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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    Hier waait de geest van vernieuwing
    Assche, K.A.M. van - \ 2004
    Blauwe Kamer 13 (2004)6. - ISSN 1389-742X - p. 42 - 49.
    industrieterreinen - herstel - stedelijke planning - huisvesting - ontwerp - ? - noord-brabant - woningbouw - cultural heritage - industrial sites - rehabilitation - urban planning - housing - design - house building - noord-brabant
    Het voormalige bedrijfsterrein Strijp S, Eindhoven krijgt een herbestemming tot woon- en cultuurgebied
    Zorgvuldig omgaan met resistentie tegen appelschurft
    Schouten, H.J. - \ 2003
    De Fruitteelt 93 (2003)18. - ISSN 0016-2302 - p. 10 - 11.
    appels - plantenziekteverwekkende schimmels - schurft (bij dieren) - gewasbescherming - ziekteresistentie - epidemiologie - pezizomycotina - steriliseren - venturia inaequalis - apples - plant pathogenic fungi - plant protection - disease resistance - epidemiology - sterilizing - ?
    Appelrassen met schurftresistentie lopen kans deze resistentie te verliezen als verkeerd met deze resistentie wordt omgesprongen. Belangrijke rubrieken in dit artikel zijn: 1) De levenscyclus van schurft op appel; 2) Virulente schurftstammen; 3) Biologische factoren die het proces van onwerkzaam worden van Vf-resistentie vertragen; 4) Ascospoorvorming en geslachtelijke voortplanting; 5) Ontsmetten van Vf-rassen
    Fysioverschillen bij poederschurft in aardappelen niet aangetoond
    Bus, C.B. ; Boerma, M. - \ 2001
    PPO-bulletin akkerbouw 5 (2001)14. - ISSN 1385-5301 - p. 2 - 5.
    spongospora subterranea - plantenziekteverwekkende schimmels - fysiologische rassen - aardappelen - solanum tuberosum - knollen - symptomen - plantenziekten - afwijkingen, planten - cultivars - rassen (planten) - rassenproeven - schimmelziekten - schurft (bij dieren) - veldproeven - fabrieksaardappelen - spongospora subterranea - plant pathogenic fungi - physiological races - potatoes - solanum tuberosum - tubers - symptoms - plant diseases - plant disorders - cultivars - varieties - variety trials - fungal diseases - field tests - ? - starch potatoes
    Vijf aardappelrassen werden twee jaar lang (1998 en 1999) onderzocht op poederschurftaantasting (Spongospora subterranea) op vier verschillende locaties in het zetmeelaardappeltelend gebied in Noordoost-Nederland (Veenkoloniën). Dit om aan te tonen of er fysioverschillen zijn in poederschurftpopulaties tussen proefplaatsen. De gemiddelde aantasting op de knollen per locatie en per ras, en de voorkomende poederschurftsymptomen (verschillend per ras maar niet per locatie), geeft geen aanleiding te veronderstellen dat er fysioverschillen zijn in S. subterranea
    Reflecties op de KNPV Najaarsvergadering over de vraag 'Is biologische teelt beter dan geïntegreerde teelt?'
    Bruggen, A.H.C. van; Termorshuizen, A.J. - \ 2001
    Gewasbescherming 32 (2001)1. - ISSN 0166-6495 - p. 6 - 7.
    biologische landbouw - alternatieve landbouw - duurzaamheid (sustainability) - vergelijkingen - milieubeheer - milieubescherming - ? - alternative farming - farming systems - organic farming - sustainability - comparisons - environmental management - environmental protection
    Discussiepunt op de najaarsvergadering van het KNPV: Biologische landbouw zou milieuvriendelijker zijn dan de gangbare of geïntegreerde landbouw
    Het testen van opgeschaalde Seinhorst-opspoelkannen
    Bekkum, P.J. van; Beers, T.G. van; Beniers, J.E. - \ 2000
    Gewasbescherming 31 (2000)3. - ISSN 0166-6495 - p. 65 - 67.
    aardappelen - dieren - populatiedichtheid - populatie-ecologie - mortaliteit - populatiegroei - ziekteresistentie - plaagresistentie - fysica - meting - methodologie - ? - globodera - potatoes - pratylenchus - heteroderidae - tylenchidae - animals - population density - population ecology - mortality - population growth - disease resistance - pest resistance - physics - globodera
    Om een voldoende grote statistische betrouwbaarheid voor de bepaling van populatiedichtheden van Globodera spp. in wetenschappelijke experimenten of bij het testen van aardappelcultivars ten behoeve van hun partiele resistentie-eigenschappen te verkrijgen, is het nodig om zowel de begin- als de einddichtheid van het aaltje nauwkeurig te bepalen. Twee methoden voor de bepaling van de relative vatbaarheid van aardappelrassen voor aardappelcysteaaltjes worden vergeleken
    The Botrytis cinerea endopolygalacturonase gene family
    Have, A. ten - \ 2000
    Agricultural University. Promotor(en): P.J.G.M. de Wit; J.A.L. van Kan. - S.l. : S.n. - ISBN 9789058082275 - 119
    tomaten - solanum lycopersicum - plantenziekteverwekkende schimmels - botrytis cinerea - polygalacturonase - pectinen - celwanden - degradatie - genetische analyse - genen - tomatoes - solanum lycopersicum - plant pathogenic fungi - botrytis cinerea - pectins - cell walls - degradation - genetic analysis - genes - ?

    C ell w all d egrading e nzyme s (CWDEs) secreted by microbial plant pathogens have been suggested to function as virulence factors. Evidence that particular bacterial CWDEs contribute to virulence has emerged in the last two decades. Targeted gene replacement of different genes encoding CWDEs resulted in mutants with reduced virulence on a number of host plants. Similar molecular genetic approaches in plant pathogenic fungi have, until recently, been unsuccessful in elucidating a role for fungal CWDEs in pathogenesis. This thesis describes molecular genetic analyses of CWDEs secreted by the necrotrophic plant pathogenic fungus Botrytis cinerea , the causal agent of gray mould.

