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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    Effects of climate change and adaptation on the livestock component of mixed farming systems : A modelling study from semi-arid Zimbabwe
    Descheemaeker, Katrien ; Zijlstra, Mink ; Masikati, Patricia ; Crespo, Olivier ; Homann-Kee Tui, Sabine - \ 2018
    Agricultural Systems 159 (2018). - ISSN 0308-521X - p. 282 - 295.
    Crop-livestock interactions - Crude protein - Forage - Metabolizable energy - Resilience - Soil fertility - Vulnerability

    Large uncertainties about the impacts of climate change and adaptation options on the livestock component of heterogeneous African farming systems hamper tailored decision making towards climate-smart agriculture. This study addressed this knowledge gap through the development and use of a dynamic modelling framework integrating climate, crop, pasture and livestock models. The framework was applied to a population of 91 farms located in semi-arid Zimbabwe to assess effects on livestock production resulting from climate change and management interventions. Climate scenarios representing relative "cool-wet", "hot-dry" and "middle" conditions by mid-century (2040-2070) for two representative concentration pathways were compared with the baseline climate. On-farm fodder resources and rangeland grass production were simulated with the crop model APSIM and the pasture model GRASP respectively. The simulated fodder availability was used in the livestock model LIVSIM to generate various production indicators including milk, offtake, mortality, manure, and net revenue. We investigated the effects of two adaptation packages targeting soil fertility management and crop diversification and quantified the sensitivity to climate change of both current and improved systems. Livestock productivity was constrained by dry-season feed gaps, which were particularly severe for crude protein and caused by the reliance on rangeland grazing and crop residues, both of low quality in the dry season. Effects on grass and stover production depended on the climate scenario and the crop, but year-to-year variation generally increased. Relative changes in livestock net revenue compared to the baseline climate varied from a 6% increase to a 43% decrease, and the proportion of farmers negatively affected varied from 20% to 100%, depending on the climate scenario. Adverse effects of climate change on average livestock production usually coincided with increased year-to-year variability and risk. Farms with larger stocking density faced more severe feed gaps and were more sensitive to climate change than less densely stocked farms. The first adaptation package resulted in increased stover production and a small increase in livestock productivity. The inclusion of grain and forage legumes with the second package increased milk productivity and net revenues more profoundly by 30%. This was attributed to the alleviation of dry-season feed gaps, which also reduced the sensitivity to climate change compared to the current system. Clearly, individual farms were affected differently by climate change and by improved farm management, illustrating that disaggregated impact assessments are needed to effectively inform decision making towards climate change adaptation.

    Scientific opinion: Risks for animal health related to the presence of zearalenone and its modified forms in feed
    Knutsen, Helle-Katrine ; Alexander, Jan ; Barregård, Lars ; Bignami, Margherita ; Brüschweiler, Beat ; Ceccatelli, Sandra ; Cottrill, Bruce ; Dinovi, Michael ; Edler, Lutz ; Grasl-Kraupp, Bettina ; Hogstrand, Christer ; Hoogenboom, L.A.P. ; Nebbia, Carlo Stefano ; Petersen, Annette ; Rose, Martin ; Roudot, Alain-Caude ; Schwerdtle, Tanja ; Vleminckx, Christiane ; Vollmer, Günter ; Wallace, Heather ; Dall'asta, Chiara ; Dänicke, Sven ; Eriksen, Gunnar-Sundstøl ; Altieri, Andrea ; Roldán-Torres, Ruth ; Oswald, Isabelle P. - \ 2017
    EFSA Journal 15 (2017)7. - ISSN 1831-4732
    Zearalenone (ZEN), a mycotoxin primarily produced by Fusarium fungi, occurs predominantly in cereal grains. The European Commission asked EFSA for a scientific opinion on the risk to animal health related to ZEN and its modified forms in feed. Modified forms of ZEN occurring in feed include phase I metabolites α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), zearalanone (ZAN) and phase II conjugates. ZEN has oestrogenic activity and the oestrogenic activity of the modified forms of ZEN differs considerably. For ZEN, the EFSA Panel on Contaminants in the Food Chain (CONTAM) established no observed adverse effect levels (NOAELs) for pig (piglets and gilts), poultry (chicken and fattening turkeys), sheep and fish (extrapolated from carp) and lowest observed effect level (LOAEL) for dogs. No reference points could be established for cattle, ducks, goats, horses, rabbits, mink and cats. For modified forms, no reference points could be established for any animal species and relative potency factors previously established from rodents by the CONTAM Panel in 2016 were used. The dietary exposure was estimated on 17,706 analytical results with high proportions of left-censored data (ZEN about 60%, ZAN about 70%, others close to 100%). Samples for ZEN were collected between 2001 and 2015 in 25 different European countries, whereas samples for the modified forms were collected mostly between 2013 and 2015 from three Member States. Based on exposure estimates, the risk of adverse health effects of feed containing ZEN was considered extremely low for poultry and low for sheep, dog, pig and fish. The same conclusions also apply to the sum of ZEN and its modified forms.
