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Geen goed alternatief voor doden haantjes
Gremmen, Bart - \ 2018
animal welfare - animal production - poultry - hens - animal ethics - animal health
Stalboekje Pluimvee 2017 : Handboek voor natuurlijke pluimveegezondheidzorg met kruiden en andere natuurproducten
Groot, Maria ; Puls-van der Kamp, Ineke ; Asseldonk, Tedje van - \ 2017
Wageningen : RIKILT Wageningen University & Research (RIKILT uitgave 2017.701) - 107
pluimveehouderij - pluimvee - diergezondheid - dierenwelzijn - medicinale planten - geneeskrachtige kruiden - dierziektepreventie - dierlijke productie - biologische landbouw - handboeken - vleeskuikens - hennen - poultry farming - poultry - animal health - animal welfare - medicinal plants - herbal drugs - animal disease prevention - animal production - organic farming - handbooks - broilers - hens
De stalboekjes zijn oorspronkelijk gemaakt voor de biologische veehouderij (versies 2009 en 2011) in het kader van onderzoek voor Biokennis. Deze uitgave is in 2014 en 2015 aangevuld met nieuwe middelen en inzichten en aangepast voor toepassing in de gangbare pluimveehouderij. Dit betekent o.a. dat een hoofdstuk over vleeskuikens is toegevoegd en het leghennen stuk is uitgebreid. Het streven om het gebruik van antibiotica terug te dringen vraagt om een ander management. Goede voeding, huisvesting en hygiëne zijn hierbij belangrijk. In dit boekje worden aanwijzingen gegeven om met natuurlijke middelen de gezondheid van de dieren te bevorderen en zo ziektes te voorkomen. Tevens kunnen middelen worden ingezet om de ernst van de ziekte te reduceren. Doel is tevens om de dierenartsen te informeren over de mogelijkheden van natuurproducten en de wetenschappelijke onderbouwing hiervan inzichtelijk te maken.
Microorganism-mediated behaviour of malaria mosquitoes
Busula, Annette O. - \ 2017
University. Promotor(en): Willem Takken, co-promotor(en): Jetske de Boer. - Wageningen : Wageningen University - ISBN 9789463431156 - 199
culicidae - anopheles gambiae - anopheles arabiensis - mosquito-borne diseases - disease vectors - animal behaviour - host-seeking behaviour - plasmodium falciparum - hosts - man - cows - hens - odours - ziekten overgebracht door muskieten - vectoren, ziekten - diergedrag - gedrag bij zoeken van een gastheer - gastheren (dieren, mensen, planten) - mens - koeien - hennen - geurstoffen

Host-seeking is an important component of mosquito vectorial capacity on which the success of the other behavioural determinants depends. Blood-seeking mosquitoes are mainly guided by chemical cues released by their blood hosts. This thesis describes results of a study that determined the effect of microorganisms – host skin bacteria as well as malaria parasites – on host-seeking behaviour of female Anopheles gambiae sensu stricto and An. arabiensis in Homabay county, western Kenya. Semi-field and field experiments were conducted to determine the response of mosquitoes with different host preference to synthetic and natural odour blends from three vertebrate hosts, a human, a cow and a chicken. Screen house experiments were conducted to test whether specific skin bacteria or a mix of skin bacterial volatiles from the three vertebrate hosts mediate mosquito response. A review chapter in this thesis discusses how malaria parasites can manipulate human hosts to enhance their own transmission, by making the hosts more attractive to mosquitoes. Another experiment, using a dual-choice olfactometer, determined whether infection with malaria parasites increases human attractiveness to malaria mosquitoes, and whether the attractiveness of infected humans is Plasmodium falciparum-stage specific. Here, the same children participated in the study during infection with malaria parasites and after treatment with antimalarial drugs, artemisinin lumefantrine. Cage assays were further used to test mechanisms of attractiveness of P. falciparum-infected individuals using body odours or skin bacterial volatiles collected from the children at the two time points. Overall results show that skin bacterial volatiles play an important role in guiding mosquitoes with different host preferences to their specific host. For An. gambiae s.s., high (microscopic) densities of P. falciparum gametocytes (and not parasite-free, submicroscopic gametocytes or asexual stages of Plasmodium parasites) results into higher attractiveness of hosts, and body odours play a role in attractiveness of P. falciparum-infected humans. The results may help to develop more effective health policies and enable targeted interventions towards the most attractive hosts, which could contribute to reductions in malaria transmission. Identification of general or common attractive volatiles produced by the natural hosts as well as those from the gametocyte carriers may contribute to the development of an improved synthetic odour blend that may be used for sampling of mosquitoes with different host preferences. The use of powerful attractive odorants may result in reductions of vector-borne diseases transmitted by mosquitoes.

