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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    Transhumant pastoralism in a changing world : Challenges and opportunities to sustainable yak farming in Bhutan
    Dorji, Nedup - \ 2020
    Wageningen University. Promotor(en): P.W.G. Groot Koerkamp, co-promotor(en): E.A.M. Bokkers; M. Derks. - Wageningen : Wageningen University - ISBN 9789463954464 - 150
    Efficacy of management and monitoring methods to prevent post‐harvest losses caused by rodents
    Krijger, Inge M. ; Gort, Gerrit ; Belmain, Steven R. ; Groot Koerkamp, Peter ; Shafali, Rokeya B. ; Meerburg, Bastiaan G. - \ 2020
    Animals 10 (2020)9. - ISSN 2076-2615 - p. 1 - 19.
    Bandicota bengalensis - Grain store - Post‐harvest losses - Rattus rattus - Rice - Rodent management

    The presence of pest rodents around food production and storage sites is one of many underlying problems contributing to food contamination and loss, particularly influencing food and nutrition security in low‐income countries. By reducing both pre‐ and post‐harvest losses by rodents, millions of food‐insecure people would benefit. As there are limited quantitative data on post‐harvest rice losses due to rodents, our objectives were to assess stored rice losses in local households from eight rural communities and two rice milling factories in Bangladesh and to monitor the effect of different rodent control strategies to limit potential losses. Four treatments were applied in 2016 and 2017, (i) untreated control, (ii) use of domestic cats, (iii) use of rodenticides, (iv) use of snap‐traps. In total, over a two‐year period, 210 rodents were captured from inside people’s homes, with Rattus rattus trapped most often (n = 91), followed by Mus musculus (n = 75) and Bandicota bengalensis (n = 26). In the milling stations, 68 rodents were trapped, of which 21 were M. musculus, 19 R. rattus, 17 B. bengalensis, 8 Rattus exulans, and 3 Mus terricolor. In 2016, losses from standardised baskets of rice within households were between 13.6% and 16.7%. In 2017, the losses were lower, ranging from 0.6% to 2.2%. Daily rodent removal by trapping proved to be most effective to diminish stored produce loss. The effectiveness of domestic cats was limited.

    Herders and livestock professionals' experiences and perceptions on developments and challenges in yak farming in Bhutan
    Dorji, Nedup ; Derks, Marjolein ; Dorji, Phub ; Groot Koerkamp, Peter W.G. ; Bokkers, Eddie A.M. - \ 2020
    Animal Production Science (2020). - ISSN 1836-0939
    policy - welfare

    Context: The yak-based transhumant system is influenced by socioeconomic developments, regulations and environmental changes. Little is known about the impact of this on yak farming practices among different regions in Bhutan. Aim and methods: The experienced changes in yak farming practices over the years and perceptions on developments were assessed through interviews with yak herders in three regions (west, n = 22; central, n = 20; east, n = 25) and with livestock extensionists (n = 28). Key results: At present, forage shortage in the rangeland, yak mortality mainly due to (endangered) wild predators and, to a lesser extent, labour availability are the main concerns in all yak farming regions. These concerns have increased due to socioeconomic developments (e.g. education and other sources of income) and strong conservation policy, which affects the living environment of the yaks. Overall, the market to sell yak products and livestock extension services has improved, but forage shortage and yak mortality has increased over the years. However, some factors causing forage shortage are more specific to certain regions, e.g. competition with the horse population (west), cattle and cattle-yak hybrids (east), cordyceps collection (west and central) and prohibited burning of rangelands (central and east). Family labour available to herd yaks has slightly decreased, and the number of young family members (successors) to take over yak farming has decreased over the years. Conclusions: On the basis of the experiences and perceptions of yak herders and extensionists, we conclude that increasing forage shortage in the rangelands, decreasing numbers of successors, and increasing yak predation by wild animals are the major threats to yak farming. Implications: This study demonstrates that yak farming in Bhutan experiences an increasing pressure to sustain. Differences between regions make clear that a one blanket-policy will not be effective to preserve yak farming for the future.