    High-resolution phylogeny providing insights towards the epidemiology, zoonotic aspects and taxonomy of sapoviruses
    Barry, A.F. ; Durães-Carvalho, R. ; Oliveira-Filho, Edmilson F. ; Alfieri, A. ; Poel, W.H.M. Van der - \ 2017
    Infection, Genetics and Evolution 56 (2017). - ISSN 1567-1348 - p. 8 - 13.
    Epidemiology - Phylogeny - Sapoviruses - Taxonomy - Zoonoses
    The evolution, epidemiology and zoonotic aspects of Sapoviruses (SaV) are still not well explored. In this study, we applied high-resolution phylogeny to investigate the epidemiological and zoonotic origins as well as taxonomic classification of animal and human SaV. Bayesian framework analyses showed an increase in porcine SaV (PoSaV) population dynamics and genetic diversity between 1975 and 1982, resulting in a SaV gene flow and generation of new strains among porcine and human populations. Our results also show the contribution of different animal populations involved in SaV epidemiology and highlight zoonotic aspects, as exemplified by the crucial role that swine, dogs, mink and humans play in SaV spread. Additionally, phylogenetic analysis suggests that bats may play key role in SaV epidemiology. According to our hypothesis, these animals may act as reservoirs or intermediate host species, contributing to viral spread in zoonotic and other epidemiological scenarios and facilitating the generation of new SaV genogroups and genotypes through recombination events. Data from large-scale phylogeny partition based on patristic distance, did not show a correlation between transmission clusters on generation of SaV genogroups, nevertheless we present both important findings about SaV taxonomy and important considerations useful for further taxonomical studies.
    AgMIP 6, Seeking Sustainable Solutions
    Zijlstra, Mink - \ 2016
    Impact of climate change on the livestock component of mixed farming systems: modeling evidence from regional integrated assessments across sub-Saharan Africa and South Asia
    Estimation of indirect genetic effects in group-housed mink (Neovison vison) should account for systematic interactions either due to kin or sex
    Alemu, S.W. ; Berg, P. ; Janss, L. ; Bijma, P. - \ 2016
    Journal of Animal Breeding and Genetics 133 (2016)1. - ISSN 0931-2668 - p. 43 - 50.
    Social interactions among individuals are abundant, both in wild and in domestic populations. With social interactions, the genes of an individual may affect the trait values of other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models. Most IGE models assume that individuals interact equally to all group mates irrespective of relatedness. Kin selection theory, however, predicts that an individual will interact differently with family members versus non-family members. Here, we investigate kin- and sex-specific non-genetic social interactions in group-housed mink. Furthermore, we investigated whether systematic non-genetic interactions between kin or individuals of the same sex influence the estimates of genetic parameters. As a second objective, we clarify the relationship between estimates of the traditional IGE model and a family-based IGE model proposed in a previous study. Our results indicate that male siblings in mink show different non-genetic interactions than female siblings in mink and that this may impact the estimation of genetic parameters. Moreover, we have shown how estimates from a family-based IGE model can be translated to the ordinary direct–indirect model and vice versa. We find no evidence for genetic differences in interactions among related versus unrelated mink.
