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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Chain governance, sector policies and economic sustainability in cocoa; A comparative analysis of Ghana, Côte d'Ivoire, and Ecuador
Ton, G. ; Hagelaar, J.L.F. ; Laven, A. ; Vellema, S. - \ 2008
Wageningen : Wageningen International (Markets, chains and sustainable development 12) - ISBN 9789085854005 - 40
economische ontwikkeling - economisch beleid - overheidsbeleid - kettingen - cacao - economische analyse - ghana - ivoorkust - ecuador - duurzame ontwikkeling - economic development - economic policy - government policy - chains - cocoa - economic analysis - cote d'ivoire - sustainable development
Understanding institutional arrangements: Fresh Fruit and Vegetable value chains in East Africa
Eaton, D.J.F. ; Meijerink, G.W. ; Bijman, J. - \ 2008
Wageningen : Wageningen International (Markets, chains and sustainable development [11]) - ISBN 9789085852285 - 79
economische ontwikkeling - kettingen - fruitteelt - groenteteelt - oost-afrika - landbouwsector - ketenmanagement - institutionele economie - economic development - chains - fruit growing - vegetable growing - east africa - agricultural sector - supply chain management - institutional economics
Thai Dutch Partnership on safe fruit and vegetable supply chains
Stallen, M.P.K. ; Aalberts, C.H.J. - \ 2007
LEI
groenten - vruchten - aanbod - kettingen - thailand - voedselveiligheid - vegetables - fruits - supply - chains - food safety
Pamphlet about Thai Dutch Partnership on safe fruit and vegetable supply chains
Production chains as configurations for development : perspectives for innovation, market development and collaboration
Vellema, S. - \ 2006
Wageningen : Wageningen International (Internationa development discussion paper 2006-1) - 8
landbouwproductie - voedselproductie - kettingen - innovaties - markten - ontwikkeling - agricultural production - food production - chains - innovations - markets - development
Seeing chains for agricultural and food products as a possible instrument for development processes in the South opens up an important discussion about the institutional architecture of agricultural development. One of the major reasons for introducing marketled development schemes has been the growing pressure for downsizing government and public institutions over the past few decades. As a result, supply chains, entrepreneurs and networks between public and private parties have become more and more actively involved in development processes. At the same time, we have seen the international food trade being subjected to increasingly stringent standards by both public legislation and private demands. The fear that these kinds of regulations could exclude large groups of producers has given rise to a debate about the real implications of trade relations and chain formation. It also raises the question of how producers in the South can equip themselves to be in a strong position to take part in international trade and in international chains. It therefore seems important to reflect on the question of what sort of configuration chains really are, and what the options are for reconfiguring them. This article outlines a number of considerations
Soja handel- en ketenrelaties. Sojaketens in Brazilië, Argentinië en Nederland
Berkum, S. van; Roza, P. ; Pronk, A. - \ 2006
Den Haag : LEI (Rapport / LEI : Domein 5, Ketens ) - ISBN 9086150993 - 77
agrarische economie - kettingen - handel - internationale handel - sojabonen - nederland - argentinië - brazilië - ketenmanagement - agricultural economics - chains - trade - international trade - soyabeans - netherlands - argentina - brazil - supply chain management
Dit rapport beschrijft en analyseert de sojaketen in en handelsrelaties tussen Brazilië, Argentinië en Nederland. Naast de ontwikkelingen in de sojateelt sinds 1990 wordt ingegaan op de belangrijkste structuurkenmerken van de sojaketen in beide Latijns- Amerikaanse landen. Speciale aandacht wordt gegeven aan de relatie van de teelt met ontbossing, de rol van genetische modificatie en de economische perspectieven van de teelt in de komende jaren. De handelrelaties met Nederland worden uitgelicht en de relaties en belangrijke spelers in de sojaketen in Nederland in kaart gebracht. Hierdoor ontstaat een samenhangend beeld van de sojateelt en -handel, en de rol van Nederland daarbij.