Uitloopkip lekkerder dan stalkip
Rodenburg, Bas - \ 2017
animal welfare - animal production - poultry - hens - animal housing

Vleeskuikens die overdag kunnen scharrelen in een wilgenbosje zijn lekkerder en sappiger dan kippen die op stal blijven. Dat concludeert een team van Vlaamse en Wageningse onderzoekers

Advancing Integrated Pest Management for Dermanyssus gallinae in laying hen facilities
Mul, Monique F. - \ 2017
University. Promotor(en): Peter Groot Koerkamp; Marcel Dicke, co-promotor(en): Bastiaan Meerburg; D.R. George. - Wageningen : Wageningen University - ISBN 9789463430036 - 194
hens - integrated pest management - dermanyssus gallinae - chicken housing - poultry housing - cages - animal production - poultry - animal health - hennen - geïntegreerde plagenbestrijding - huisvesting van kippen - pluimveehokken - kooien - dierlijke productie - pluimvee - diergezondheid

Pest and diseases in agricultural systems reduce the yield and quality of available food and feed worldwide. To meet the global growing demand for these products, losses should be reduced, preferably in a sustainable way. Integrated Pest Management (IPM) is a sustainable method that aims to minimize economic losses due to pests and diseases. IPM is generally based on eight steps: 1) prevention, 2) monitoring, 3) Decision‐making based on monitoring and thresholds, 4) use of non‐chemical methods, 5) pesticide selection, 6) reduced pesticide use, 7) anti‐resistance strategies, and 8) evaluation. With these steps, it is possible to prevent and control pests and diseases whilst deploying pesticides only as a last resort, thus reducing issues with pesticide contamination and resistance. Implementation of IPM by farmers increases when it is clear that it is compatible with existing farm processes and that it results in benefits for them.

Successful IPM is most commonly applied against pests and diseases in crop production. When comparing the number of research articles on IPM in crop production with the number of research articles on IPM in animal production, it becomes clear that a paucity of scientific papers have been published on the latter. In laying hen facilities, for example, the application of all but basic IPM is still rare, even though the benefits of IPM have been described for poultry pests and disease vectors. In laying hen facilities Dermanyssus gallinae (PRM=poultry red mite), an hematophagous parasite, is common in many parts of the world. This mite is hard to control and negatively affects hen health, ‐welfare and farm economics, with estimated costs of infestation reaching 130 million euro per year in Europe. Currently, implementation of IPM for D. gallinae in laying hen facilities is limited to some combination of cleaning between flocks, limited preventive measures, and application of chemically or physically acting products. Implementation of more advanced IPM programmes for D. gallinae should therefore be considered to improve control prospects for this pest in laying hen facilities.

This thesis focuses on the knowledge necessary for advancing IPM for D. gallinae in laying hen facilities. More specifically it focuses on prevention, monitoring and population modelling of this significant pest, with preventive measures and monitoring being key in advancing IPM per se.

Knowledge assessment. To develop IPM for D. gallinae in laying hen facilities, biological and ecological knowledge of D. gallinae and knowledge of the effects of biotic and a‐biotic factors on this pests’ population development are required (Chapter 2). Therefore, a seminar was organized with eighteen D. gallinae researchers, from eight different European countries, with the aim of amassing existing expertise. This seminar gave insight into the current knowledge and knowledge gaps, regarding D. gallinae, also informing future perspectives and required developments for improving control of D. gallinae in laying hen facilities. During four sessions, the researchers present discussed lifecycle issues, effects of D. gallinae on hen and egg production, monitoring methods for D. gallinae infestations in laying hen facilities and control methods for D. gallinae in laying hen facilities. It was concluded that, where the D. gallinae lifecycle is concerned, a lot is still unknown about the mites feeding behaviour and preferences, mating behaviour, survival and conditions required for reproduction, host finding, aggregation cues, and attractant and repellent substances. When focusing on the effects of D. gallinae on the hen and on egg production it was agreed that a D. gallinae infestation is likely to result in higher water intake, lower egg production, lower feed conversion, increase of the immune response and reduced feather quality. It was also suggested that these effects may be hen genotype dependent, and further noted that effects are rarely quantified and need further investigation. Though monitoring was considered to be most important to improve control of D. gallinae, it was concluded that the available monitoring methods only indicate trends and a robust monitoring plan is lacking. The participants considered heating the hen house combined with a chemical treatment to be the most promising control method. Future promising developments for control of D. gallinae were considered to be use of vaccination, predatory mites and entomopathogenic fungi. The effects of D. gallinae on human health were not extensively discussed, but it was concluded that D. gallinae can be of medical significance, either directly via reaction to mite bites, or indirectly via human exposure to the chemicals used to control D. gallinae.