    Informatiedocument leefoppervlakte : relatie tussen welzijns- en milieuregelgeving
    Ellen, H.H. ; Buisonje, F.E. de - \ 2015
    Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 849) - 27
    dierenwelzijn - dierlijke productie - rundvee - schapen - geiten - varkens - pluimvee - nerts - konijnen - huisvesting, dieren - milieu - wetgeving - biologische landbouw - milieuwetgeving - emissie - bodemoppervlak - animal welfare - animal production - cattle - sheep - goats - pigs - poultry - mink - rabbits - animal housing - environment - legislation - organic farming - environmental legislation - emission - floor area
    Er is een nauwe relatie tussen het leefoppervlak per dier en de emissie van ammoniak. Over het algemeen geeft meer oppervlak een hogere emissie. Vanuit welzijnsregelgeving zijn veelal minimale oppervlaktes voorgeschreven. In de stalbeschrijvingen van de Rav worden ook eisen gesteld aan de oppervlakte per dier. In dit rapport worden voor de diverse diercategorieën de eisen voor leefoppervlakte vanuit de welzijnsregelgeving vergeleken met die in de stalbeschrijvingen. Een belangrijk aspect is daarbij de definitie van het begrip leefoppervlakte.
    Indirect genetic effects for group-housed animals
    Alemu, S.W. - \ 2015
    Wageningen University. Promotor(en): Johan van Arendonk, co-promotor(en): L.G. Janss; Piter Bijma; P. Berg. - Wageningen : Wageningen University - ISBN 9788793176713 - 228
    nerts - pluimvee - groepshuisvesting - genetische effecten - sociaal gedrag - agressief gedrag - interacties - heritability - veredelingsprogramma's - statistische analyse - genetische parameters - selectief fokken - mink - poultry - group housing - genetic effects - social behaviour - aggressive behaviour - interactions - heritability - breeding programmes - statistical analysis - genetic parameters - selective breeding

    ABSTRACT

    Alemu, SW(2015) Indirect Genetic effects for Group-housed Animals. Joint PhD thesis between Aarhus University, Denmark and Wageningen University, the Netherlands.

    Social interactions among individuals are common both in plants and animals. With social interactions, the trait value of an individual may be influenced by the genes of its interacting partners, a phenomenon known as indirect genetic effects (IGE). An IGE is heritable effect of an individual on trait values of another individual. A large body of literature has shown that social interactions can create addition heritable variation in both plants and animals, for both behavioural and production traits.

    When IGE are estimated it is usually assumed that an individual interacts equally with all its group mates, irrespective of genetic relatedness. This assumption may not be true in mixed groups of kin and non-kin, where an individual may interact systematically different with kin and non-kin. Current IGE models ignore such systematically different interactions between kin and non-kin. Thus, the main aim of this thesis was to develop and apply statistical methods to estimate IGE when interactions differ between kin and non-kin.

    Social interactions are important in mink that are kept in groups for the production of fur. Group housing of mink increases aggression behaviours, which is reflected by an increase in the number of bite marks on the pelts, and reduces the welfare of the animals. We estimated the genetic parameter for bite mark traits in group-housed mink, to investigate the prospects for genetic improvement of bite mark traits. We found that there are good prospects to produce mink that have a low level of biting. Finally, we further concluded that genetic parameter estimation for bite mark score should take into account systematic interactions due to sex or kin.

    In this thesis we also investigated genomic selection for socially affected traits, considering survival time in two lines of brown egg layers showing cannibalistic behaviour. Despite the limited reference population of ~234 progeny tested sires, the accuracy of estimated breeding values (EBV) was ~35% higher for genomic selection compared with the parent average-EBV. We found that the response to genomic selection per year for line B1 was substantially higher than for the traditional breeding scheme, whereas for line BD response was slightly higher than for the traditional breeding scheme. In conclusion, genetic selection with IGE combined with marker information can substantially reduce detrimental social behaviours such as cannibalism in layers and biting in group-housed mink.