    From literature it was known that B. cinerea secretes many CWDEs when grown in liquid culture. The number of CWDE encoding genes present in the B. cinerea genome was unknown and detailed expression studies were lacking. In order to fill this knowledge gap we used the following strategy:

    1. Cloning of genes encoding CWDEs
    2. Study of the expression of CWDE genes both in liquid cultures and in planta
    3. Targeted deletion of CWDE genes that have expression patterns that indicate a function in the infection process

    Chapter 1 introduces the research area and gives an outline of the thesis. It describes a model of the chemical and structural composition of the plant cell wall and reviews various classes of microbial CWDEs. It summarises previously published data on the role of bacterial and fungal CWDEs in pathogenesis in general and on the CWDEs secreted by B. cinerea in particular. B. cinerea has a wide host range but prefers hosts that contain high amounts of pectin. Therefore the focus was on endo p oly g alacturonases (endoPGs), enzymes that cleave homogalacturonan, a major constituent of pectin.

    In order to study gene expression of B. cinereain planta , it was essential to develop a standardised inoculation procedure that enables reproducible infections both in time and space. The development of this inoculation procedure for tomato leaves is described in Chapter 2. The expression of two fungal genes and a number of plant PR-protein genes was investigated in time course experiments performed at two different incubation temperatures.

    Subsequently, we set out to clone the genes of interest, analysed their expression and studied the effect in pathogenesis by targeted gene replacement. The genes were isolated by hybridisation with heterologous probes. The first gene that was cloned and characterised, Bcpg 1, is constitutively expressed. Targeted replacement of this gene resulted in a mutant with reduced virulence on apple fruits and tomato (Chapter 3). Subsequently, five additional endoPG genes were isolated (Chapter 4). The gene products were compared with other fungal endoPGs and it was shown that the members of the B. cinereaBcpg gene family fall into at least three distinct monophyletic groups (Chapter 4).

    The members of the endoPG gene family, denoted as Bcpg 1-6, are differentially expressed in liquid cultures that differed in carbon source or pH (Chapters 4). The constitutive expression pattern of Bcpg 1, as found in Chapter 3, was further confirmed. Bcpg 2 is expressed under all circumstances tested except when B. cinerea is grown in glucose-containing medium at low pH. Bcpg 3 is expressed at low ambient pH. Bcpg 4 is induced by the pectin breakdown end-product galacturonic acid, and is repressed by glucose. Bcpg 5 expression can be induced by a yet unknown factor present in apple pectin. Bcpg 6 is, like Bcpg 4, induced by galacturonic acid but is, unlike Bcpg 4, not repressed by glucose. The expression of the endoPG gene family enables the fungus to degrade pectate in a flexible manner. It enables the fungus to respond to environmental signals like nutrient availability and pH.

    The expression of the endoPG gene family during infection of tomato leaf, broad bean leaf, apple fruit and courgette fruit was studied (Chapter 5). Expression of the genes in planta is differential and most expression patterns can be explained by the results of expression studies in liquid cultures. Bcpg 1 is expressed in all host tissues tested, whereas expression of Bcpg 2 is evident in tomato, broad bean and courgette. Bcpg 3 and Bcpg 5 are expressed in apple fruit. Bcpg 4 and Bcpg 6 are expressed in all host tissues tested.

    Chapter 6 discusses the results in a broader context. It is hypothesised that, besides Bcpg 1, additional members of the Bcpg gene family contribute to virulence, albeit likely under specific circumstances. It is suggested that fungal CWDEs can play a role in plant pathogenesis but that this role also strongly depends on the lifestyle of the fungus. It is postulated that B. cinerea depends strongly on endoPGs for successful infection. The research described in this thesis may lead to novel disease control strategies that rely on P oly G alacturonase I nhibiting P rotein (PGIP) expression in transgenic host plants.

    The use of the Mesoscale model RAMS to provide local meteorological input for modelling pollutant transport and dispersion over complex terrain
    Vonk, A.W. ; Hofschreuder, P. ; Kroon, L.J.M. - \ 1999
    Wageningen : Wageningen University - 72
    simulatie - modellen - verontreinigende stoffen - dispersie - ? - simulation - models - meteorology - pollutants - dispersion
    Rural Development in Central America : Markets, Livelihoods and Local Governance
    Ruben, R. ; Bastiaensen, J. - \ 1999
    New York : St. Martin's Press - ISBN 9780312226596 - 252
    plattelandsontwikkeling - markten - goederenmarkten - grondmarkten - arbeidsmarkt - landhervorming - centraal-amerika - ? - rural development - markets - commodity markets - land markets - labour market - capital market - land reform - central america
    Rural development is now considered almost synonymous with involvement in market exchange. When market and institutional failures prevail, however, rural communities increasingly rely on local institutional or contractual arrangements to guarantee their livelihoods. This book offers a comprehensive review of the debate on the importance of real markets in the Central American rural development process.
    Proteins regulating cyclin dependent kinases Cdk4 and Cdk5
    Moorthamer, M.J.M.W. - \ 1999
    Agricultural University. Promotor(en): C. Veeger; B. Chaudhuri; J. Visser. - S.l. : S.n. - ISBN 9789058080844 - 101
    kinasen - ? - kinases - protein metabolism

    The exact passage through the eukaryotic cell cycle is regulated by the progressive activation and inactivation of a family Cdk-s. Cancer cells evolve from normal cells when some essential processes in a dividing cell malfunction. This causes inappropriate replication, segregation and repair of the genome during progression of the cell cycle. Increased Cdk4 activity due to overexpression of Cdk4 and/or cyclin D, or because p16 INK4A, the Cdk4 specific inhibitor is missing from the cell, will cause the cell to cycle without a functional restriction point. The duration of the cell cycle shortens giving rise to mistakes in DNA replication. These malignant cells will grow out to form tumours.