    The future of yak farming from the perspective of yak herders and livestock professionals
    Dorji, Nedup ; Derks, Marjolein ; Groot Koerkamp, Peter W.G. ; Bokkers, Eddie A.M. - \ 2020
    Sustainability 12 (2020)10. - ISSN 2071-1050
    Future - Opinions - Perceived concern - Sustainability - Yak farming

    The declining number of yak farming families is perceived as a socio-political and economic concern in Bhutan. However, there is limited understanding of what influences herders' plans and decisions on yak farming. We studied factors determining future perspectives of yak farming by interviewing yak herders and livestock professionals. We analysed relationships between herders' characteristics and level of concerns, and future plans related to yak farming. Furthermore, relationships between level of concern and future plans were analysed. Most of the herder characteristics did not influence their future plans with yak farming. Age and level of perceived concern of the herders was associated with their wish for their children to continue yak farming in the future. Nevertheless, they expect that the number of yak farming families will decline in the next ten years. Additionally, most of the livestock professionals believe that the number of yak farming families will decline in the future. No differences were observed between the aggregated score of concern of herders and livestock professionals. The most important factors threatening the future of yak farming in Bhutan according to herders and livestock professionals are forage shortage, predation and no successor to take up yak farming.

    Wild rodents and insectivores as carriers of pathogenic Leptospira and Toxoplasma gondii in The Netherlands
    Krijger, Inge M. ; Ahmed, Ahmed A.A. ; Goris, Maria G.A. ; Cornelissen, Jan B.W.J. ; Groot Koerkamp, Peter W.G. ; Meerburg, Bastiaan G. - \ 2020
    Veterinary Medicine and Science 6 (2020)3. - ISSN 2053-1095 - p. 623 - 630.
    leptospirosis - mice - pathogen–host relationship - rats - reservoir - zoonoses

    Small mammals such as rodents can to carry zoonotic pathogens. Currently, there is impaired knowledge on zoonotic pathogens in rodents and insectivores in the Netherlands. This limits opportunities for preventive measures and complicates risk-assessments for zoonotic transmission to humans. Leptospira spp. and Toxoplasma gondii are present on a list of prioritized emerging pathogens in the Netherlands and were therefore the focus of this study. Both pathogens have the ability to survive under moist environmental conditions. In total, a group of 379 small mammals (rodents & insectivores) were tested on pathogenic Leptospira spp., and 312 on T. gondii. Rodents and insectivores were trapped at various sites, but mostly on pig and dairy farms throughout the country. Over five percent of the animals (5.3%, n = 379) tested positive for Leptospira DNA, and five of the animals (1.6%, n = 312) tested were positive for T. gondii DNA. The animals positive for T.gondii were all brown rats and the ones for Leptospira spp. were various species. Our results show that insectivores and rodents might be used as an indicator for the environmental contamination and/or the contamination in wildlife for Leptospira spp.

    Herders’ and livestock professionals’ experiences on past and future developments in yak farming in Bhutan
    Dorji, Nedup ; Derks, M. ; Dorji, P. ; Groot Koerkamp, P.W.G. ; Bokkers, Eddie - \ 2020
    In: Wias Annual Conference 2020. - WIAS - p. 48 - 48.
    In Bhutan yak-based transhumant systems are influenced by socioeconomic developments,regulations, and environmental changes. Little is known about the impact of thesefactors on yak farming practices. The aim was to study perceptions and experiences ofyak herders and livestock professionals on past and future developments in yak farming.Yak herders in three regions (west, n = 22; central, n = 20; east, n = 25) and livestock professionals(n = 28) were interviewed using a semi-structured questionnaire. Our results showthat at present forage shortage in the rangeland (herders, 93%; livestock professionals,96%), yak mortality (herders, 96%; livestock professionals, 96%) and to a lesser extent labouravailability (herders, 30%; livestock professionals, 96%) are the main concerns in yakfarming. Some factors causing forage shortage, however, are specific to certain regions,e.g. competition with the horse population (west, 91%) and prohibited burning of rangelands(central, 80%; east, 76%). Overall, the market to sell yak products and livestock extensionservices has improved, whereas forage shortage and yak mortality has increased over the years. In addition, family labour available to herd yaks, as well as the number of young family members to take over yak herding has decreased over the years. These key concerns have increased due to socioeconomic developments and strong conservation policy, which also affects the living environment of the yaks. Despite the challenges experienced by herders in yak farming, the majority of herders (81%) wish their children to take up yak farming in the future. About half of the respondents (57%), however, think that yak farming households will decline in the next 10 years. For a sustainable future of yak farming in Bhutan active policy involvement seems to be required to reduce uncertainties and increase livelihood perspectives.
    The effect of gas to liquid ratio on carbon dioxide removal and heat loss across a forced ventilated trickling filter
    Karimi, Davood ; Eding, Ep ; Aarnink, Andre J.A. ; Groot Koerkamp, Peter ; Verreth, Johan - \ 2020
    Aquacultural Engineering 88 (2020). - ISSN 0144-8609
    Carbon dioxide stripping - Degassing - Energy - Forced ventilation - Gas:Liquid ratio (GLR) - Heat - Nitrification - RAS - Trickling filter (TF)