    The status of the American mink (Neovison vison) in the Netherlands
    Dekker, J.J.A. ; Hofmeester, T.R. - \ 2014
    Lutra 57 (2014)1. - ISSN 0024-7634 - p. 5 - 15.
    fauna - martes - nerts - wilde dieren - populatie-ecologie - nederland - fauna - martes - mink - wild animals - population ecology - netherlands
    The American mink (Neovison vison) is a north American mustelid that has been farmed for its fur in Europe since the 1920s. It has been feral in the Netherlands since 1958. This paper discusses its distribution, diet, the indications for reproduction, and whether feral animals are born in the wild or are escapees. The American mink mostly occurs in areas where many mink are kept in farms. The largest distance between an observation and the nearest farm was 45 km. Sixteen animals caught by muskrat control officers were dissected. The stomach content of the 16 animals revealed a diet of amphibians, birds and small mammals. The dissections gave no clues about reproduction: one of three males was sexually active, but none of the 13 females showed placental scars, a thickened uterus or signs of lactation. Only one observation of reproduction in the wild was received. Isotope analyses of teeth and nails indicate that the animals generally only stay feral for a short period of time before being caught. The ratios of carbon and nitrogen isotopes of the wild caught animals were very close to the isotope ratios of ten reference animals from a fur farm, except for one adult female, whose teeth isotope values were different from the farm animals and as such she seems to have remained in the wild for longer and was possibly born in the wild. In general however most animals are caught shortly after escaping and only remain in the wild for a short period of time. It seems that feral mink stem from constant escapes and that muskrat control removes these feral animals. Thus, the existence or development of a feral population in the Netherlands is unlikely, especially since it is planned to phase out mink farming by 2024.
    Size distribution of airborne particles in animal houses
    Lai, T.L.H. ; Aarnink, A.J.A. ; Cambra-López, M. ; Huynh, T.T.T. ; Parmentier, H.K. ; Groot Koerkamp, P.W.G. - \ 2014
    Agricultural Engineering International 16 (2014)3. - ISSN 1682-1130 - p. 28 - 42.
    The concentration and size distribution of airborne particles were measured inside and outside typical animal houses such as broilers, broiler breeders (both floor housing with litter); layers (floor housing system and aviary housing system); turkeys (floor housing with litter), pigs: fattening pigs (traditional houses, low emission houses with dry feed, and low emission houses with wet feed), piglets, sows (individual and group housing); cattle (cubicle house), and mink (cages). Using an aerosol spectrometer, particles were counted and classified into 30 size classes (total range: 0.25 – 32 µm). Particles were measured on for two days, one in spring and the other in summer, in two of each species/housing combination during 30 min inside and outside the animal house. Outside temperature and relative humidity were also measured. Particle counts in the different size classes were generally higher in poultry houses than in pig houses, and counts in pig houses were generally higher than those in cattle and mink houses. The particle counts in animal houses were highest (on average 87%) in the size classes 2.5 µm (on average 97%). Most particles outside were in the size class
    Indirect genetic effects contribute substantially to heritable variation in aggression-related traits in group-housed mink (Neovison vison)
    Alemu, S.W. ; Bijma, P. ; Moller, S. ; Janss, L. ; Berg, P. - \ 2014
    Genetics, Selection, Evolution 46 (2014). - ISSN 0999-193X - 11 p.