    Potential antineoplastic drugs against certain forms of cancer could be synthetic chemicals which would inhibit for instance Cdk4 activity. Screening of compounds on their Cdk inhibitory effect is one example of how pharmaceutical industries are performing cancer research. In chapter 2 of the thesis a method is presented to facilitate Cdk4 compound screening. Human Cdk4 is expressed in the yeast Saccharomyces cerevisiae under the control of the GAL1-GAL10 promoter and inhibits cell growth when the yeast is grown on galactose. Coexpression of p16 INK4Arestores yeast cell growth. Moreover flavopiridol, the Cdk inhibitor which has already entered phase 3 clinical trials, is also restoring growth when it is added to the growth medium of the yeast. Simple OD readings of this yeast transformation when grown on galactose could give useful information upon whether a compound added to the growth medium could be a Cdk4 inhibitor or not. This Cdk4 inhibition will be of certain specificity since the yeast Cdc28 has high homology with human Cdk1 and Cdk2.

    Components, which normally would reside in the cell cycle, have recently been found to function atypically in non-proliferating neuronal cells. The cyclin dependent kinase Cdk5 for instance is identified via its homology with other Cdk-s and has not been shown to play a role in the cell cycle. Cdk5 has a ubiquitous tissue distribution in mammals with brains containing the highest amount of the transcript. On the other hand, the expression of p35, the only known activator of Cdk5, which has no homology to cyclins, is strictly confined to brains. Activated Cdk5 kinase phosphorylates a number of cytoskeletal proteins including neurofilaments and the neuron-specific microtubule associated protein tau in vitro , which are assumed to be the natural substrates. Phosphorylation of cytoskeletal proteins may play an important role in the polymerization and assembly of cytoskeletal elements which, in turn, may effect the growing neurites suggesting that Cdk5 is involved in the growth and maintenance of neurites. Recently Cdk5 has been shown to play a role in differentiation of muscles as well.

    Nerve cells are terminally differentiated before the onset of birth. Since nerves do not have any regeneration capacity, damaged or malignant cells will automatically undergo apoptosis. In the neurodegenerative diseases dementia (diffuse Lewy body disease), Parkinson's and amyotrophic lateral sclerosis neurofilament proteins are hyperphosphorylated whereas in Alzheimer's disease the tau protein is hyperphosphorylated. These malignant nerve cells undergo apoptosis leading to a certain death of the patient suffering from these diseases. Neurodegeneration possibly occurs as a result of inappropriate activation/deactivation of tissue-specific components of the cell cycle. It is very likely that Cdk5 is overactive in these malignant nerve cells.

    Since Cdk5 has been found in both proliferative and differentiated cells it is interesting to search for protein interactions with Cdk5 and the effect of these proteins on the Cdk5 kinase. During these investigations attempts were made to search for protein interactions with Cdk5 in proliferative cells and the possible roles of these proteins towards the Cdk5 kinase.

    In chapter 3 a C-terminal fragment of DNA binding protein, dbpA is described which can bind to Cdk5. This protein-protein interaction is shown via the yeast-two-hybrid system. Several in vitro experiments have confirmed that the C-terminal fragment of dbpA indeed specifically binds to Cdk5. Kinase assays have shown that this protein fragment inhibits the phosphorylation of both histone H1 and pRb by the Cdk5 kinase. DbpA is expressed in skeletal muscle and the heart. Since Cdk5 has been found to play a role in differentiation of muscles it is possible that dbpA plays a role in this phenomenon as well.

    Chapter 4 depicts another Cdk5 binding protein, a 60S ribosomal protein, L34. This protein interaction is discovered via the yeast-two-hybrid system as well. L34 like dbpA blocks the phosphorylation of histone H1 and pRb by Cdk5.

    Cloning of the cdk5 gene has been done via PCR on cDNA libraries. PCR on cDNA from a fetal brain library revealed two PCR products. One of the PCR products had the size of the cdk5 open reading frame whereas the other product was much smaller. Sequencing of both products showed the larger fragment coded indeed for the cdk5 gene whereas the other product was identical with the cdk5 open reading frame with bases 313 to 409 missing in the middle of the gene. In fetal brain this Cdk5 isoform could be expressed which lacks amino acids 105-136, which are thought to be responsible for catalyzing the phosphorylation reaction. Although this Cdk5 isoform (Cdk5i) can bind to p35, little kinase activity has been shown. Since this cdk5 variant has been found in total RNA of SH-SY-5Y neuroblastoma cells as well, but not in cDNA libraries of T-cells, HeLa cells, thymus, placenta and cerebellum, this protein could play a specific role in the differentiation of human nerve cells too. Binding of Cdk5i in these respective cells to p35 could prevent the wildtype Cdk5 from being activated. In this way Cdk5i could modulate the activity of the Cdk5 wildtype kinase. Chapter 5 depicts the results of this research.

    New methods for feasibility studies on establishment of new agricultural production chains
    Meeusen-Van Onna, M.J.G. - \ 1998
    Den Haag : LEI-DLO (Mededeling / Agricultural Economics Research Institute (LEI-DLO) 627) - ISBN 9789052424651 - 48
    landbouwproductie - kettingen - ruwe grondstoffen - verpakkingsmaterialen - economische analyse - methodologie - aanbod - bedrijfsvoering - ? - agricultural production - chains - raw materials - packaging materials - economic analysis - methodology - supply - management
    Coping strategies in dairy cows
    Hopster, H. - \ 1998
    Agricultural University. Promotor(en): P.R. Wiepkema; H.J. Blokhuis. - S.l. : Hopster - ISBN 9789054858423 - 152
    melkvee - melkveehouderij - diergedrag - stress - dierenwelzijn - huisvesting, dieren - karakteristieken - patronen - variatie - myocardium - hartfrequentie - adrenale cortexhormonen - corticosteron - corticotropine - lymfocyten - immuniteit - immunologie - immuunsysteem - ? - dairy cattle - dairy farming - animal behaviour - nervous system - stress - animal welfare - animal housing - characteristics - patterns - variation - myocardium - heart rate - adrenal cortex hormones - corticosterone - corticotropin - lymphocytes - immunity - immunology - immune system

    The central aim of this thesis is to investigate whether individual dairy cows display different and coherent patterns of physiological and behavioural stress responses. Such responses enable them to successful adapt in a changing environment.