Prevention. To acquire knowledge on the routes of introduction and spread of D. gallinae in laying hens facilities, the Hazard Analysis and Critical Control Points (HACCP) system was used (Chapter 3). The structure of this system allows the user to identify the risk factors and the critical control points for the introduction and spread of pathogens and parasites. This method was further used to identify preventive and corrective actions against D. gallinae. Four experts identified 41 hazards for introduction and spread of D. gallinae in laying hen facilities. To prevent these hazards, these experts made several suggestions for corrective actions. The risks of 41 hazards were calculated by multiplying the likelihood (1= occurring seldomly/theoretically; 2= occurring approximately once a year; 3= occurring repeatedly/more than once a year) by the severity (1 = low / single place in the facility becomes infested with D. gallinae; 2= moderate/ facility becomes infested at more than one location; 3= high/ D. gallinae infestation occurs at almost all places within the laying hen facility) of infestation. Hazards with a risk above 3, or with a severity of 3, were regarded as Critical Control Points (CCP’s). The CCP’s with the highest risks (risk of 6 and higher) for introduction of D. gallinae in laying hen facilities were: introduction of new flocks, containers and crates, the farmer and their employees. The CCP’s with the highest risks (risk of 6 and higher) for spread of D. gallinae between laying hen facilities were mice, rats and flies, wild birds, the feeding system, shared material and equipment, the egg conveyer belt, manure aeration pipes, removal of cadavers, visitors and external personnel, the farmer and their employees. The critical limits, a procedure step of the HACCP system which will be followed by a corrective action when the limit is exceeded, could not be determined as a result of lack of knowledge about thresholds. Subsequently, suggestions were made for monitoring the mite population and for documentation and validation. A checklist was devised using the corrective action from the CCP’s with the highest risks. This management tool for layer farmers was evaluated by UK and Dutch layer farmers as feasible and useful.

Monitoring. The approach of Reflexive Interactive Design (RIO) was used to design an automated monitoring tool for D. gallinae, including an automated mite detection sensor (Chapter 6). The approach generated effective and technically feasible solutions for the key functions of the automated mite detection sensor, these being 1) the assessment of the D. gallinae population, 2) localizing the location and assessing the time of detection and 3) removal of mites from the detection area. Three different design concepts were designed using these solutions. As an additional, albeit proven essential step to the RIO approach, the main solutions were tested with live mites ensuring the alignment of solutions with the biology and behaviour of D. gallinae in vivo. A combination of the best solutions were developed in two different prototypes. These prototypes were subsequently tested in the laboratory and on farm. The prototype situated under the perch, with a through beam sensor and a pump to remove mites from the sensor after recording, was the most successful model. The designed automated mite detection sensor, or automated mite counter, for D. gallinae was subsequently validated in experimental laying hen cages with live birds and a growing population of D. gallinae (Chapter 5). The study resulted in 17 data points, each being a combination of ‘number of mites counted’ by the automated mite counter and the ‘number of mites present’ in the experimental laying hen cages. The regression line between the ‘number of mites counted’ and the ‘number of mites present’ demonstrated that the automated mite counter was able to track the D. gallinae population effectively.