    The objective of this study was to investigate the effect of the gas: liquid ratio (GLR) on carbon dioxide removal and heat loss across a forced-ventilated trickling filter (TF) used as bioreactor. The effect of 8 different GLRs (1.2–15.7) on carbon dioxide removal and heat loss from water passing a trickling filter were tested in random order. The TF was part of a pilot scale fresh water intensive recirculating aquaculture system and had a media bed height of 1.8 m, a diameter of 0.9 m, a specific surface area of 200 m2/m3 and was operated at a fixed hydraulic surface load of 9.42 m3/m2.h, a mean inlet water temperature of 27.0–27.5 °C, and a mean inlet pH ranging from 7.02–7.12. For each GLR, CO2 removal from water was calculated from CO2 measurements in the inlet and outlet air of the TF using an online infrared probe (developed for agriculture and greenhouses) and from 12 water measurements done once every 3 h during 2 subsequent days. The water inlet CO2 concentrations varied between 4.5–9.0 mg/L (calculated from total inorganic carbon and pH). The results showed that the CO2 removal from water to the air in a trickling filter increased from 3.1 mg/L at a GLR of 1 to 6.1 mg/L for a GLR of 15. The relationship between GLR and CO2 removal could be described as an asymptotic curve with the following equation [Formula presented]; (R2 = 0.91). A linear relation between total heat loss across the TF and the applied GLRs showed an average total heat loss of 33.2 kJ per cubic meter of air for all GLRs. Of the total heat loss on average 91 % was latent heat loss and 9 % sensible heat loss. This study showed that: (1) GLRs above 5 will not result in significant additional CO2 removal; (2) energy loss at a GLR of 5 is, under our experimental conditions with a mean inlet air temperature of 22.6 °C and an mean inlet air relative humidity of 66.9 %, 26.0 kJ per g CO2 removed.

    Rodent-borne health risks in farming systems
    Krijger, Inge Milou - \ 2020
    Wageningen University. Promotor(en): P.W.G. Groot Koerkamp, co-promotor(en): B.G. Meerburg; S.R. Belmain. - Wageningen : Wageningen University - ISBN 9789463951890 - 197

    Rodents represent the largest order of mammals (>40%) and consist of over 2000 species. However, only a small portion (<10%) of all rodent species can be referred to as pest species. There is a knowledge gap on the biology and habitat specialisations and distribution of many rodent species in Asia and in Europe, which is essential for the species-specific management of pest rodents. The main aim of this thesis was to obtain more knowledge about rodent-borne health risks in farming systems in both Europe and Asia. The chapters of this thesis describe several studies into rodents from the Netherlands and Bangladesh in order to find an answer to the main research question of this thesis.

    In this thesis, for both countries rodent presence is demonstrated, as well of the presence of zoonotic pathogens in these animals. It can be concluded that there are serious rodent-borne health risks in farming systems in both in the Netherlands and in Bangladesh. The results of this thesis may help to improve the preparedness for potential disease outbreaks. It is essential to gain a more thorough understanding of the ecology of rodent-borne pathogens in rodents and humans in order to determine the public health risks associated with commensal rodents.

    Modelling the Reduction of Ammonia Emission of a Naturally Ventilated Cow House Using an Acidified Water Curtain
    Ooster, A. van 't; Melse, R.W. ; Bokma, S. ; Derks, M. ; Andela, Yeb ; Verstegen, Jeroen ; Groot Koerkamp, P.W.G. - \ 2019
    - p. 1 - 8.
    3D technology helps dairy farmers identify sick cows
    Song, Xiangyu ; Groot Koerkamp, Peter ; Bokkers, E.A.M. ; Tol, Rik van der - \ 2019

    Current precision livestock farming applications for managing dairy cow health are often slow in identifying diseases.