    In Chapter 1, current concepts of adaptation and stress are introduced. Adaptation is necessary when the individual's need to perform specific behaviour, does not match the current or anticipated perceptions of the internal or external environment. Such a condition is termed stress . Physical and/or psychological factors that cause, support or magnify such a mismatch are called stressors . The behavioural and physiological responses that compensate this discrepancy are termed stress responses . Adaptation can be measured as the fade out of these responses.

    The degree, in which adaptation is accompanied by stress, is primarily determined by uncertainty, perceived by the organism, when it is not clear how and if adaptive changes can be realized. Individuals may differ remarkably in the way they cope with this problem. In such a situation, broadly speaking, their behaviour ranges between actively avoiding or tackling the problem and passively undergoing it. These two behavioural patterns strongly resemble the classical stress responses, ie fight/flight versus conservation/withdrawal, and are characterized in rodents and man by a specific, integrated pattern of cognitive, emotional, behavioural and physiological responses, termed coping strategies or coping styles .

    The active coping style is characterized by active behavioural responses as well as by dominating sympathetic activity. Increased concentrations of primarily noradrenaline and to a lesser extent adrenalin and glucocorticoid accompany active coping responses. Behavioural inhibition and activation of both the adrenomedullary and the hypothalamus-pituitary-adrenocortical systems is typical of the passive coping style. Passive coping is associated with increased concentration of adrenalin and corticosteroids and to a lesser degree also of noradrenaline.

    Increase in heart rate is suitable for measuring dominating sympathetic activity. Plasma concentrations of cortisol are used for estimating adrenocortical activity. To reliably measure these two parameters in dairy cows, methods were developed for both the recording of heart rate and the 'stress-free' collection of blood samples.

    For heart rate measurements in dairy cows, the Polar® Sport Tester has been modified and validated (Chapter 2). Simultaneous heart rate recordings with both the Polar® and classical ECG-equipment indicated significant correlations between the measurements when cows were quietly standing (0.88) or walking on a treadmill (0.72). Artefacts, caused by muscle contraction, could be easily recognized by their characteristic heart rate patterns. Accordingly, missing values instead of erroneous measurements were produced.

    A method for collecting only a few blood samples from many cows is reported in Chapter 3. Evidence is produced that baseline cortisol concentrations can be measured in single blood samples that are collected by jugular puncture within 1 min of first approaching the cow. To prevent handling from confounding cortisol concentrations, it is necessary that cows are accustomed to handling and to being restrained. When blood samples need to be collected repeatedly, however, jugular puncture may induce an increase in cortisol concentrations which seems to depend on the handling experience of the animal and on individual differences.

    The separation of cow and calf, 2-3 days after calving, evoked only a slight increase in heart rate in cows during the first minute after separation (Chapter 4). During the first 10 min after separation, no other behavioural (activity, vocalisations) or physiological (heart rate, cortisol) signs of stress could be detected. This indicated that the removal of the calf after bonding could not be used for triggering an acute stress response in dairy cows in further experiments.

    In Chapter 5, the preference of dairy cows for visiting a particular side of the milking parlour has been studied in the light of evidence in mice that active coping animals easily develop behavioural routines. Marked differences were found between individual cows in consistency of parlour side choice. Some cows systematically visited one side of the parlour for a longer time, whereas others alternated randomly. Social factors hardly influenced this individual trait. It was surprising, however, that in cows which consistently visited one side of the parlour, deprivation of choice hardly elicited any stress responses (behaviour, heart rate, milk production). Side preference of dairy cows in the milking parlour thus seemed to be a consistent behavioural routine with only unimportant implications for the welfare of cows if it were to be interrupted.

    In Chapter 6, the short- and long-term consistency of behavioural and physiological responses of dairy cows, which were repeatedly tested in a 'novel environment' test, is described. Individual cows showed consistent and individual-specific stress responses. Consistency appeared in behaviour, in heart rate and in plasma cortisol concentrations within one week. Consistency of individual responses was also found for heart rate and plasma cortisol concentrations when tests were spaced 1 yr apart. Handling prior to the exposure to the novel arena, besides the exposure itself appeared to be an important stress-inducing element in the novel environment test. The study produced clear evidence that individual dairy cows differ consistently in the degree to which they respond to environmental challenge, ie a combination of novelty, isolation and handling. The treatment offers exciting opportunities for the objective assessment of an underlying characteristic or psychobiological profile, perhaps fearfulness.

    Ten cows with low and eight cows with high plasma cortisol concentrations in response to the short stay in novel environment, were selected out of the group of 58 heifers. Low- and high responders were labelled LC- and HC-cows respectively. After one year, while in second parity, these cows were separated from herd-mates one after another and isolated and tethered for 55 hr in a stanchion barn (Chapter 7). Intra-mammary administration of E. coli endotoxin produced an acute and transient mastitic episode in all cows with only mild mastitic and systemic reactions. As far as their response to endotoxin is concerned, HC- and LC-cows responded similarly. In response to isolation, however, HC-cows showed stronger stress responses than LC-cows, as indicated by a higher increase in rectal temperature, in cortisol concentration after injection of endotoxin and in the number of vocalisations. Between 8 and 10 h post injection (PI) the number of circulating lymphocytes in HC- but not in LC-cows decreased markedly (40%) to 1.58 x 10 6cells.ml -1and remained so until 21 h PI. These results show that the stress response of dairy cows during social isolation is associated with the number of peripheral blood leukocytes after intra-mammary administration of endotoxin. Because plasma cortisol concentrations hardly differed between HC- and LC-cows, noncorticosteroid factors are likely to be involved.