Duurzaamheid in agrofood ketens
Kramer, K.J. ; Thors, M. ; Wolfert, J. - \ 2003
Den Haag : LEI Wageningen UR - 71
agrarische economie - kettingen - duurzaamheid (sustainability) - productie - nederland - agro-industriële ketens - maatschappelijk verantwoord ondernemen - agricultural economics - chains - sustainability - production - netherlands - agro-industrial chains - corporate social responsibility
Schakels : supply chain analyse kwaliteit, economie en logistiek in de voedingstuinbouw, de kleding en de cosmetica
Veerdonk, W.J.A.A. van de - \ 2000
Wageningen etc. : ATO [etc.] - 63
kettingen - economie - kwaliteit - kleding - tuinbouw - cosmetica - voedselindustrie - chains - economics - quality - clothing - horticulture - cosmetics - food industry
Salmonella in the pork production chain: Sources of Sal;monella on pork
Swanenburg, M. - \ 2000
- 159
varkens - varkenshouderij - salmonella - varkensvlees - voedselvoorziening - kettingen - bacteriologie - besmetting - hygiëne - slachthuizen - nederland - pigs - pig farming - pigmeat - food supply - chains - bacteriology - contamination - hygiene - abattoirs - netherlands
Effective food supply chains : generating, modelling and evaluating supply chain scenarios
Vorst, J.G.A.J. van der - \ 2000
Agricultural University. Promotor(en): Adrie Beulens. - S.l. : S.n. - ISBN 9789058082619 - 305
bedrijven - voedselvoorziening - kettingen - marktconcurrentie - distributie - simulatie - voedingsmiddelen - bedrijfsvoering - wiskundige modellen - ketenmanagement - logistiek - businesses - management - food supply - chains - foods - distribution - market competition - mathematical models - simulation - supply chain management - logistics
<h3>Logistical co-ordination in FMCG supply chains</h3><p>The overall objectives of the research described in this thesis were to obtain insight into the applicability of the concept Supply Chain Management (SCM) in food supply chains (SCs) from a logistical point of view, and to find an efficient and effective method to analyse and redesign the SC to improve SC performance.</p><h4>Background</h4><p>The background and rationale of this thesis are discussed in Chapter 1. Interest in SCM has been spurred by recent socio-economic developments. Because of demographic and socio-economic developments (e.g. strong increase of the ageing population, more double-income families) there is a growing demand for fresher products and products with higher added values. Furthermore, the effects of globalisation, the market entrance of new competitors, and stricter governmental requirements for food safety and environment-friendly production place increasing demands on management. These developments have resulted in a change in performance requirements for food SCs as a whole and, consequently, for all stages in the SC. Managers realised that sub-optimisation occurs if each organisation in a SC attempts to optimise its own results rather than to integrate its goals and activities with other organisations to optimise the results of the entire chain. This holds true especially in food SCs where particular actors in the SC can damage all the efforts taken in another stage to preserve high product quality. There has been growing recognition that it is through logistics and SCM that the twin goals of cost reduction and service enhancement can be achieved. The recent developments in Information and Communication Technology facilitate this process.</p><h4>Research objective and questions</h4><p>The main questions food companies face are <em>whether</em> , <em>how,</em> and <em>with whom</em> they should start SCM activities. They should be able to analyse what SCM can do for them and find out what the consequences might be if a SC view is taken together with one or more supplier(s) and/or customer(s). An extensive literature research did not reveal any integral method to generate, analyse and evaluate SC redesigns, i.e. SC scenarios (Chapters 2 and 4). Our <em>research objective</em> was therefore to contribute to the body of knowledge on SCM by developing a step-by-step approach that could generate, model and evaluate SC scenarios in specific food SCs. That is, we aimed to develop:</p><ol><li>a research method to analyse a food SC and to generate a number of SC scenarios that are estimated to improve the current SC performance;</li><li>a research method to assess the impact of different SC scenarios for a particular food SC on SC performance and to identify a 'best practice' SC scenario.</li></ol><p>A 'best practice' SC scenario refers to a feasible SC scenario that achieves the best possible outcome for the whole system with respect to predefined SC performance indicators. Both methods should assist managers of food companies in evaluating their current position in a food SC and in deciding whether and how they should redesign the SC.</p><p>In Chapter 1 we developed a <em>proposition</em> to guide our research. Because of rapid changes in markets, products, technology, and competitors, managers must make decisions on shorter notice, with less information, and with higher penalty costs than in the past. Decision making uncertainty has increased regarding what developments managers should react to and what impact possible actions may have. By breaking down the walls that are present between successive SC stages, decision making uncertainties may decline, since more information and control possibilities will become available to the decision-makers in each stage. This led us to the following proposition: <em>To identify effective SC scenarios one should focus on the identification and management of the sources of uncertainties in SC decision making processes.