    The skin-deep beauty of dairy cows : Investigation of metabolic disorders by using morphological traits quantified with 3-Dimensional vision
    Song, Xiangyu - \ 2019
    Wageningen University. Promotor(en): P.W.G. Groot Koerkamp, co-promotor(en): E.A.M. Bokkers; P.P.J. van der Tol. - Wageningen : Wageningen University - ISBN 9789463950794 - 121

    Dairy farmers aim to produce high-quality products and meanwhile to ensure the health of their cows. To remain healthy, dairy cows need to eat well. If cows cannot have sufficient food and nutrients to support their daily lives, they could become sick and start changing their physical appearances, such as getting thinner. It is important for farmers to find sick cows as early as possible to offer timely treatment and to prevent further loss. Finding all the sick cows on farms manually based on their physical appearances , however, can cost farmers a great deal of time or money. With the goal of helping farmers, this dissertation has developed an automated system to monitor dairy cows’ physical appearance changes in the whole body and the rumen by using 3D cameras. The automated measurements were compared with expert assessments, and the differences were neglectable. Moreover, the 3D vision system has been applied on a commercial farm to regularly monitor individual cows for a period, where their feeding was changed from silage to fresh grass. Cows responded quickly to this feeding change, and these responses were successfully captured by the 3D vision system. This 3D vision system is automated, non-invasive, and animal-friendly and, hence, it has great potential to be widely used on commercial farms. The automatically measured physical appearances are not only the ‘skin-deep’ beauty of dairy cows but also essential indicators to help farmers in their daily health and feeding management to reach a high-quality production.

    Resilience of yak farming in Bhutan
    Dorji, Nedup ; Derks, M. ; Dorji, P. ; Groot Koerkamp, P.W.G. ; Bokkers, Eddie - \ 2019
    In: Book of abstracts of the 70th Annual Meeting of the European Federation of Animal Science. - Wageningen : Wageningen Academic Publishers (Book of abstracts 25) - ISBN 9789086863396 - p. 426 - 426.
    Hot topic: Automated assessment of reticulo-ruminal motility in dairy cows using 3-dimensional vision
    Song, X. ; Tol, P.P.J. van der; Groot Koerkamp, P.W.G. ; Bokkers, E.A.M. - \ 2019
    Journal of Dairy Science 102 (2019)10. - ISSN 0022-0302 - p. 9076 - 9081.
    3-dimensional camera - automatic - dairy cattle - ruminal motility

    Reticulo-ruminal motility is a well-established indicator of gastrointestinal health in dairy cows. The currently available methods for assessing motility are labor-intensive, costly, and impractical to use regularly for all cows on a farm. We hypothesized that the reticulo-ruminal motility of dairy cows could be assessed automatically and remotely using a low-cost 3-dimensional (3D) camera. In this study, a 3D vision system was constructed and mounted on the frame of an automatic milking robot to capture the left paralumbar fossa of 20 primiparous cows. For each cow, the system recorded 3D images at 30 frames per second during milking. Each image was automatically processed to locate the left paralumbar fossa region and quantify its average concavity. Then, the average concavity values from all images of 1 cow during 1 milking process were chronologically assembled to form an undulation signal. By applying fast Fourier transformation to the signal, we identified cyclic oscillations that occurred in the same frequency range as reticulo-ruminal contractions. To validate the oscillation identification, 2 trained assessors visually identified reticulo-ruminal contractions from the same 3D image recordings on screen. The matching sensitivity between the automatically identified oscillations and the manually identified reticulo-ruminal contractions was 0.97. This 3D vision system can automate the assessment of reticulo-ruminal motility in dairy cows. It is noninvasive and can be implemented on farms without distressing the cows. It is a promising tool for farmers, giving them regular information about the gastrointestinal health of individual cows and helping them in daily farm management.

    Rethinking livestock production systems on the Galápagos Islands: Organizing knowledge-practice interfaces through reflexive interactive design
    Puente-Rodríguez, Daniel ; Bos, Bram ; Groot Koerkamp, Peter W.G. - \ 2019
    Environmental Science & Policy 101 (2019). - ISSN 1462-9011 - p. 166 - 174.
    Galápagos Islands - Knowledge coproduction - Knowledge-practice interfaces - Livestock - Participatory methodologies - Reflexive interactive design

    Different economic interests and frames of meaning around livestock production and environmental management usually lead to controversies. This is also the case on the Galápagos Islands. The literature usually focusses on Galápagos’ ecosystems and wildlife. However, less attention is given to livestock production systems on the archipelago. In this article, we introduce an initiative to redesign the livestock (i.e., pigs and poultry) production systems on the Galápagos Islands to achieve a higher degree of socio-ecological sustainability by deploying the first phase of the ‘reflexive interactive design’ (RIO) approach. On the basis of an interactive system analysis, this article answers the following question: What redesign options can be coproduced, and how, to enable a change towards sustainable livestock production systems? To analyse this (re)design process this article deploys and further elaborates the concept of knowledge-practice interfaces.

