergoes an elimination step during preparation, such as heating. The growth requirements for Campylobacter are met in the gastrointestinal tract of warm-blooded animals. As a result especially products of animal origin, like chicken meat and raw milk, are often contaminated by Campylobacter, but also products of non-animal origin, like vegetables and fruits, can be contaminated. Within the exposure assessment cross-contamination in the home, the importance of raw vegetables and fruits as a risk factor for Campylobacter, and the relative importance of chicken meat, raw milk and raw vegetables and fruits were studied.

    The effect of different cross-contamination routes during the preparation of a chicken fruit salad was investigated. It was shown that the mean transfer rate by cross-contamination was 0.12% of the initial number of C. jejunion the chicken fillet, and that the different tested cross-contamination routes; cutlery, cutting board and hands, were equally important. The high prevalence and concentration of C. jejuni on chicken meat, the high percentage of consumers who exhibit improper hygienic and cleaning behaviour, and the significant transfer of Campylobacter during improper food preparation, indicate cross-contamination from raw foods, such as chicken, to other ready-to-eat foods as a large risk factor for Campylobacter infection.

    Fresh produce can become contaminated with C. jejuni during cultivation or processing. Especially vegetables and fruits which are eaten raw may present a risk. In this thesis Dutch data on the prevalence of Campylobacter on raw vegetables and fruits were newly analysed. Thirteen of the 5640 vegetable and fruit samples were Campylobacter positive, resulting in a prevalence of 0.23% (95% confidence interval (Cl): 0.12-0.39%). The prevalence on packaged products was significantly higher than on unpackaged products.

    Finally, the newly acquired data and quantitative literature data on the prevalence and concentration of Campylobacter entering the consumer phase were summarized for three food groups; vegetables and fruit, chicken, and raw milk. These data were used in a quantitative risk assessment model to estimate the exposure and the number of illnesses as result of the consumption of these foods and to compare their relative importance. The prevalence and concentration are low on raw vegetables and fruit, but the quantity of raw vegetables and fruits consumed is very high. In contrast, raw chicken and raw milk show relative high prevalence and concentration levels, but the consumption is low. Despite the differences in parameters, the exposure calculated out of the combination of parameters indicates all these three foods as high risk factors for Campylobacter. So foods which are not heavily contaminated with Campylobacter, but are consumed in large quantities can constitute a similar high risk on Campylobacter infection as foods which are consumed in small quantities but are heavily contaminated with Campylobacter.

    Populatie-dynamisch model voor grauwe ganzen : ontwikkeling model ten behoeve van aantalregulering
    Kleijn, D. ; Baveco, J.M. ; Voslamber, B. ; Lange, H.J. de; Melman, T.C.P. - \ 2011
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2234) - 56
    anser - ganzen - modellen - populatiebiologie - populatiedynamica - overleving - nederland - anser - geese - models - population biology - population dynamics - survival - netherlands
    Dit rapport beschrijft een deel van de werkzaamheden die in het kader van het onderzoeksproject "Populatiebeheer overzomerende (Grauwe) ganzen" in 2009 en 2010 zijn uitgevoerd. Het aantal ganzen dat in Nederland broedt neemt de laatste decennia spectaculair toe. Dit toenemende aantal ganzen veroorzaakt een zodanige maatschappeleijke overlast dat aantalregulerende maatregelen worden overwogen. Het is echter nog onduidelijk welk effect de verschillende maatregelen hebben. Om hier meer inzicht in te krijgen is een ruimtelijk-expliciet, op individu gebaseerd, dichtheidsafhankelijk model ontwikkeld voor de Grauwe gans.