</em></p><p>On the basis of this proposition the following three <em>research questions</em> were formulated:</p><ol><li>What is the relationship between uncertainty in SC decision making processes and SC performance in food SCs?</li><li>How can we identify potentially effective SC scenarios for a particular food SC? (validation of the proposition)</li><li>How can SC scenarios be assessed with regard to SC performance and the individual performance of the SC participants?</li></ol><h4>Research design</h4><p>Considering the research objectives and type of research questions to be answered, we used the multiple-embedded case study design. This research followed the inductive/deductive research cycle, in which literature and case studies were used to devise a research method on the generation, modelling and evaluation of SC scenarios. Three case studies were selected. Case I was conducted in a fresh food SC, comprising growers, auctions, an exporter of vegetables and fruits, and foreign retailers. Case II comprised a salad producer and a retail organisation (made up of a retail distribution centre and retail outlets). Finally, case III comprised two suppliers of desserts, a cheese producer and a retail organisation. We used the chosen case studies in two ways:</p><ul><li>All three exploratory case studies were used for theory building, addressing (1) the relationship between uncertainty and performance and (2) the identification of potentially effective SC scenarios.</li><li>The two latter case studies were further elaborated upon to explore the area of (3) assessing the impact of SC scenarios on SC performance, in order to identify a 'best practice' SC scenario for that particular food SC.</li></ul><h4>Main definitions</h4><p>Chapter 2 showed that there is no generally accepted definition of a SC and SCM. The dispute mainly focuses on the level of analysis. Based on the findings in literature, we defined a supply chain as the series of (physical and decision making) activities connected by material and information flows that cross organisational boundaries. SCM was defined as follows:</p><p><em>Supply Chain Management is the integrated planning, co-ordination and control of all logistical business processes and activities in the SC to deliver superior consumer value at less cost to the SC as a whole whilst satisfying the requirements of other stakeholders in the SC.</em></p><p>Our system and process view on SCs was presented in Chapter 3, resulting in a definition of a SC scenario:</p><p><em>A SC scenario is an internally consistent view of the settings of all SC redesign variables concerning the managed, managing, and information systems and organisation structure in the SC.</em></p><p>The four descriptive system elements comprising a SC scenario were described in detail in Chapter 3. A <em>SC redesign variable</em> is defined as a management decision variable at strategic, tactical or operational level that determines the setting of one aspect of the SC configuration or management and control. Furthermore, we identified <em>Key Performance Indicators</em> (KPIs) for food SCs that are needed to assess the effectiveness of SC scenarios, i.e. the degree to which the SC objectives are fulfilled. Finally, Chapter 3 concluded with a conceptual model that can be used to describe, analyse and typify a SC in detail to facilitate the SC redesign process.</p><h4>Approach for SC analysis and redesign</h4><p>In Chapter 4 we developed a preliminary research method for generating potentially effective SC scenarios. First, a review of literature in several areas (SCM, Logistics Management, Business Process Re-engineering and Operational Research) led us to a generic list of 22 SCM redesign principles that are thought to be able to improve performance on one or more SC KPIs. Each redesign principle refers to alternative settings for one or more of the SC redesign variables, thereby representing various SC scenarios. Second, by linking the list of redesign principles to potential sources of SC uncertainty in a SC, we found a means of identifying potentially effective SC redesign variables for that SC. Those sources of SC uncertainty that impact the SC KPIs are the first candidates for the redesign process. This approach was tested and further elaborated in Chapter 5, in which we discussed the findings of three exploratory case studies.</p><p>We concluded that sources of SC uncertainty refer to inherent characteristics of the SC and characteristics of the managed system, managing system, information system and/or organisation structure that are present at a certain point in time and that generate SC uncertainty. Our definition of SC uncertainty is based on the general requirements for effective control presented by De Leeuw (1988):</p><p><em>SC uncertainty refers to decision making situations in the SC in which the decision-maker lacks effective control actions or is unable to accurately predict the impact of possible control actions on system behaviour because of a lack of:</em></p><ul><li>information (or understanding) of the environment or current SC state;</li><li>a consistent model of the SC presenting the relationships between SC redesign variables and SC performance indicators.