    Behaviour and sociability of yaks among different regions in Bhutan
    Dorji, Nedup ; Groot Koerkamp, P.W.G. ; Derks, M. ; Bokkers, Eddie - \ 2019
    In: Animal lives worth living. - Wageningen Academic Publishers - ISBN 9789086863389 - p. 265 - 265.
    Prevalence of leptospira infection in rodents from Bangladesh
    Krijger, Inge M. ; Ahmed, Ahmed A.A. ; Goris, Marga G.A. ; Groot Koerkamp, Peter W.G. ; Meerburg, Bastiaan G. - \ 2019
    International Journal of Environmental Research and Public Health 16 (2019)12. - ISSN 1661-7827
    Food safety - Leptospirosis - Reservoir - Rodents - Zoonosis

    Worldwide, Leptospira infection poses an increasing public health problem. In 2008, leptospirosis was recognised as a re-emerging zoonosis of global importance with South-East Asia being one of the most significant centres of the disease. Rodents are thought to be the most important host for a variety of Leptospira serovars. Because Bangladesh offers a suitable humid climate for the survival of these pathogenic bacteria, the presence of rodents could be a serious risk for human infection, especially in peri-urban areas or locations where food is stored. In order to gain more understanding of the multi-host epidemiology, a prevalence study was conducted in Comilla, Bangladesh to determine the presence of pathogenic Leptospira species in rodents. Real-time Polymerase Chain Reaction (qPCR) and sequencing showed that 13.1% (61/465) of the trapped rodents were infected with pathogenic Leptospira. Sequencing of the qPCR products identified the presence of three species: Leptospira interrogans, Leptospira borgpetersenii, and Leptospira kirschneri. Rodents of the genus, Bandicota, were significantly more likely to be positive than those of the genus, Rattus and Mus. Our results confirm the importance of rodents as hosts of pathogenic Leptospira and indicate that human exposure to pathogenic Leptospira may be considerable, also in places where food (rice) is stored for longer times. This study emphasizes the need to improve rodent management at such locations and to further quantify the public health impacts of this neglected emerging zoonosis in Bangladesh.

    Automated body condition scoring of dairy cows using 3-dimensional feature extraction from multiple body regions
    Song, X. ; Bokkers, E.A.M. ; Mourik, S. van; Groot Koerkamp, P.W.G. ; Tol, P.P.J. van der - \ 2019
    Journal of Dairy Science 102 (2019)5. - ISSN 0022-0302 - p. 4294 - 4308.
    3-dimensioanl camera - automatic - body condition score - dairy cattle

    Machine vision technology has been used in automated body condition score (BCS) classification of dairy cows. The current vision-based classifications use information acquired from a limited number of body regions of the cow. Our study aimed to improve automated BCS classification by including multiple body condition–related features extracted from 3 viewpoints in 8 body regions. The data set of this study included 44 lactating cows with their BCS evenly distributed over the scale of BCS from 1.5 to 4.5 units. The body images of these cows were recorded over 2 consecutive days using 3-dimensional cameras positioned to view the cow from the top, right side, and rear. Each image was automatically processed to identify anatomical landmarks on the body surface. Around these anatomical landmarks, the bony prominences and body surface depressions were quantified to describe 8 body condition–related features. A manual BCS of each cow was independently assigned by 2 trained assessors using the same predefined protocol. With the extracted features as inputs and manual BCS as the reference, we built a nearest-neighbor classification model to classify BCS and obtained an overall classification sensitivity of 0.72 using a 10-fold cross-validation. We conclude that the sensitivity of automated BCS classification has been improved by expanding the selection of body condition–related features extracted from multiple body regions.

    Farming with Mathematical Precision
    Mourik, S. van; Groot Koerkamp, P.W.G. ; Henten, E.J. van - \ 2018
    ERCIM news 113 (2018). - ISSN 0926-4981
    A key challenge in precision farming is complex decision making under variable and uncertain circumstances. A possible solution is offered by mathematical models and algorithms.
    Towards a more sustainable way of nitrogen management in potatoes
    Booij, J.A. ; Evert, F.K. van; Geel, W.C.A. van; Kroonen-Backbier, B.M.A. ; Kempenaar, C. - \ 2018
    In: Book of Abstracts of the European Conference on Agricultural Engineering AgEng2018. - Wageningen : Wageningen University & Research - p. 112 - 112.
    Proceedings of the European Conference on Agricultural Engineering AgEng2018
    Groot Koerkamp, P.W.G. ; Lokhorst, C. ; Ipema, A.H. ; Kempenaar, C. ; Groenestein, C.M. ; Oostrum, Casper van; Ros, Nardy - \ 2018
    Wageningen : Wageningen University & Research - 1035 p.
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