    In chapter 8, current theories about the control of animal behaviour and the generation of emotional responses will be briefly introduced. These two topics, together with the current concept of adaptation and stress, provide a basis for discussing the findings of this study in an integrated way. The question is addressed why the dichotomy between active and passive coping animals, as reported in rats and mice, is likely to be different in dairy cows. Cumulative effects of domestication, intensive rearing and handling, one-sided selection for milk production and a feminine brain may have weakened the stress response of dairy cows. Therefore, distinct coping styles may be distinguished, although it is likely that such forces have shifted the coping behaviour of dairy cows to a more passive style. Finally the question is addressed how results from this study could contribute to the development of future management practices and breeding strategies.

    Ammonia emission from houses for growing pigs as affected by pen design, indoor climate and behaviour
    Aarnink, A.J.A. - \ 1997
    Agricultural University. Promotor(en): L. Speelman; M.W.A. Verstegen; J.H.M. Metz. - Wageningen : IMAG-DLO - ISBN 9789054856627 - 175
    varkens - kraamstallen - varkensstallen - afmesten - architectuur - ontwerp - layout - grondplannen - diergedrag - ventilatie - luchtverontreiniging - ammoniak - emissie - vervluchtiging - ? - binnenklimaat - pigs - farrowing houses - pig housing - finishing - architecture - design - layout - floor plans - animal behaviour - heating - ventilation - air pollution - ammonia - emission - volatilization - indoor climate

    The ammonia volatilization in pig houses should be reduced to protect the environment and to improve the air quality inside the house. The objective of this study was to examine the effects of various housing factors and animal behaviour on the ammonia volatilization in houses for rearing and fattening pigs. The study was intended to yield ways that pig farmers could reduce the emission of ammonia by combining effective and economic housing measures. A marked increase was found in the ammonia emission during the growing period of the pigs. Ammonia emission was generally higher during the summer than the winter season and was positively related to the urine-fouled floor area and the frequency of urination. Reducing the slatted floor and slurry pit area and using slatted floors of smoother material and with more open space than concrete slatted floors, lowered the ammonia emission. The air quality was improved by using a ventilation system with a low air inlet in the floor of the feeding passage and a low outlet just above the slatted floor, instead of a high diffuse inlet and a high outlet. The ventilation system did not affect the total emission of ammonia. The ammonia emission could be reasonably well predicted with a dynamic numerical model at the low and moderate levels of emission, but was poorly predicted at high levels of emission. It is concluded that by combining simple housing measures it is possible to reduce appreciably ammonia emission from houses for growing pigs at relatively low costs. Furthermore, animal welfare and health and the working conditions of the stockman can be improved by these measures.

    Ph.D. thesis, Institute of Agricultural and Environmental Engineering (IMAG-DLO), department of Livestock Engineering, P.O. Box 43, 6700 AA Wageningen, the Wageningen Institute of Animal Sciences (WIAS) and the Department of Agricultural Engineering and Physics of the Agricultural University Wageningen.

    This study was financially supported by FOMA (Financieringsoverleg Mest- en Ammoniakonderzoek). Their contributions are gratefully acknowledged.

    Waterrecreatie in de Oosterschelde, Voordelta en Waddenzee : een onderzoek onder watersporters in kustwateren naar motieven, gedragingen en bestedingen
    Bruin, A.H. de; Klinkers, P.M.A. - \ 1995
    Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 385) - 144
    vrijetijdsactiviteiten - nederland - recreatie - waterrecreatie - ? - oosterschelde - waddenzee - zuidwest-nederland - voordelta - leisure activities - leisure behaviour - netherlands - recreation - water recreation - eastern scheldt - wadden sea - south-west netherlands - voordelta
    Individual behavioural characteristics in pigs and their consequences for pig husbandry
    Hessing, M.J.C. - \ 1994
    Agricultural University. Promotor(en): P.R. Wiepkema; M.J.M. Tielen; W.G.P. Schouten. - S.l. : Hessing - ISBN 9789054852131 - 135
    varkens - dierenwelzijn - huisvesting, dieren - diergedrag - diergeneeskunde - zenuwstelsel - stress - ? - pigs - animal welfare - animal housing - animal behaviour - pig housing - veterinary science - nervous system - stress
    Introduction
    The main aspect of this thesis is individual behavioural variation. Behavioural variability among individuals within a population may provide information on strategies or roles in social behaviour, on personality traits and individual recognition. Generally, this behavioural variability becomes overt in stressful situations. Recent data have shown the existence of basically two different coping strategies, active or passive. These different coping styles resemble the two (classical) behavioural stress responses, fight-flight vs. conservation-withdrawal, each with its own characteristic biological pattern. The success of the individual coping response depends on the environmental conditions and, therefore, it is highly surprising that each individual appears to be prediposed to one or the other coping strategy. This suggests a genetic or ontogenetic basis, but recent life experiences will have a significant role also. The idiosyncratic response pattern to a challenge has been shown in many species (humans; monkeys; dogs; tree shrews; etcetera), and hence it may be postulated that this also holds for pigs. If so, these individual behavioural characteristics will have important practical implications in understanding the social relations among group-housed pigs in intensive farm conditions. A stable social structure in the group, and thus a proper group composition, may be a function of the individual behavioural characteristics of each group member. However, until now little research has been conducted to reveal possible patterns underlying a proper group composition in pigs, and subsequently how such mechanisms could be applied in intensive pig husbandry. The present study aims at these aspects.