    On the wings of change : species' responses in fragmented landscapes under climate change
    Cormont, A. - \ 2011
    Wageningen University. Promotor(en): Paul Opdam, co-promotor(en): Jana Verboom-Vasiljev; Claire Vos. - [S.l.] : S.n. - ISBN 9789085859574 - 217
    klimaatverandering - weer - verspreiding - overleving - uitsterven - populatiedynamica - landschap - habitatfragmentatie - fauna - lepidoptera - climatic change - weather - dispersal - survival - extinction - population dynamics - landscape - habitat fragmentation - fauna - lepidoptera
    Omdat klimatologische condities bepalen wat geschikt habitat is voor soorten, kan klimaatverandering in de zin van temperatuursstijging ook leiden tot verschuivingen in de verspreiding van soorten. De mogelijkheid van soorten om zich ook daadwerkelijk te vestigen in de nieuwe geschikte habitatgebieden, is afhankelijk van hun reproductiesnelheid en dispersiecapaciteit. Soorten die weinig mobiel zijn, hebben een langere periode nodig om zich te verplaatsen naar locaties met nieuw ontstaan habitat, en óf die soorten deze locaties daadwerkelijk zullen bereiken, hangt af van de mate van habitatfragmentatie en de mate waarin de soorten daar last van hebben.
    Shortlist masterplan wind Effect of pilling noise on the survival of fish larvae (pilot study)
    Bolle, L.J. ; Jong, C.A.F. ; Bierman, S.M. ; Haan, D. de; Huijer, T. ; Kaptein, D. ; Lohman, M. ; Tribuhl, S.V. ; Beek, F.A. van; Damme, C.J.G. van; Berg, F. van den; Heul, J.W. van der; Keeken, O.A. van; Wessels, P. ; Winter, H.V. - \ 2011
    IJmuiden : IMARES (Report / IMARES Wageningen UR C092/11) - 138
    larven - vissen - geluidshinder - overleving - gezondheidsgevaren - diergezondheid - health impact assessment - noordzee - windmolenpark - larvae - fishes - noise pollution - survival - health hazards - animal health - health impact assessment - north sea - wind farms
    Fish can suffer lethal damage to their swim bladder or other organs due to loud impulse sounds such as pile driving noise. However, detailed dose-response studies are still scarce, especially for the early life stages. In view of the rapid extension of offshore wind farms in the North Sea, there is an urgent need to acquire more knowledge on the effects of noise caused by pile driving. This study focussed on the effect of piling noise on the survival of fish larvae.
    Shortlist Masterplan Wind. Effect of pilling noise on the survival of fish larvae( pilot study) progress report
    Bolle, L.J. ; Keeken, O.A. van; Damme, C.J.G. van; Winter, H.V. ; Haan, D. de; Lohman, M. ; Heul, J.W. van der; Huijer, T. - \ 2010
    IJmuiden : IMARES (Report / IMARES Wageningen UR C176/10) - 76
    larven - vissen - geluidshinder - overleving - diergezondheid - gezondheidsgevaren - health impact assessment - noordzee - windmolenpark - larvae - fishes - noise pollution - survival - animal health - health hazards - health impact assessment - north sea - wind farms
    Fish can suffer lethal damage to swimming bladder or other organs due to extreme loud impulse sounds caused by e.g. pile driving (Popper & Hastings 2009). Juvenile and adult fish can actively swim away from a sound source, but planktonic larvae are not able to do this. As a result, fish larvae may suffer more from underwater noise than the older life stages. Despite the many indications for adverse effects, detailed information on the effect of different sound levels on fish is still scarce, especially for the early life stages. Within the framework of the Appropriate Assessment of Dutch offshore wind farms, the effect of piling noise on the southern North Sea population of herring, sole, and plaice larvae was simulated (Prins et al. 2009). For this, an existing larval transport model (Bolle et al. 2005, 2009, Dickey-Collas et al. 2009, Erftemeijer et al. 2009) was expanded with crude assumptions on larval mortality caused by pile driving. The model results were extrapolated to other fish species and older life stages, based on “expertjudgment", in an attempt to assess the effect of offshore piling on the prey availability for birds and marine mammals in Natura 2000 areas (Bos et al. 2009). This assessment involved a large number of uncertainties. The first and most important uncertainty was the range around a piling site in which larval mortality occurs. It was assumed that 100% mortality occurs up to a distance of 1 km from the piling site. However, little is known about larval mortality rates in relation to the level of exposure to piling noise. In general, there is an urgent need to obtain more knowledge on the effect of sound on fish (survival, distribution, and behaviour) during different life stages. More particularly, in view of the rapid extension of offshore wind farms, there is an urgent need to fill the knowledge gap on lethal effects of loud impulse noises caused by pile driving. The broader aim of the current project is to examine the effect of piling noise on the survival of fish larvae. However, within the limited resources and time frame of the Shortlist research programme it is not possible to carry out field experiments, nor is it possible to execute elaborate series of experiments. The first goal within the Shortlist programme is to examine the feasibility of laboratory experiments with pile driving noise and fish larvae. The second goal is to use the laboratory set-up in a pilot study aiming at determining the threshold at which mortality of fish larvae occurs. This shortlist study is limited to laboratory experiments, lethal effects, larvae of 1 species (sole, Solea solea) and 3 series of experiments (trials). The study consists of exposure-effect experiments only; the effects of pile driving at the population level will not be modelled, nor will the results be extrapolated to other species or life stages. The progress to date has been documented in a series of memo’s. These memos are included in this report as Appendices and are summarised in the sections of the report.