Population modelling. Step 2 of IPM describes not only pest monitoring in the field, but also ‘scientifically sound warning, forecasting and early diagnosis systems, where feasible, as well as the use of advice from professionally qualified advisors’. To advance this step for D. gallinae we developed and demonstrated an operational model, forecasting the mite population dynamics and evaluating and forecasting the effect of a treatment application for D. gallinae in laying hen facilities. For IPM this model and the required inputs need to be 1) labour‐extensive with minimal staff input, preferably automatically implementing “real time” measurement data into models; 2) operational, providing easily interpretable data, forecasting pest population dynamics and the moment a threshold will be exceeded; 3) able to compensate for different locations and time‐specific‐interactions and variables (e.g. management and temperature), enabling the handling of variability of the parameters of interest; 4) able to identify pest hotspots; 5) able to estimate and forecast treatment efficacy; and 6) applicable for different monitoring methods and therefore able to correct for monitoring measurement errors. Prior to the development of the population dynamics model a high variation in population growth was found which could be only partly explained by temperature, flock age, treatment, and compartment/laying hen facility. A substantial part of the total variation remained unexplained, or was found to be temporal. As a result of this partly temporal variation, a dynamic approach was suggested to improve the forecasting quality of a population dynamics model. With the input of population monitoring data, temperature data and information of the dates of any D. gallinae treatment interventions, the developed model was able to forecast the population dynamics of D. gallinae post treatment and without treatment while compensating for location and time specific interactions, handling the variability of the parameters. Moreover, this population dynamics model was able to forecast the D. gallinae population using data from different monitoring methods. Together with the models compatibility with different housing systems and its ability to forecast the mite population dynamics (requiring only three relative easy obtainable parameters), this model is an improvement over existing approaches for forecasting D. gallinae that could contribute to steps 2 and 8 of IPM for D. gallinae in laying hen facilities.

The results from this study directly facilitate advanced IPM programmes for D. gallinae in laying facilities. The new ‘products’ developed are tools for prevention, monitoring, forecasting population dynamics and evaluating treatment effects, representing the requirements of IPM steps 1, 2, and 8. Indirectly the results may accelerate the development of new control measures, with knowledge acquired through use of the developed products it also is likely to contribute to IPM steps 3, 4, 6 and 8 in the future; e.g. the determination of an action threshold, and a tool advising farmers on the most effective and economic time for applying a corrective action or hotspot treatment for D. gallinae.

With the obtained knowledge and new products implemented to control D. gallinae in laying hen farms, major advances can be made in IPM for this pest. More specifically, as a result of this work IPM for D. gallinae in laying hen facilities can be advanced by the identification of preventative control measures, the development of an automated monitoring tool and a model forecasting mite population dynamics and evaluating applied treatments. Consequently, the results of this study can be expected to improve hen health, welfare and farm economics for the egg production industry. In the future, advances in other IPM programmes can be expected when the obtained knowledge, tools and methods are transferred to other pest species in multiple sectors.

Handelingsperspectief voor pluimveehouders in de preventie van laag- en hoogpathogene vogelgriep (AI)
Bokma, Martien ; Bergevoet, Ron ; Elbers, Armin ; Goot, Jeanet van der; Neijenhuis, Francesca ; Niekerk, Thea van; Leenstra, Ferry - \ 2016
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 998) - 42
aviaire influenza - hennen - pluimveehouderij - boeren - dierziektepreventie - risicofactoren - avian influenza - hens - poultry farming - farmers - animal disease prevention - risk factors
Committed by the Dutch poultry sector research is carried out concerning acting perspective for prevention of AI-introduction on poultry farms, based on existing knowledge. The findings are shown in two parts: part I with practical advices for poultry farmers, and part II with its underpinning with a summary of existing knowledge of risk factors, preventive measures, early detection and possibilities for promoting desired (preventive) behaviour.
Effect van strooiselverwijdering bij leghennen in volièrehuisvesting op de emissie van ammoniak, geur, broeikasgassen en fijnstof
Mosquera, J. ; Emous, R. van; Hattum, Theo van; Nijeboer, G. ; Hol, J.M.G. ; Dooren, H.J. van; Ogink, N.W.M. - \ 2016
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 995) - 69
dierenwelzijn - dierlijke productie - pluimvee - hennen - huisvesting, dieren - diergezondheid - animal welfare - animal production - poultry - hens - animal housing - animal health
This report summarizes the results of measurements performed in the framework of the programmatic Approach nitrogen (PAS) to determine the effect of removing litter from livestock housing of laying hens (to maintain a thin layer of litter in the animal building) on the emission of ammonia, fine dust, odour and greenhouse gases (methane, nitrous oxide). Removing the litter led to significantly lower emissions of NH3 and PM10 (on average 20-22% lower emissions). Although in seven of all nine measurements removing the litter resulted in lower odour emissions (~25% emission reduction), no significant effect was found of removing the litter on odour removal. For CH4 and N2O, removing litter did not result in significantly lower emissions. When a thin litter layer (less than 2-3 cm) can be maintained, a reduction of 25-35% in NH3 and PM10 emissions may be achieved.
Het haantje weer op de kaart
Leenstra, Ferry - \ 2016
animal welfare - animal production - chicks - hens - animal ethics - animal health

Mannelijke kuikens van legkippen leven niet langer dan een dag. Om die verspilling tegen te gaan, wordt geprobeerd het vlees van deze haantjes weer op tafel te krijgen. Met succes maar voorlopig is het beter te voorkomen dat deze haantjes het levenslicht zien.