    Social status
    In chapter 1, the individual variation in disease susceptibility and immune reactivity of pigs is described in relation to their individual social status in a stable social group. This social status was determined by the outcome of social ranking fights and food competition tests. There was a substantial agreement between the social status determined by these ranking fights and food competition tests. Since these tests were made at quite different ages (respectively; during the suckling period, and on day 50, on day 65, and on day 100), this indicates a relatively stable social structure in the group. At an age of approximately ten weeks, all pigs were challenged intranasally with an Aujeszky virus. Mortality and morbidity were highest among subordinate pigs compared to subdominant and dominant ones. A specific lymphocyte stimulation test, using purified Apjeszky virus as an antigenic stimulus, showed that the cell-mediated immunity (CMI) against the Aujeszky virus was higher for the dominant pigs than for the subdominant and subordinate ones.

    These findings showed that there were large individual differences in immune reactivity and disease susceptibility in pigs partly related to their individual social status in the group. However, social behaviour of an animal that lives in a social organization is also determined by its individual way of handling stressful situations i.e., its coping strategy. Therefore, the individual coping response may well be another basis for different internal biological programs, which may eventually lead to individual differences in disease susceptibility. In chapter 2 the hypothesis was tested whether consistent individual behavioural characteristics in pigs exist.

    Individual behavioural characteristics
    During the suckling period, piglets were classified as aggressive or as non-aggressive individuals in two successive social confrontation (SC) tests by two observers. Substantial agreement in this classification existed between observers and between both SC tests. Moreover, the aggressive behavioural elements observed after mixing at 10 and again at 15 weeks of age were mainly shown by pigs that were classified as the aggressive ones in the two social confrontation tests shortly after birth; this indicates that the behavioural response pattern of the individuals remained consistent over a long period of time. In a non-social backtest piglets were restrained in a supine position for sixty seconds, and classified as resistant (R;>two escape attempts), intermediate Q; = two escape attempts), or as non-resistant (NR; < two escape attempts). Based upon the outcome of five successive backtests piglets were eventually classified as R (n=95), as NR (n=77), or as Doubtful (n=46). Results showed that two backtests performed on piglets at an early age may suffice for practical use. A striking finding was the good association that existed between the outcome of the backtests and of the SC test. The individuals that resisted in the backtests were the aggressive ones in a social situation, while the non-resistant individuals were the non-aggressive ones. This association and the strong consistency over time strongly suggests an individual behavioural strategy to cope with conflict situations. The idiosyncratic characteristics indicate a bimodal distribution in coping behaviour in pigs; they are active (aggressive and resistant; A/R) or passive (non-aggressive and non-resistant; NA/NR) pigs.

    Individual physiological characteristics
    The way these individual behavioural strategies in pigs relate to different behavioural, physiological, and endocrine responses under stress conditions is illustrated in chapter 3. For this, 32 A/R and 32 NA/NR pigs were selected and individually tested in an open field (OF) test at three and eight weeks of age. While A/R pigs more than NA/NR ones tried to escape the OF, the A/R pigs vocalized less during the OF procedure than the NA/NR ones did. Furthermore, the A/R ones explored a novel object inside the OF rapidly and superficially, whereas the NA/NR ones did so gradually but more intensively. The cortisol response to the OF (t=0/t=90) differed between the A/R and the NA/NR pigs. The cortisol response to a farmacological dosis ACTH 1-39 (2.5 IU/kg live weight/pig) at three and eight weeks of age showed no significant differences between both types of pigs. Nonetheless, the basal cortisol levels were consistently higher for NA/NR pigs than for A/R ones, and this was eventually accompanied by adrenal hypertrophy in the former. The mean heart rate (HR) in beats/min (bpm) was higher of the A/R pigs compared to the NA/NR ones in two backtests. Moreover, in reaction to the novel object (a falling bucket) in the (second) OF HR of the A/R pigs substantially increased (23.9 bpm = 15.5%), while HR of the NA/NR pigs only slightly increased (4.5 bpm = 2.9%). Surprisingly, one-third of the NA/NR individuals even showed a HR decrease (bradycardia) in response to the falling bucket. This implies that the active pigs (A/R) reacted predominantly with a sympathetic response, and the passive pigs (NA/NR) with a parasympathetic one; these findings strongly parallel data found in other animals and humans. The sympathetic response of the active pigs resulted in heart deviations. Thus, active and passive pigs displayed consistent individual differences in behavioural, physiological, and endocrine responses to stress situations leading to different stress pathologies.

    Individual immunological characteristics
    Chapter 4 reports about individual differences in cell-mediated and humoral immunity as related to different coping styles in pigs. The immune reactivity of 32 A/R and 32 NA/NR pigs was tested in relation to stress using several cell-mediated (CMI) and humoral immunological tests. Results indicated that the active pigs had a higher in vivo and in vitro CMI to non-specific and specific antigens than the passive pigs. Furthermore, in reaction to stressors applied in the present study (i.e., weaning, new environment, transportation, mixing) active pigs had a reduced but temporary CMI response in the first phase of stress, while passive pigs showed a more chronic impairment. In contrast, the passive pigs displayed higher levels of specific antibodies than the active ones. This suggests a converse relationship in the individual pig between CMI and humoral immunity, in that active pigs had a high CMI but a low humoral immunity, whereas passive pigs had a low CMI but a high humoral immunity. This converse relationship may be associated with different levels of glucocorticoids as described in chapter 3. In conclusion, active and passive pigs clearly differed in their immune reactivity to stressful situations.