    Towards stochastic simulation of crop yield: a case study of fruit set in sweet pepper
    Wubs, A.M. - \ 2010
    Wageningen University. Promotor(en): Leo Marcelis, co-promotor(en): Ep Heuvelink; Lia Hemerik. - [S.l.] : S.n. - ISBN 9789085856993 - 149
    capsicum annuum - paprikapoeder - simulatiemodellen - stochastische modellen - vruchtzetten - abortie (planten) - overleving - source-sink relaties - capsicum annuum - paprika - simulation models - stochastic models - fruit set - abortion (plants) - survival - source sink relations
    Crop growth simulation models are widely used in research and education, and their use in commercial practice is increasing. Usually these models are deterministic: one set of input values always gives the same output of the model. In reality, however, variation exists between plants of the same crop. A simulation model taking this variation into account is therefore more realistic. The aim of this thesis is to introduce a stochastic component into a dynamic crop simulation model. As case study, fruit set in sweet pepper was used, because large variation in fruit set between the plants exists. Competition with fast growing fruits causes abortion of flowers and young fruits, which results in periods with high and low fruit set, and consequently periods of high and low fruit yield. A literature review showed that most factors influencing fruit abortion can be expressed in the terms source and sink strength. Source strength is the supply of assimilates; a higher source strength increases fruit set. Source strength takes into account leaf area, radiation, and CO2 level and temperature. Sink strength is the demand for assimilates of the fruits and vegetative parts. It is quantified by the potential growth rate, i.e. the growth rate under non-limiting assimilate supply. Assimilate demand of the fruits depends on their number, age, and cultivar. If the total fruit sink strength of a plant is low, fruit set is high. Vulnerable for abortion were very small buds, buds close to anthesis and flowers and young fruits up to 14 days after anthesis. An experiment with six Capsicum cultivars with fruit sizes ranging between 20 and 205g fresh weight showed that variation in weekly fruit yield is highly correlated with variation in weekly fruit set. Fruit yield patterns resembled fruit set patterns, with a lag time being equal to the average fruit growth duration. Further investigation showed that the cultivars not only differed in sink strength of the individual fruits, but also that the source-sink ratio above which fruit set occurred was higher in cultivars with larger fruits. In the second half of the thesis, flower and fruit abortion was modelled. Survival analysis was used as the method to derive the abortion function. Source and sink strength were used as the factors influencing abortion. Their effect on the probability of abortion per day was non-linear: at high values of source and sink strength an increase did not further decrease or increase the probability of abortion, respectively. Flowers on the side shoots turned out to have a higher probability of abortion than flowers on the main shoot. Most flowers and young fruits aborted around 100°Cd after anthesis. The obtained function was used in a crop simulation model for sweet pepper. After calibration the model was able to simulate the observed fruit set pattern, although fruit abortion was not properly simulated when low source strength was combined with high sink strength. Validation with three independent data sets gave reasonable to good results. Survival analysis proved to be a good method for introducing stochasticity in crop simulation models. A case study with constant source strength showed asynchronisation of fruit set between the plants, indicating that fluctuations in source strength are an important factor causing synchronisation between individual plants.