</li></ul><h4>Generating SC scenarios in food supply chains</h4><p>By applying the framework for SC analysis and redesign developed in Chapter 3 to the three case studies (Chapter 5), a detailed picture emerged of the configuration and operational control of activities in the SC. In this process, Organisation Description Language (ODL) and Event Process Chain (EPC) mapping techniques provided a powerful basis to redesign the SC, because it made the total process transparent and it made it possible for us to illustrate the opportunities for eliminating non-value-adding processes to managers. These techniques facilitated discussions with key employees in the SC and helped in identifying SC uncertainties and, more important, sources of SC uncertainty.</p><p>In all three cases the identification of SC uncertainties and especially their sources led to the recognition of potentially effective SC redesign variables. In this process the generic list of SCM redesign principles helped in identifying a complete overview of possible SC redesign strategies. By estimating the impact of each strategy on the SC KPIs, potentially effective SC redesign variables were identified.</p><p>In all three case studies an extended list of sources of SC uncertainty was identified. This allowed us to create a generic list of sources of SC uncertainty that may be found in food SCs. By linking this list to the generic list of SCM redesign principles developed in Chapter 4, we generated a valuable tool for SC redesign projects. It lists potential improvement areas in the SC when certain types of SC uncertainty are encountered in an investigated SC.</p><h4>Modelling and evaluating SC scenarios</h4><p>After SC scenarios are identified, we need an approach to model and evaluate these scenarios to determine the best practice SC scenario. In Chapter 6 we concluded that the combination of two methods is most effective:</p><ul><li>First, a <em>mathematical model</em> of the SC has to be built that allows for the quantitative assessment of the impact of SC scenarios on the SC KPIs. Because of multiple performance- and time-related process aspects that need to be taken into account when modelling SCs we focussed in our research on simulation instead of analytical modelling.</li><li>Second, a <em>field test experiment</em> has to be conducted in the SC comprising one of the most promising SC scenarios, to provide practical and organisational restrictions and to thus reveal the feasibility of alternative SC designs.</li></ul><p>In Chapter 6 we also developed a modelling framework for modelling the dynamic behaviour of food SCs. We believe the modelling framework captures all relevant concepts of the SC system needed to adequately model and simulate SC scenarios. The main modelling components are business processes, business entities, databases, resources, performance indicators and redesign variables. To model the dynamic behaviour of SCs some general assumptions are used as a starting point. For example, we assume system hierarchy, and we view the SC as a network of business processes with precedence relationships that use resources, and as a dynamic system with changing performance characteristics (especially when the time frames considered change). Two simulation tools, ExSpect and Arena, are introduced that were used in the two case studies in Chapter 7 for evaluating SC scenarios.</p><p>The case studies showed the applicability of the modelling approach. Simulation results, validated by managers of the participating companies (expert validation), showed the trends and order of magnitude of changes in SC performances of different SC scenarios. Both ExSpect and Arena proved to be promising tools for modelling SC scenarios, although each of them had some disadvantages.</p><p>The case studies also showed the complementarity of the field test to a simulation study; in one case study the best performing scenario in the simulation study was exchanged for a feasible scenario Y because of the field test results. By using this evaluation approach, SC managers can be supported in deciding whether or not to implement a new SC scenario. In both case studies, SC scenarios were suggested that perform considerably better than the current design.</p><p>Finally, an analytical approach was suggested for model validation purposes. It showed that analytical models can be used very successfully for smaller SC problems.</p><h4>A step-by-step approach to generate, model and evaluate supply chain scenarios</h4><p>Chapter 8 summarised our complete step-by-step approach for the analysis and redesign of food SCs which aims at identifying a best practice SC scenario for a particular food SC (Figure 1).</p><p>The approach starts with the joint definition of the boundaries of the SC to be investigated and the SC objectives ( <em>step 1</em> ). From these objectives the SC KPIs are identified. By describing the SC processes in detail SC uncertainties and their sources are identified ( <em>step 2</em> ). Effective SC scenarios are identified by linking the main sources of uncertainty found in the SC ( <em>step 3</em> ) with the list of SCM redesign principles ( <em>step 4</em> ). The potential SC scenarios are evaluated quantitatively and qualitatively by, respectively, a model study ( <em>step 5</em> ) and a field test experiment ( <em>step 6</em> ). Finally, a 'best practice' scenario can be identified and implemented in practice ( <em>step 7</em> ).