    Practical implications
    How far group composition based on the individual coping characteristics may influence the growing up of fattening pigs was tested at a commercial closed farm (cf. chapter 5). During the suckling period, piglets of this farm were individually tested in two successive backtests, and classified as R, NR, or as D. At nine weeks of age, the pigs were grouped into six pens with only R pigs (R pens), six pens with only NR pigs (NR pens), and six pens with both R and NR ones (R/NR pens). The average daily weight gain (ADWG; grams/day) was highest of the pigs in the R/NR pens compared to the pigs in the R pens and in the NR pens. Moreover, the coefficient of variation of A~ was lower among R/NR pens than among R pens or NR pens. The carcass weight and meat% was somewhat higher and carcass classification was better of the pigs in the R/NR pens than the pigs in the R pens and in the NR pens. Additionally, pigs in the R/NR pens had less pleurisy than the pigs in the other pens, whereas the number of pigs with stomach wall damage was highest for pigs in the NR pens. Groups consisting of both active (R pigs) and passive (NR pigs) individuals seem to better fit each other than groups with only active or with only passive ones and, thus it is worthwhile to compose groups of pigs based on their individual behavioural characteristics. In practice, good management implies besides perfect climatic and feeding conditions also attention for and understanding of the social environment of the farm animals.

    General Discussion
    In the general discussion three major topics are discussed: 1) do the behavioural differences in pigs represent idiosyncratic response patterns; 2) do the individual behavioural characteristics in pigs relate to different autonomic nervous and immune reactivity under stress conditions and 3) the relevance of applying behavioural studies in pigs in practice. Especially the intriguing finding that under stressful conditions active and passive pigs need each other to develop a stable social organization needs further research.

    Geur- en ammoniakemissie tijdens het indampen van mest bij de HEPAQ - milieustal
    Hoeksma, P. ; Berg, A.J. van den - \ 1993
    Wageningen : IMAG-DLO (Rapport / Instituut voor Mechanisatie, Arbeid en Gebouwen 93-35) - 27
    luchtverontreiniging - ammoniak - rundveedrijfmest - emissie - evaporatie - schadelijke dampen - gezondheidsbescherming - vloeibare meststoffen - mest - varkensstallen - vervluchtiging - ? - mestoverschotten - mestverwerking - air pollution - ammonia - cattle slurry - emission - evaporation - fumes - health protection - liquid manures - manures - odours - pig housing - volatilization - manure surpluses - manure treatment
    Het gebruik van een selectiepoort voor automatisch melken : de invloed op het gedrag en het welzijn van koeien = The use of a selection unit for automatic milking : the influence on the behaviour and welfare of dairy cows
    Ketelaar - de Lauwere, C.C. - \ 1992
    Wageningen : IMAG-DLO (Rapport / Instituut voor Mechanisatie, Arbeid en Gebouwen 92-4) - ISBN 9789054060215 - 34
    huisvesting, dieren - dierenwelzijn - automatisering - melkvee - melkveehouderij - machinaal melken - verwerking - productie - robots - ? - animal behaviour - animal housing - animal welfare - automation - dairy cattle - dairy farming - machine milking - processing - production - robots
    Recreatie in het Nationaal Park Dwingelderveld
    Visschedijk, P.A.M. - \ 1990
    Wageningen : "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer (Rapport / "De Dorschkamp" Instituut voor Bosbouw en Groenbeheer nr. 582) - 92
    openluchtrecreatie - recreatie op het platteland - recreatie - onderzoek - budgetten - recreatieonderzoek - vrijetijdsactiviteiten - vrijetijdsgedrag - nationale parken - nederland - ? - drenthe - outdoor recreation - rural recreation - recreation - research - budgets - leisure research - leisure activities - leisure behaviour - nature reserves - national parks - netherlands - drenthe
    Ontwikkeling van abnormaal gedrag bij vleeskalveren in groepshuisvesting : effecten van ruwvoerverstrekking = Development of abnormal behaviour in group-housed veal calves : effects of roughage supply
    Kooijman, J. ; Wierenga, H.K. ; Wiepkema, P.R. - \ 1990
    Zeist : IVO "Schoonoord" (Rapport / IVO "Schoonoord" B-356) - 48
    huisvesting, dieren - dierenwelzijn - kalveren - voedingsrantsoenen - vleesproductie - ruwvoer (roughage) - ? - animal behaviour - animal housing - animal welfare - calves - feed rations - meat production - roughage
    Het voeren van kunstmelk met een drijfspeen en het verstrekken van water via een drinknippel aan vleeskalveren in groepshuisvesting : effecten op gedrag en produktie = Feeding milk replacer with a floating rubber teat and supplying water via a nipple to group-housed veal calves
    Wee, E. ter; Wierenga, H.K. ; Jorna, I.P. - \ 1989
    Zeist : IVO (Rapport / Instituut voor Veeteeltkundig Onderzoek "Schoonoord" B-329) - 49
    huisvesting, dieren - dierenwelzijn - drinkbakken, schaalvormig - kalveren - drinkbakken - vleesproductie - pompen - ? - animal behaviour - animal housing - animal welfare - bowl drinkers - calves - drinkers - meat production - pumps
    Vleeskalveren in groepshuisvesting kunnen gaan urinedrinken door een onbevredigde zuigbehoefte. Als bij het urinedrinken grote hoeveelheden urine worden opgenomen, dan kan dit tot gevolg hebben dat de urinedrinkers in groei achterblijven. Daarom is in het uitgevoerde onderzoek gekeken naar invloed van het voeren van melk met drijfspeen en waterverstrekking met drinknippel op het urinezuiggedrag. Tevens is de invloed op de produktie in beschouwing genomen. Hiervan bleek uiteindelijk geen positief effect waar te nemen
    The development and causation of feather pecking in the domestic fowl
    Blokhuis, H.J. - \ 1989
    Agricultural University. Promotor(en): P.R. Wiepkema. - S.l. : Blokhuis - 109
    pluimvee - kippen - diergedrag - huisvesting, dieren - veren (vogel) - ? - poultry - fowls - animal behaviour - animal welfare - animal housing - feathers

    Feather pecking in poultry consists of pecking directed at the feathers of other birds, sometimes pulling out and eating these feathers. It may result in severe damage of the integument of the birds, including wounds of the skin. Finally wounded birds may be pecked to death (cannibalism). About 30 years ago, when most poultry was kept in traditional floor systems, this behaviour was an important cause of mortality. Nowadays most birds are housed in small groups in battery cages in modern poultry houses and in The Netherlands they are usually beaktrimmed (partial amputation of the beak). This resulted somehow in a decreased mortality due to feather pecking.