    group selection - variance-components - biological groups - mustela-vison - multilevel selection - social interactions - competition - parameters - model - populations
    Background Since the recommendations on group housing of mink (Neovison vison) were adopted by the Council of Europe in 1999, it has become common in mink production in Europe. Group housing is advantageous from a production perspective, but can lead to aggression between animals and thus raises a welfare issue. Bite marks on the animals are an indicator of this aggressive behaviour and thus selection against frequency of bite marks should reduce aggression and improve animal welfare. Bite marks on one individual reflect the aggression of its group members, which means that the number of bite marks carried by one individual depends on the behaviour of other individuals and that it may have a genetic basis. Thus, for a successful breeding strategy it could be crucial to consider both direct (DGE) and indirect (IGE) genetic effects on this trait. However, to date no study has investigated the genetic basis of bite marks in mink. Result and discussion A model that included DGE and IGE fitted the data significantly better than a model with DGE only, and IGE contributed a substantial proportion of the heritable variation available for response to selection. In the model with IGE, the total heritable variation expressed as the proportion of phenotypic variance (T2) was six times greater than classical heritability (h2). For instance, for total bite marks, T2 was equal to 0.61, while h2 was equal to 0.10. The genetic correlation between direct and indirect effects ranged from 0.55 for neck bite marks to 0.99 for tail bite marks. This positive correlation suggests that mink have a tendency to fight in a reciprocal way (giving and receiving bites) and thus, a genotype that confers a tendency to bite other individuals can also cause its bearer to receive more bites. Conclusion Both direct and indirect genetic effects contribute to variation in number of bite marks in group-housed mink. Thus, a genetic selection design that includes both direct genetic and indirect genetic effects could reduce the frequency of bite marks and probably aggression behaviour in group-housed mink.
    Co-existence of Distinct Prion Types Enables Conformational Evolution of Human PrPSc by Competitive Selection
    Haldiman, T. ; Kim, C. ; Cohen, Y. ; Chen, W. ; Blevins, J. ; Qing, L. ; Cohen, M.L. ; Langeveld, J.P.M. ; Telling, G.C. ; Kong, Q. ; Safar, J.G. - \ 2013
    Journal of Biological Chemistry 288 (2013). - ISSN 0021-9258 - p. 29846 - 29861.
    creutzfeldt-jakob-disease - transmissible mink encephalopathy - chronic wasting disease - dependent immunoassay - strain variation - transgenic mice - molecular-basis - protein - scrapie - classification
    The unique phenotypic characteristics of mammalian prions are thought to be encoded in the conformation of pathogenic prion proteins (PrPSc). The molecular mechanism responsible for the adaptation, mutation, and evolution of prions observed in cloned cells and upon crossing the species barrier remains unsolved. Using biophysical techniques and conformation-dependent immunoassays in tandem, we isolated two distinct populations of PrPSc particles with different conformational stabilities and aggregate sizes, which frequently co-exist in the most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD). The protein misfolding cyclic amplification (PMCA) replicates each of the PrPSc particle types independently, and leads to the competitive selection of those with lower initial conformational stability. In serial propagation with a nonglycosylated mutant PrPC substrate, the dominant PrPSc conformers are subject to further evolution by natural selection of the subpopulation with the highest replication rate due to its lowest stability. Cumulatively, the data show that sCJD PrPSc is not a single conformational entity, but a dynamic collection of two distinct populations of particles. This implies the co-existence of different prions, whose adaptation and evolution are governed by the selection of progressively less stable, faster replicating PrPSc conformers.
    Methoden voor euthanasie op het primaire bedrijf en standaardwerkwijzen voor het doden van nertsen = Methods for on-farm euthanasia and standard operation procedures for killing of mink
    Lambooij, E. ; Hindle, V.A. - \ 2013
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 683) - 20
    pelsdierhouderij - nerts - euthanasie - doden van dieren - dierenwelzijn - efficiëntie - fur farming - mink - euthanasia - killing of animals - animal welfare - efficiency
    A literature survey reveals several authorized methods of euthanasia. These methods were evaluated on criteria as animal welfare, effectiveness, efficiency and aesthetics of operation. Standard operation procedures for mink were drawn up.