    PhD project: Productiviteit van de mosselkweekcyclus in de Waddenzee. Introductie en verkenning data van Mei 2009 tot Februari 2010
    Capelle, J. ; Wijsman, J.W.M. - \ 2010
    Yerseke : IMARES (Rapport / IMARES Wageningen UR C084/10) - 47
    mossels - mosselteelt - onderzoek - groei - overleving - dierlijke productie - zaadproductie - mussels - mussel culture - research - growth - survival - animal production - seed production
    Dit rapport geeft een overzicht van de methodiek en een verkenning van de resultaten van bemonsteringen die zijn uitgevoerd tijdens het eerste jaar voor het PhD project: “de productiviteit van de mosselkweek cyclus in de Waddenzee”. Als onderdeel van dit project zijn mosselen gevolgd van zaad tot veiling. Hiertoe zijn op percelen in de Waddenzee vier maal per jaar metingen verricht aan deze mosselen. Een ruimtelijke indeling op basis van de relatieve Theoretische Productie Waarde (TPW) van de percelen lijkt een goede indicator te zijn voor verschillen in groei en overleving. In de discussie en conclusie worden aanbevelingen gedaan voor nader onderzoek. Het onderzoek zoals het in dit rapport wordt beschreven zal nog twee jaar doorlopen.
    Genetics of survival in cannibalistic laying hens : the contribution of social effects
    Ellen, E.D. - \ 2009
    Wageningen University. Promotor(en): Johan van Arendonk, co-promotor(en): Piter Bijma; M.J. Wade. - [S.l. : S.n. - ISBN 9789085853664 - 168
    pluimvee - hennen - eierproductie - kannibalisme - dierveredeling - fokkerijmethoden - sociale interactie - lijnen - kunstmatige selectie - selectie - mortaliteit - overleving - pluimveehokken - diergenetica - poultry - hens - egg production - cannibalism - animal breeding - animal breeding methods - social interaction - lines - artificial selection - selection - mortality - survival - poultry housing - animal genetics
    Mortality due to cannibalism in laying hens is a worldwide economic and welfare problem occurring in all types of commercial poultry housing systems. Due to prohibition of beak-trimming and the traditional battery system in the European Union in the near future, mortality due to cannibalism in laying hens may increase. To reduce mortality in laying hens, it is possible to use genetic selection. Mortality due to cannibalism, however, depends on social interactions between group members. Traditional selection methods neglect these social interactions, meaning that they ignore the genetic effect an individual has on its group members. These methods are, therefore, not very effective. The main aim of this thesis is to investigate the effect of social interactions on the heritable variance in mortality due to cannibalism in laying hens and to develop a selection method that takes into account social interactions.
    To investigate the effect of social interactions on the heritable variance in mortality due to cannibalism, genetic parameters for direct and associative effects on survival time in three layer lines were estimated. For all three layer lines it was found that social interactions contribute approximately two-third of the heritable variation in survival time. The heritable variation in survival time is, therefore, substantially larger than suggested by the traditional methods currently used in poultry breeding.
    To improve traits affected by social interactions in laying hens, a solution is to select individually housed candidates based on the performance of their full sibs kept in family groups. Theoretical results suggest that this selection method offers good opportunities to improve traits affected by social interactions. A selection experiment was applied aiming to improve mortality due to cannibalism in laying hens using selection based on relatives. After one generation, mortality was 10% lower in the selection line compared to the control. In the second generation, no significant effect was found, which seemed to be related to environmental factors.
    Results in this thesis suggest that prospects for reducing mortality due to cannibalism by means of genetic selection are good. Using selection methods that incorporate social interactions may lead to substantial reduction of one of the major welfare problems in egg production. Further research is needed to investigate the effect of group size and kin recognition on social interactions.