Disentangling the domestic contract : understanding the everyday-life construction of acceptability -or non-acceptability- of keeping and killing animals for food
Nijland, Hanneke J. - \ 2016
University. Promotor(en): Cees van Woerkum; Noelle Aarts. - Wageningen : Wageningen University - ISBN 9789462578296 - 325
meat - vegetarians - vegetarianism - vegetarian diets - killing of animals - meat animals - meat production - households - environmental impact - sustainability - animal welfare - animal production - animal ethics - food - dairy cattle - beef cattle - pigs - poultry - broilers - hens - vlees - vegetariërs - vegetarisme - vegetarische diëten - doden van dieren - slachtdieren - vleesproductie - huishoudens - milieueffect - duurzaamheid (sustainability) - dierenwelzijn - dierlijke productie - dierethiek - voedsel - melkvee - vleesvee - varkens - pluimvee - vleeskuikens - hennen

When we were children learning the names of animals, farm utensils and food products from picture books, talking about farming animals and related food products appeared simple. However, the intricate realities of modern-day farming practices differ momentously from this primary reference - the picture books. The topic brings about polarized responses, both rationally and emotionally, reflecting very diverse outlooks on the world. This dissertation reports on a research, set in the Netherlands and Turkey, that was designed to improve our understanding of the everyday-life construction of the acceptability -or non-acceptability- ofkeeping and killing animals for food, or in other words: to disentangle the domestic contract.

Are all eggs equal? : embryonic development and nutrient metabolism in chicken eggs of different origins
Nangsuay, A. - \ 2016
University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; R. Meijerhof. - Wageningen : Wageningen University - ISBN 9789462577749 - 213 p.
eggs - hens - broilers - characteristics - strains - embryonic development - nutrients - metabolism - hatcheries - poultry - nutrition physiology - eieren - hennen - vleeskuikens - karakteristieken - stammen (biologisch) - embryonale ontwikkeling - voedingsstoffen - metabolisme - broedinstallaties - pluimvee - voedingsfysiologie

Hatching eggs, supplied to hatcheries are originating from different origins varying in breed, strain, and breeder age. These hatching eggs can be different in size, composition and eggshell properties, which might influence nutrient and O2 availability and consequently could affect embryonic development and nutrient metabolism. The aim of this thesis was therefore 1) to investigate effects of egg origin on nutrient and O2 availability, 2) to investigate effects of egg origins on nutrient metabolism and embryonic development and 3) to investigate consequences of different egg origins on the incubation process and hatching characteristics. In five studies, effects of different egg origins on nutrient and O2 availability, nutrient metabolism, embryo development and hatching characteristics were investigated. The first and second study focused on breeder age and egg size. The third study on breed; broilers and layers. The fourth study on broiler strain and the fifth study on breeder age, strain and eggshell temperature (EST). The overall findings in this thesis suggest that hatching eggs from different origins are not equal in availability of nutrients and O2. Nutrient availability is altered through variation in yolk size, especially by the effects of breeder age and breed. O2 availability is altered by differences in eggshell properties, which is influenced by especially breed and broiler strain. The availability of both nutrients and O2 plays a role on nutrient metabolism measured as embryonic heat production (HP) and consequently on embryonic development. Between incubation day (E) E7 and E14, both nutrient and O2 availability might affect nutrient metabolism as shown in the results of the broiler and layer comparison. Between E14 and hatching, the availability of O2 becomes the most determinant factor for nutrient metabolism and consequently for embryonic development. An increase in EST from 37.8 to 38.9°C from E7 onward resulted in an acceleration of nutrient metabolism and embryonic development until E16, but thereafter a high EST resulted in reduced yolk free body mass development. Embryos with an accelerated metabolic speed at an early stage of incubation, caused by an increased EST, might reach limited O2 availability at a higher magnitude than the embryos at a normal EST. As a result, nutrient metabolism is restricted and embryonic development is depressed. It can be concluded that not only the HP, but also the availability of O2 is crucial to be taken into account for developing incubator temperature. The principle is to obtain an optimal EST, which could maintain the balance between O2 requirement (driven by nutrient metabolism) and O2 availability for a continuing optimal nutrient metabolism to generate sufficient energy for embryonic development throughout incubation.