    Effects of air quality on chicken health
    Lai, T.L.H. - \ 2012
    Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Henk Parmentier; Andre Aarnink. - S.l. : s.n. - ISBN 9789461732453 - 177
    pluimvee - huisvesting van kippen - diergezondheid - luchtkwaliteit - vleeskuikens - infectie door luchtdeeltjes - poultry - chicken housing - animal health - air quality - broilers - airborne infection

    Houses for intensive poultry production likely contain very high concentrations of airborne contaminants that may negatively affect human and animal health. However, very little is known of the relations between concentrations, size, nature and composition of airborne particles on animal health in intensive livestock housing. Also, mechanisms of responses of animals to unhygienic conditions such as airborne particles, and adaptation responses are unknown. It is likely that animals under high pressure for production such as broiler chickens may be affected severely by continuous antigenic stimulation. Accordingly, the aim of this thesis was to determine effects of airborne dust and its components, and particle size, respectively on the immune system of broilers, and consequently disease resistance and performance (in this case growth). The objectives were to address 1) dust concentrations and particle size distribution present in counts and in mass inside (and around) animal houses; 2) whether dust or its components (with emphasis on pathogen associated molecular patterns or PAMP) affect the immune competence and specific immune response of broilers after challenge via the respiratory tract at different ages; 3) whether broilers may adapt to respiratory challenge with dust and its different components, and particle size; 4) whether dust and its components including particle size affect growth (and heart parameters) of broilers; and finally 5) localization of 1 µm and 10 µm (fluorescent-labelled polystyrene) particles as a model for localization and transport of dust particles in the body of broilers after challenge via the respiratory route

    In terms of mass, the dust concentration in poultry houses was generally higher than in pig houses, cattle houses, and mink houses. Mass concentrations of PM10 (particles with aerodynamic diameter smaller than 10 µm) was 0.83 to 4.60 mg m-3 in poultry houses, 0.13 to 1.62 mg m-3 in pigs farms, and 0.02 to 0.12 mg m-3 in cattle and mink farms. In counts, most particles (92%) inside were found smaller than 2.5 µm, whereas these particles only contributed for 2.6% to mass.

    Fine dust and coarse dust collected from broiler houses also affected specific antibody responses to a model antigen (HuSA), either declining or enhancing, depending on age of challenge and isotype measured. Components known to be part of dust and with known or expected immunologically mediating features like lipopolysaccharide (LPS), β-glucan, lipoteichoic acid, chitin, NH3, heat-dust, respectively, were used to intratracheally challenge broilers at 3 and 7 weeks of age. Especially LPS and β-glucan enhanced immune responses, but depressed body weight gain of the broilers after primary and secondary challenge. LPS also enhanced antigen-specific responses at various ages, even when administered 4 weeks prior to the antigen. After intratracheal (and also cloacal) challenge, fluorescent-labelled polystyrene beads from two sizes (1 µm and 10 µm) were present in all tissues from the broiler studied during at least one week. Such beads might have been taken up by phagocytic cells or were transferred via the blood stream.

    It was concluded that airborne particles in different sizes and with different components could alert the immune system of broilers as exemplified by enhanced primary responses in an antigen- nonspecific fashion. The absence of major effects of dust components on secondary immune responses on the other hand may indicate a regulating role of dust components on the immune system. Dust (components), however, had an important negative impact on body weight gain and heart parameters. It is concluded that there are relationships between hygienic conditions in broiler houses and immune mediated health, and as a consequence likely disease resistance and/or sensitivity to vaccination and other health management procedures. The current study urges further studies on the presence (and identification) and consequences of airborne constituents to protect health of poultry.

    Ongerief bij rundvee, varkens, pluimvee, nertsen en paarden: eerste herhaling = Discomfort among cattle, pigs, poultry, mink and horses: first repetition
    Leenstra, F.R. ; Neijenhuis, F. ; Bosma, A.J.J. ; Ruis, M.A.W. ; Smolders, E.A.A. ; Visser, E.K. - \ 2011
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 456) - 83
    rundveehouderij - varkenshouderij - pluimveehouderij - paarden - nerts - dierenwelzijn - inventarisaties - intensieve dierhouderij - dierlijke productie - melkvee - varkens - pluimvee - cattle husbandry - pig farming - poultry farming - horses - mink - animal welfare - inventories - intensive husbandry - animal production - dairy cattle - pigs - poultry
    An inventory of discomfort experienced by cattle, pigs, poultry, mink and horses in The Netherlands is carried out and compared with a similar inventory in 2007. In general, discomfort is reduced, but compared to the overall level of discomfort not to a large extent.