</p><div align="center"><img src="/wda/abstracts/i2841.gif" width="550" height="440" alt="Figure 1." border="0"/><br/>Figure 1. A step-by-step approach to generate, model and evaluate SC scenarios.</div><h4>Main conclusions</h4><p>Finally, Chapter 9 summarised the main findings and answered the three research questions as follows:</p><ol><li><em>What is the relationship between uncertainty in SC decision making processes and the SC performance in food SCs?</em><p>The presence of uncertainties in SC decision making situations results in the establishment of safety buffers in time, capacity and/or inventory to prevent a poor SC performance. These safety buffers initiate the existence of several non-value-adding activities that reduce the profitability of the SC. Reducing or even eliminating the SC uncertainties will improve SC performance.</p></li><li><em>How can we identify potentially effective SC scenarios for a particular food SC?</em><p>The use of our step-by-step approach for generating effective SC scenarios will result in a number of important SC redesign variables. The combination of different settings for these SC redesign variables establishes a number of potentially effective SC scenarios. The degree of effectiveness has to be determined in the evaluation phase (research question 3).</p></li><li><em>How can SC scenarios be assessed with regard to SC performance and the individual performance of the SC participants?</em><p>The impact of a SC scenario on SC performance should preferably be evaluated by using both a modelling (simulation) study and a field test experiment. In this way the new SC scenario is evaluated both qualitatively (i.e. considering the behavioural and organisational aspects) and quantitatively. The modelling framework developed in this research provides a good means for capturing the dynamic behaviour of a food SC. The final decision of which SC scenario to implement depends on the trade-off between multiple SC performance indicators for each SC participant and the SC as a whole, and the feasibility of each SC scenario.</p></li></ol><p>We are confident that we have been successful in contributing to the body of knowledge on SCM. Our step-by-step approach (including the suggested tools and techniques) can be used to analyse, redesign and evaluate food SCs more effectively and efficiently, which enhances the competitive advantage of the SCs. It enables managers to assess the impact of SC scenarios on SC performance; it provides insight into SC functioning; and it works as a facilitator to allow managers to rethink current SC business processes.</p><h4>Opportunities for further research</h4><p>In our view SCM research should focus on the construction of a toolbox comprising theories, methods and techniques, and working applications to analyse and improve the management of the SC. We acknowledge that our step-by-step approach to generate, model and evaluate SC scenarios should be considered as a first step towards a generic toolbox that can be used to improve SC performances. This thesis concluded by suggesting some interesting areas for further research. The most important, in no particular order, are the following:</p><ul><li>Refinement of the lists of SCM redesign principles and sources of SC uncertainty (by reviewing other literature and doing case studies in other industries).</li><li>Adoption of a SC network perspective within SCM research emphasising the investigation of SC interactions.</li><li>Definition of unique and integrated SC performance measures.</li><li>Further research into the applicability of different types of quantitative methods combined with a typology of SC decision situations.</li><li>Elaboration and refinement of the SC modelling framework and the construction of a library of generic building blocks on the level of individual business processes to facilitate efficient and effective modelling of SCs.</li><li>The construction of a Decision Support System for SC analysis and redesign, using our step-by-step approach and the case study results, which generates SC scenarios automatically.</li><li>Incorporation of requirements of other stakeholders in the SC analysis, such as the government, environmental protection groups, and trade-unions.</li></ul>
New methods for feasibility studies on establishment of new agricultural production chains
Meeusen-Van Onna, M.J.G. - \ 1998
Den Haag : LEI-DLO (Mededeling / Agricultural Economics Research Institute (LEI-DLO) 627) - ISBN 9789052424651 - 48
landbouwproductie - kettingen - ruwe grondstoffen - verpakkingsmaterialen - economische analyse - methodologie - aanbod - bedrijfsvoering - ? - agricultural production - chains - raw materials - packaging materials - economic analysis - methodology - supply - management
Jonge Swifter ooien voor dekken scheren geeft hogere drachtigheid
Boer, J. de - \ 1994
Praktijkonderzoek / Praktijkonderzoek Rundvee, Schapen en Paarden (PR), Waiboerhoeve 7 (1994)4. - ISSN 0921-8874 - p. 25 - 27.