Effects of early life conditions on immunity in broilers and layers
Simon, K. - \ 2016
University. Promotor(en): Bas Kemp, co-promotor(en): Aart Lammers. - Wageningen : Wageningen University - ISBN 9789462576711 - 188 p.
broilers - hens - ontogeny - poultry feeding - chicken housing - immune response - antibiotics - gastrointestinal microbiota - immunology - immunity - vleeskuikens - hennen - ontogenie - pluimveevoeding - huisvesting van kippen - immuniteitsreactie - antibiotica - microbiota van het spijsverteringskanaal - immunologie - immuniteit

ABSTRACT

The course for later life immune responses is set early in life during the developmental phase of the immune system and accordingly disturbances of immune development may have long-term consequences for host health. In terms of immune activation and immune development the gut microbiota play an important role and consequently disturbances of early life microbial colonization may affect host immunity later in life. In chickens, disturbances of microbial colonization may be caused by various early life conditions which in turn may affect robustness of the chick in the long term. The aim of this thesis was to assess the effects of several early life factors including time of access to feed post hatch (immediately or 72 hours delayed), housing conditions, antibiotic treatment, and intestinal pathology on the intestinal microbiota composition, immune development, and specific antibody response later in life in chickens. Additionally, possible differences between broilers and layers were taken into account as unintentional co-selection of immunological traits may have taken place during the selection process for different production traits. Delayed access to feed and administration of antibiotics early in life led to a shift in early life microbiota composition, which seemed to be restored quite quickly in both cases. Microbiota composition in response to DSS was not investigated, but based on rodent studies was expected to be influenced. Ileal immune development, which was assessed in terms of relative cytokine and immunoglobulin mRNA expression levels was not affected by feeding strategy post hatch (early vs. delayed), but a downregulation of ileal immunoglobulin expression levels could be observed during DSS treatment. All early life factors investigated affected the specific antibody response towards an immunological challenge later in life. Interestingly, there seemed to be an interaction between immediate access to feed post hatch and immune responsiveness towards the environment, thus early feeding may influence the adaptive capacity of chickens in different environments. Regarding the differences between breeds it is interesting to note that broilers seem to have developed a more humoral oriented immune strategy, while layers seem to react in a more pro-inflammatory way. Taken together, results suggested that early life conditions may influence priming of the immune system during its developmental phase, leading to altered antibody responses later in life. Furthermore, broilers and layers seem to have developed different immune strategies. Early life conditions as well as possible differences between breeds should therefore be taken into account in future immunological studies.

Genomic selection in egg-laying chickens
Heidaritabar, M. - \ 2016
University. Promotor(en): Martien Groenen, co-promotor(en): John Bastiaansen. - Wageningen : Wageningen University - ISBN 9789462576704 - 220 p.
hens - genomics - genetic variation - selective breeding - quantitative traits - breeding value - animal genetics - animal breeding - hennen - genomica - genetische variatie - selectief fokken - kwantitatieve kenmerken - fokwaarde - diergenetica - dierveredeling

Abstract

Heidaritabar, M. (2016). Genomic selection in egg-laying chickens. PhD thesis, Wageningen University, the Netherlands