    Evaluation of alternative management strategies of muskrat Ondatra zibethicus population control using a population model
    Bos, D. ; Ydenberg, R.C. - \ 2011
    Wildlife Biology 17 (2011)2. - ISSN 0909-6396 - p. 143 - 155.
    experimental marshes - dynamics - habitat - harvest - mink
    Muskrats Ondatra zibethicus are considered a pest species in the Netherlands, and a year-round control programme is in effect. Currently, the agency responsible for the management of muskrat populations in the Netherlands (the LCCM) is preparing for field studies to compare alternative strategies of control. In order to decide on the specific design of such field studies, a population dynamic model was built. The model compares the current management strategy with alternatives in which the effort is focused in space or in time. The model allows us to prioritise future research questions. The major gaps in knowledge at this moment are: 1) insight into the costs of harvesting at different harvest rates, and 2) the relationship between population density on the one hand and (financial damage or) safety risk on the other hand. We suggest continuing the current management, and to test our hypothesis that intensifying harvest will lead to lower numbers of animals killed in the medium term than more extensive harvest rates. The muskrat control programme offers excellent opportunities for applied biological studies of which the benefits are likely to outweigh the costs
    Size distribution of airborne particles in animal houses
    Lai, T.L.H. ; Aarnink, A.J.A. ; Cambra-Lopez, M. ; Huynh, T.T.T. ; Parmentier, H.K. ; Groot Koerkamp, P.W.G. - \ 2011
    In: Proceedings of the XVth International Congress on Animal Hygiene, 03-07 July 2011, Vienna, Austria. - Vienna : International Society for Animal Hygiene - p. 805 - 808.
    The objective of this study was to determine concentration and size distribution of airborne particles inside and outside animal houses for broilers, broiler breeder (with bedding); layers (floor or aviary housing system); turkeys (with bedding), pigs: fatteners (traditional house, low emission houses (dry feed, or wet feed), piglets, sows (individual or group housing); cattle (cubicle house), and mink (cages). Dust concentrations, both in counts and mass, in the different particle size ranges were highest in poultry houses. The concentrations in pig houses were higher than those in cattle and mink houses. The count particle size ranges <1.0 µm was highest with average of 95%, while mass particle was highest in size ranges > 2.5 µm (on average 95%). Most count particles outside were in the size range <1.0 µm (99%). Keywords: Particle size distribution, animal houses, dust concentration
    Fijnstofemissie uit stallen: nertsen = Dust emission from animal houses: minks
    Mosquera Losada, J. ; Hol, J.M.G. ; Winkel, A. ; Huis in 'T Veld, J.W.H. ; Dousma, F. ; Ogink, N.W.M. ; Groenestein, C.M. - \ 2011
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 340) - 25
    pelsdierhouderij - nerts - fijn stof - emissie - meting - ammoniakemissie - stofbestrijding - stalklimaat - fur farming - mink - particulate matter - emission - measurement - ammonia emission - dust control - stall climate
    In this study emissions of fine dust (PM10 and PM2.5) from houses for minks were determined. In addition, emissions of ammonia, greenhouse gases and odour were determined.
    The Working Group „Integrated Protection of Fruit Crops“ is celebrating its 50th Anniversary
    Boller, E.F. ; Minks, A.K. ; Cross, J.V. ; Lenteren, J.C. van; Wildbolz, T. - \ 2010
    IOBC/WPRS Bulletin 54 (2010). - p. 193 - 217.