dierhouderij - veredelingsmethoden - tussenkalftijd - kettingen - embryotransplantatie - ooien - eiceltransplantatie - zwangerschap - productiviteit - rentabiliteit - vastleggen - animal husbandry - breeding methods - calving interval - chains - embryo transfer - ewes - ova transfer - pregnancy - productivity - profitability - tethering
De conclusie was dat de drachtigheid bij de jonge Swifter ooien toenam met 14% bij scheren voor het dekken. Bij Texelaars zijn dergelijke resultaten niet gevonden.
Wel of niet aanbinden van zeugen in het kraamopfokhok
Bokma, Sj. - \ 1989
Rosmalen : Proefstation voor de Varkenshouderij (Proefverslag / Proefstation voor de Varkenshouderij P1.38) - 24
kettingen - kraamstallen - varkens - zeugen - vastleggen - chains - farrowing houses - pigs - sows - tethering
Zeugen niet voor het eerst aanbinden in kraamstal
Bokma, Sj. - \ 1989
Praktijkonderzoek varkenshouderij 3 (1989)1. - ISSN 1382-0346 - p. 9 - 11.
kettingen - zeugen - vastleggen - chains - sows - tethering
Zeugen, die in de kraamstal voor het eerst worden aangebonden werpen biggen die gemiddeld 50 gram lichter zijn.
Loslopende zeug in kraamhok geeft nog problemen
Plagge, G.J. ; Havermans, M.U.C. - \ 1988
Praktijkonderzoek varkenshouderij 2 (1988)5. - ISSN 1382-0346 - p. 4 - 5.
kettingen - kraamstallen - varkens - zeugen - vastleggen - chains - farrowing houses - pigs - sows - tethering
Op het Varkensproefbedrijf te Raalte loopt sinds 1987 een vergelijkend onderzoek naar kraamopfokhokken. Uit de voorlopige cijfers blijkt, dat de systemen met de zeug in de box als beste uit de bus komen.