In recent years, prediction of genetic values with DNA markers, or genomic selection (GS), has become a very intense field of research. Many initial studies on GS have focused on the accuracy of predicting the genetic values with different genomic prediction methods. In this thesis, I assessed several aspects of GS. I started with evaluating results of GS against results of traditional pedigree-based selection (BLUP) in data from a selection experiment that applied both methods side by side. The impact of traditional selection and GS on the overall genome variation as well as the overlap between regions selected by GS and the genomic regions predicted to affect the traits were assessed. The impact of selection on genome variation was assessed by measuring changes in allele frequencies that allowed the identification of regions in the genome where changes must be due to selection. These frequency changes were shown to be larger than what could be expected from random fluctuations, indicating that selection is really affecting the allele frequencies and that this effect is stronger in GS compared with BLUP. Next, concordance was tested between the selected regions and regions that affect the traits, as detected by a genome-wide association study. Results showed a low concordance overall between the associated regions and the selected regions. However, markers in associated regions did show larger changes in allele frequencies compared with the average changes across the genome. The selection experiment was performed using a medium density of DNA markers (60K). I subsequently explored the potential benefits of whole-genome sequence data for GS by comparing prediction accuracy from imputed sequence data with the accuracy obtained from the 60K genotypes. Before sequencing, the selection of key animals that should be sequenced to maximize imputation accuracy was assessed with the original 60K genotypes. The accuracy of genotype imputation from lower density panels using a small number of selected key animals as reference was compared with a scenario where random animals were used as the reference population. Even with a very small number of animals as reference, reasonable imputation accuracy could be obtained. Moreover, selecting key animals as reference considerably improved imputation accuracy of rare alleles compared with a set of random reference animals. While imputation from a small reference set was successful, imputation to whole-genome sequence data hardly improved genomic prediction accuracy compared with the predictions based on 60K genotypes. Using only those markers from the whole-genome sequence that are more likely to affect the phenotype was expected to remove noise from the data, but resulted in slightly lower prediction accuracy compared with the complete genome sequence. Finally, I evaluated the inclusion of dominance effects besides additive effects in GS models. The proportion of variance due to additive and dominance effects were estimated for egg production and egg quality traits of a purebred line of layers. The proportion of dominance variance to the total phenotypic variance ranged from 0 to 0.05 across traits. Also, the impact of fitting dominance besides additive effects on prediction accuracy was investigated, but was not found to improve accuracy of genomic prediction of breeding values.