    De relatie tussen gebruiksintensiteit en de kwaliteit van graslanden als foerageerhabitat voor gruttokuikens
    Kleijn, D. ; Dimmers, W.J. ; Kats, R.J.M. van; Melman, T.C.P. - \ 2009
    Wageningen : Alterra (Alterra-rapport 1753) - 38
    limosa limosa - voedingsgedrag - geleedpotigen - graslandbeheer - grondwaterstand - kunstmeststoffen - mortaliteit - overleving - nederland - agrarisch natuurbeheer - weidevogels - friesland - noord-holland - utrecht - limosa limosa - feeding behaviour - arthropods - grassland management - groundwater level - fertilizers - mortality - survival - netherlands - agri-environment schemes - grassland birds - friesland - noord-holland - utrecht
    De huidige studie onderzocht op welke wijze de intensiteit van graslandgebruik het aanbod en de bereikbaarheid van prooidieren (arthropoden) voor gruttokuikens beïnvloedt. De ontwik¬kelingssnelheid van de vegetatie werd daarbij gebruikt als maat voor de landgebruiksintensiteit omdat deze het product is van alle maatregelen die een boer neemt om de productiviteit van de vegetatie te verhogen. De resultaten suggereren dat de vegetatiestructuur de belangrijkste bepalende factor is die de geschiktheid van grasland als foerageerhabitat voor Grutto families bepaalt. Het totale aantal arthropoden nam licht toe met toenemende intensiteit van het landgebruik. De toename in vegetatiehoogte was echter zo groot dat de dichtheid in arthropoden per volume vegetatie afnam met toenemende beheersintensiteit. De dichtere vegetatiestructuur tezamen met de afnemende prooidierdichtheid leidt ertoe dat de energetische kosten van foerageren toenemen bij toenemende beheersintensiteit. Dit duidt erop dat de meest ijle en open vegetaties de meest geschikte foerageerhabitat vormen omdat arthropoden hierin het sterkst geconcentreerd voorkomen en omdat de foerageerkosten het laagst zijn. Voor het creëren van een dergelijke open structuur lijkt onder de huidige omstandigheden het vasthouden van een hoog waterpeil tot en met de kuikenperiode essentieel omdat hiermee onafhankelijk van de voedselrijkdom de vegetatiegroei sterk geremd kan worden. Dit rapport beschrijft een gecombineerde analyse van de data, verzameld in Wormer- en Jisperveld, Gerkesklosster en Ronde Hoep (Kleijn, 2007)
    Risico-analyse van de overlevingskansen van stadia van parasieten in kalvergier uit de intensieve veehouderij
    Borgsteede, F.H.M. - \ 2008
    Lelystad : CVI (CVI / Rapport 08/CVI0079/FBo/AHo) - 9
    parasieten - kalveren - drijfmest - overleving - intensieve veehouderij - risicoschatting - parasitologie - diergezondheid - volksgezondheid - parasites - calves - slurries - survival - intensive livestock farming - risk assessment - parasitology - animal health - public health
    Factoren die de overleving van weidevogelkuikens beïnvloeden
    Teunissen, W. ; Klok, T.C. ; Kleijn, D. ; Schekkerman, H. - \ 2008
    Ede : Directie Kennis, Ministerie van Landbouw, Natuur en Voedselkwaliteit (SOVON nr. 2008/01) - 80
    vogels - onvolwassenheid - overleving - dierecologie - monitoring - weidevogels - agrarisch natuurbeheer - birds - juvenility - survival - animal ecology - monitoring - grassland birds - agri-environment schemes
    Uit onderzoek naar de effectiviteit van het huidige weidevogelbeheer komt telkens naar voren dat er voor de ontwikkeling van een beter beheer op een aantal punten nog onvoldoende kennis aanwezig is over factoren die van belang zijn voor de overleving van weidevogelkuikens. Die ontbrekende kennis spitst zich toe op de invloed die weer, voedsel en beheer op de conditie en daarmee op de overleving van kuikens hebben. Een deel van de vragen kan alleen worden beantwoord door nieuw opgezet veldwerk, maar een deel kan wel beantwoord worden op grond van nieuwe analyses en bestaande datasets . De belangrijkste uitkomsten van die analyses worden hieronder beschreven.
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