    The Working Group looks back at 50 years of successful work. The fruit entomologists are the pioneers within WPRS with respect to the development of integrated plant protection (IPP) and integrated production (IP) and their introduction into practice. Developments occurring during the early 1970s brought a change in the general approach reflected in the change of name in 1974 from “Integrated control in orchards” to the broader term “Integrated plant protection in orchards”. A further milestone was the establishment of the holistic concept of Integrated Production as has been described in the “Message of Ovronnaz” which should be considered as a historic landmark for IOBC as a whole. The publications of the WG reflect the broad range of its activities and its important function as scientific platform for information exchange and joint programs: 13 proceedings of International Symposia on Integrated Plant Protection and Production in orchards, 14 technical handbooks (brochures) and 41 WPRS Bulletins covering specific topics of the various subgroups. The first international symposium organised by the working group took place in Wageningen in 1961 with 36 participants from 9 countries, the most recent symposium was held in Avignon in 2008 with 250 participants and celebrating the 50th anniversary. Hundreds of experts have participated in the WG’s activities over the past 50 years. The impact of these activities on the development and application of IPP and IP in practise was and still is significant. Concepts and tools developed by the WG became not only general WPRS standards but have influenced significantly the international standards for Integrated Plant Protection. The WG has generated the approach and practical implementation of Integrated Production in the major crops of the WPRS region
    No H- and L-type cases in Belgium in cattle diagnosed with bovine spongiform encephalopathy (1999-2008) aging seven years and older
    Dobly, A. ; Langeveld, J.P.M. ; Keulen, L.J.M. van; Rodeghiero, C. ; Durand, S.V.M. ; Geeroms, R. ; Muylem, P. van; Sloovere, J. de; Vanopdenbosch, E. ; Roels, S. - \ 2010
    BMC Veterinary Research 6 (2010). - ISSN 1746-6148
    transmissible mink encephalopathy - prion protein - great-britain - atypical bse - strain variation - variant cjd - diseases - scrapie - mice - identification
    Background The bovine spongiform encephalopathy (BSE) epidemic presented homogeneity of the phenotype. This classical BSE (called C-type) was probably due to the contamination of the food chain by a single prion strain. However, due to the active surveillance and better techniques, two rare variants of BSE have been recently reported in different continents without a clear correlation to the BSE epidemic. These emerging types behave as different strains of BSE and were named H-type and L-type according to the high and low molecular mass of the unglycosylated fragment of their proteinase K resistant prion protein (PrPres). In these types, the proportion of the un-, mono- and di-glycosylated fragments of PrP (glycoprofile) is also atypical and represents an effective diagnostic parameter. This study evaluated the presence of such types in bovine of 7 years and older in Belgium. Results The Belgian BSE archive contained 41 bovines of at least 7 years of age. The biochemical features of their PrPres were analyzed by Western blot with five antibodies recognising different regions of PrPres, from N- to C-terminus: 12B2, 9A2, Sha31, SAF84 and 94B4. All antibodies clearly detected PrPres except 12B2 antibody, which is specific for N-terminal region 101-105, a PrP region that is only retained in H-types. The glycoprofiles did correspond to that of C-type (with more than 55% of diglycosylated PrPres using antibody 94B4). Therefore, all cases have the features of C-type BSE. Conclusions This study supports that, among the BSE cases of 7 years and older identified in Belgium, none was apparently of the H- or L- type. This is consistent with the very rare occurrence of atypical BSE and the restricted dimension of Belgium. These results shed some light on the worldwide prevalence of atypical BSE.
    Moeizame afhandeling nertsenverbod
    Baltussen, W.H.M. - \ 2010
    Kennis Online 7 (2010)nov. - p. 20 - 20.
    nerts - nederland - pelsdierhouderij - nadelige gevolgen - bedrijfsbeëindiging in de landbouw - mink - netherlands - fur farming - adverse effects - farm closures
    Over de sanering van de nertsenhouderij wordt al veertien jaar gesproken. Ondertussen investeren enkele pelsdierhouders al in bedrijven elders in Europa.
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