Vermarkten van haantjes van legrassen : Samenvatting van en vervolg op rapport 739 (2013,Wageningen UR Livestock Research)
Leenstra, F.R. ; Steverink, M.H.A. ; Niekerk, T.G.C.M. van - \ 2016
Wageningen UR Livestock Research (Livestock Research rapport 937) - 29 p.
kuikens - hanen - hennen - slachtdieren - dubbel-doel rassen - markten - dierenwelzijn - dierlijke productie - pluimvee - dierethiek - diergezondheid - chicks - cocks - hens - meat animals - dual purpose breeds - markets - animal welfare - animal production - poultry - animal ethics - animal health
Licht op licht: licht en verlichting in de pluimveehouderij in relatie tot beschadigend pikgedrag
Niekerk, T.G.C.M. van; Ellen, H.H. ; Winkel, A. - \ 2015
Livestock Research Wageningen UR (Livestock Research rapport 922) - 33 p.
pluimvee - licht - lichtregiem - gezichtsvermogen - verenpikken - pluimveehouderij - dierenwelzijn - dierlijke productie - hennen - huisvesting, dieren - diergezondheid - diergedrag - poultry - light - light regime - vision - feather pecking - poultry farming - animal welfare - animal production - hens - animal housing - animal health - animal behaviour
In this report an overview is given of the technical knowledge with regards to light. light sources and the vision of poultry. Recent developments in lighting of poultry houses are mainly focused on new light sources, specifically LED, and the presence of daylight. Daylight comprises UV, which for poultry is a visual part of the spectrum. Chickens also see better in the red and green-blue spectrum. Technically it is possible to make lamps in the desired spectrum, but there is insufficient knowledge of the demands of the bird to be able to tune the lamps to their needs.
Vrijheid & blijheid voor de leghen : inspirerende alternatieven voor de buitenuitloop
Niekerk, T.G.C.M. van; Mul, M.F. ; Hommes, M. - \ 2015
Wageningen UR Livestock Research
hennen - pluimveehouderij - uitloop - duurzame veehouderij - huisvesting van kippen - innovaties - dierenwelzijn - dierlijke productie - pluimvee - diergedrag - hens - poultry farming - outdoor run - sustainable animal husbandry - chicken housing - innovations - animal welfare - animal production - poultry - animal behaviour
Binnen het project ‘Inrichting Buitenuitloop Pluimvee’ is gezocht naar nieuwe, vermarktbare concepten voor de legpluimveehouderij op basis van een uitloop zonder de huidige milieu en diergezondheidsnadelen. Tijdens een workshop hebben ketenpartijen, pluimveehouders, glastuinders, ontwerpers en onderzoekers gezamenlijk gebrainstormd over de mogelijkheden. De ontwerpen in deze brochure zijn het resultaat van die workshop.
Gelijkspel
Bestman, M.W.P. ; Verwer, C.M. ; Leenstra, F.R. ; Niekerk, T.G.C.M. van; Reuvekamp, B.F.J. - \ 2015
De Pluimveehouderij 43 (2015)11. - ISSN 0166-8250 - p. 29 - 29.
pluimveehouderij - snavelkappen - verenkleed - hennen - uitloop - biologische landbouw - dierenwelzijn - verenpikken - pluimvee - dierlijke productie - diergedrag - diergezondheid - poultry farming - debeaking - plumage - hens - outdoor run - organic farming - animal welfare - feather pecking - poultry - animal production - animal behaviour - animal health
Onderzoek weerspreekt dat kippen met onbehandelde snavels eerder kaal en kaler worden dan behandelde hennen, zoals vaak wordt gesteld. Er is weinig verschil in verenkleed tussen bio- en vrije-uitloophennen.
Praktijkmonitor ook in de legsector
Niekerk, T.G.C.M. van - \ 2015
De Pluimveehouderij 45 (2015)8. - ISSN 0166-8250 - p. 26 - 27.
pluimveehouderij - hennen - dierenwelzijn - diergezondheid - monitoring - diergedrag - verenpikken - dierlijke productie - pluimvee - poultry farming - hens - animal welfare - animal health - animal behaviour - feather pecking - animal production - poultry
Als voorbereiding op het naderend verbod op ingrepen, wordt bij (opfok)leghennen, net als bij vleeskuikenouderdieren, (praktijk)kennis vergaard. Om met die kennis de status en mogelijkheden van het houden van leghennen zonder bepaalde ingrepen in kaart te brengen.
Radio en kleurige overalls helpen tegen verenpikken
Rodenburg, T.B. - \ 2015
WageningenWorld (2015)2. - ISSN 2210-7908 - p. 7 - 7.
hennen - kippen - verenpikken - diergedrag - stressfactoren - dierenwelzijn - geluiden - radio - kleur - diergezondheid - dierlijke productie - pluimvee - hens - fowls - feather pecking - animal behaviour - stress factors - animal welfare - sounds - colour - animal health - animal production - poultry
Wageningen University heeft samen met de Universiteit Utrecht en de Rijksuniversiteit Groningen manieren gevonden om verenpikken bij leghennen tegen te gaan. Dat biedt perspectief bij het verbod op snavelkappen dat in 2018 van kracht wordt.
Stalboekje pluimvee 2015 : handboek voor natuurlijke pluimveegezondheidszorg met kruiden en andere natuurproducten
Groot, M.J. ; Puls-van der Kamp, I. ; Asseldonk, T. van - \ 2015
Wageningen : RIKILT Wageningen UR - 112
pluimveehouderij - pluimvee - diergezondheid - dierenwelzijn - medicinale planten - geneeskrachtige kruiden - dierziektepreventie - dierlijke productie - biologische landbouw - handboeken - vleeskuikens - hennen - poultry farming - poultry - animal health - animal welfare - medicinal plants - herbal drugs - animal disease prevention - animal production - organic farming - handbooks - broilers - hens
In dit boekje worden aanwijzingen gegeven om met natuurlijke middelen de gezondheid van de dieren te bevorderen en zo ziektes te voorkomen. Tevens kunnen middelen worden ingezet om de ernst van de ziekte te reduceren. Doel is tevens om de dierenartsen te informeren over de mogelijkheden van natuurproducten en de wetenschappelijke onderbouwing hiervan inzichtelijk te maken
Estimating requirements for apparent faecal and standardised ileal digestible amino acids in laying hens by a metaanalysis approach
Krimpen, M.M. van; Veldkamp, T. ; Riel, J.W. van; Khaksar, V. ; Hashemipour, H. ; Blok, M.C. ; Spek, W. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock research report 848) - 71
hennen - aminozuren - voer - meta-analyse - verteerbaarheid - eiwitverteerbaarheid - dunne darm - voedingsstoffengehalte - voedingsstoffenbehoeften - voedingsbehoeften - pluimvee - pluimveevoeding - hens - amino acids - feeds - meta-analysis - digestibility - protein digestibility - small intestine - nutrient content - nutrient requirements - feed requirements - poultry - poultry feeding
The aim of the present study is to update the requirements for the essential amino acids of laying hens, both on a AFD and SID basis, by performing a meta-analysis on dose-response studies used to derive requirement values for essential amino acids (lysine, methionine+cysteine, threonine and tryptophan) in laying hens as presented in the literature. In this meta-analysis, the data are fitted by use of the Wood equation (see paragraph 2.4). The amino acid intake levels for realizing maximal rate of lay, egg mass and feed efficiency are provided. The amino acid requirements for use in practice are based on the amino acid intake levels at which 95% of these maximum responses were reached.
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