    However, the effects of feather pecking may have become less fatal, the behaviour as such did not decrease and pecking still causes a lot of (feather) damage and feather pecking is still a problem in modern poultry farming.

    Firstly, the problem relates to animal welfare, which is clearly at stake for the pecked birds. Moreover, beaktrimming may counteract the occurrence of cannibalism and may prevent a lot of suffering, it is a painful operation which should be omitted if possible.

    Secondly, feather pecking is also economically detremental. Defeathering has a pronounced increasing effect on heat production, leading to an estimated increase of energetic needs between 5 and 20 % for laying hens in battery cages.

    The development and expected practical use of alternative systems for laying hens is also relevant with respect to feather pecking. As these systems often incorporate characteristics of traditional floor systems, this may enhance feather pecking.

    The present study was aimed at elucidating the basic motivation behind feather pecking and the process leading to it.

    In Chapter 2 pecking behaviour of birds on a litter floor was compared with that of birds on a slatted floor, from hatching until 17 weeks of age. The average frequency (per animal per hour) of pecking at conspecifics was 73.2 in groups on slatted floors and 27.8 in groups on litter. It increased over time in groups on slatted floors, whereas it tended to decrease in groups on litter floors. Moreover, in the latter pecking at conspecifics was much less damaging. Here about 20 % of the pecks was directed at particles on the plumage of other birds, which is relatively harmless, and about 25 % at feathers. In the groups without litter, these percentages were 1 and 55 respectively.

    Ground pecking frequency appeared to be about 6 times higher in groups on litter compared to groups on a slatted floor.

    At 17 weeks of age the experiment was continued by transferring half of the animals from each floor-type to the other type of flooring material. Most striking was that animals reared on litter and changed to slats, showed a strong increase of pecking at conspecifics (together with an increase in feather damage) and a strong decrease of ground pecking. Birds reared on slats and moved to litter showed a strong increase in ground pecking and the majority showed a decrease of pecking at conspecifics. In the latter birds, plumage recovered from the damage done to it in the first part of the experiment.

    It was concluded that the results supported the hypothesis that feather pecking evolves as redirected ground pecking.

    Experimental evidence to support this hypothesis is presented in Chapters 3 and 4. In Chapter 3 the motivation for groundpecking was experimentally varied in 6 week old female chicks, housed on litter. The same experimental procedure that stimulated ground pecking in chicks on a litter floor, appeared to stimulate feather pecking in chicks on a slatted floor. This supports the hypothesis that ground pecking and feather pecking share common causal factors. Chapter 4 takes another approach to test the same hypothesis. Here, again using 6 week old chicks, floor-type was suddenly changed from a half litter half slatted floor into a full slatted floor. The fact that groundpecking decreased and feather pecking increased again supported the above hypothesis.

    The redirection of ground pecking was described in both chapters in terms of incentive motivation theory. In this concept of motivation the role of incentive stimuli in inducing motivational states and in directing behaviour is emphasized. Specific characteristics of litter, a slatted floor or feathers which may affect their ranking as an incentive are discussed. Possibly visual, tactile or gustatory feedback signals play a role, as well as positive long-term effects of ingestion. Moreover, it was stated that the possibility to perform specific consummatory behaviour patterns, may also affect the validation of a substrate as an incentive. In relation to this it was also suggested that the possibility to perform groundscratching in combination with pecking, may add to the stimulus feedback. Obviously the animal's past experience with environmental stimuli is crucial in the validation of stimuli as incentive.

    In Chapter 5 the effects of early experience with litter were studied. Hens were reared on litter floors (20 groups) or on wire floors (20 groups) until 17 weeks of age. Then all groups were moved to pens with half litter half slatted floors. It appeared that feather pecking was less in litter reared hens compared to hens reared on wire. Also feather damage was less in the litter reared groups. It was concluded that experiences during rearing influence pecking preferences during the laying period.

    In the same experiment the effect of beaktrimming was studied. As the beak of the chicken has a variety of sensory receptors, beaktrimming is likely to result in sensory deficits. This may affect tactile discrimination and interfere with the validation of an object as an incentive for pecking. During the rearing period beaktrimmed birds showed a lower frequency of ground pecking as well as feather pecking, on litter as well as wire floors. During the laying period all groups showed the same level of ground pecking irrespective of beaktrimming or floor type. Beaktrimming only showed an effect on feather pecking in the wire reared groups. Here feather pecking reached a very high level, although it did not much harm to the plumage of the birds. It was concluded that beak trimming does not change pecking preference nor does it decrease pecking frequency. Beaktrimming is effective in reducing feather pecking damage.

    In Chapter 6, it is reported that a high housing density significantly decreases ground pecking and scratching in young domestic fowl. Although no serious feather pecking occurred, it is suggested that a high housing density stimulates the redirection of ground pecking which may result in the development of feather pecking.

    In the general discussion (Chapter 7) a regulatory model of ground pecking is presented, in which the role of incentives is incorporated. The motivation of pecking is discussed and it is concluded that pecking serves several functions such as energy supply, consummatory stimulation or information gathering. The model of ground pecking is modified to allow the incorporation of these different functions. On the basis of this model some suggestions for future research are made. In a last paragraph the risk of some husbandry factors in relation to the occurrence of feather pecking are discussed and some measures to prevent feather pecking are suggested.

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