Vastzetsystemen in grupstallen = Self-catching systems and related aspects of tying cowhouses
Westendorp, T. - \ 1987
Wageningen : IMAG (Publikatie / Instituut voor Mechanisatie, Arbeid en Gebouwen 219) - 44
kettingen - stallen - tuierhuisvesting - vastleggen - chains - stalls - tethered housing - tethering
Toen in november 1978 op de Waiboerhoeve te Lelystad een nieuwe grupstal voor onderzoeksdoeleinden gereed kwam, werd ook gedacht aan beproevingen van, al of niet geautomatiseerde, vastzetsystemen. Naast vastzetsystemen, en in samenhang daarmee, kwamen bij dit onderzoek zaken als standafmetingen en standbedekking aan de orde. In deze publikatie wordt op deze aspecten van de stalinrichting nader ingegaan. Voorafgaande aan de onderzoeksresultaten wordt verder nog aandacht geschonken aan de enkele andere belangrijke aspecten van de grupstal, die in de literatuur zijn vermeld
The development and significance of abnormal stereotyped behaviours in tethered sows
Cronin, G.M. - \ 1985
Landbouwhogeschool Wageningen. Promotor(en): P.R. Wiepkema, co-promotor(en): J.M. van Ree. - Wageningen : Cronin - 146
zeugen - vastleggen - kettingen - diergedrag - sows - tethering - chains - animal behaviour
<p/>The development and performance of abnormal stereotyped behaviours (stereotypies) by tethered sows were studied in order to investigate the consequences of the behaviours for animal welfare and sow productivity.<p/>In Chapter 2, the behaviour of 36 tethered sows in a commercial herd was analysed to determine the characteristics of stereotypies, and to enable their definition. The proportion of observation time that sows performed stereotypies was related to the stage of pregnancy, i.e. the time spent tethered in the current parity. Sows increased the proportion of time spent stereotyping between 10.00-14.00 h up to day 80 of pregnancy, after which stereotyping decreased.<p/>Chapter 3 describes the process of development of stereotypies in sows after tethering. Sows were initially very vigorous and aggressive in their response to tethering. Stereotypies eventually developed after the sows had passed through a number of distinct stages, termed 1) escape attempt, 2) inactivity, 3) outwarddirected activity and 4) basic stereotypy stages. The median durations (and ranges) of the first 3 stages were 45 min (10 to 180 min), 1 day (140 min to 16 days) and 15.7 days (7.8 to 55 days), respectively. Once a basic stereotypy was developed, random aggressive-like acts were rarely observed. The stereotypies that developed in response to tethering contained components that were directed at features in the sows' external environment (e.g. chains, drinker, bars, etc.), and were in part derived from redirected aggressive acts. Over time, the level of aggression declined and the actions were "rounded off". In stage 4, sows built larger stereotypies through the addition of new elements, although they could always revert to the performance of just the basic components.<p/>It was concluded that environment-directed stereotypies develop as a result of frustration/conflict at being restrained, and the consequent loss of controllability over the environment.<p/>An hypothesis was proposed which implicated endorphins (endogenous opiates) in the development and performance of stereotypies by tethered sows. Evidence to support this hypothesis is presented in Chapter 4. Eight tethered and 3 loose-housed sows were treated with saline and the specific opioid antagonist naloxone on consecutive days. The tethered and loose sows were treated while they performed stereotypies and exploratory behaviours, respectively.<br/>Stereotypy performance levels were reduced in the 2 h following naloxone (median = 33% of the time) compared with saline (86%), but there was no effect on the performance of exploratory behaviour by loose sows. Many of the behaviours performed by the tethered sows after naloxone treatment were similar to behaviours performed by sows in response to initial tethering. Seven of the 8 tethered sows ceased the performance of their stereotypies in the short-term following naloxone. The latency to cease performance was positively related to the "age" of the particular stereotypy.<p/>The results strongly suggest that endorphins may be the factor underlying the development and performance of stereotypies. Endorphins are released in response to stress, and in time, sows may learn to self-stimulate the release through the performance of stereotypies. Stereotypies probably function to reduce the perception of the negative aspects of the real environment, over which tethered sows have no control, and "rebuild" a new and possibly much reduced environment that they control through the performance of stereotypies. The results suggest that sows perceive tethering in a very negative way.<p/>In Chapters 2, 3 and 4, it is reported that the stereotypies of tethered sows contain a certain amount of variability. For example, sows could vary the duration of stereotyped components between cycles of the stereotypy, or even omit components, and so on. Thus stereotypies were found to be considerably more variable than indicated by the classic definition of these behaviours.<p/>It is suggested in Chapter 7 that this variability may be an indication that the sow had not adapted to the stress of tethering. The continued perception of negative aspects in the environment may stimulate the release of endorphins, but also introduces variability into the performance of stereotypies.<p/>Stereotypies are behavioural indicators of past or current poor welfare status, a phenomenon which may be quantifiable via measurement of the degree of variability in stereotypy performance.<p/>Since stereotypies develop out of chronic stress situations, and since it has been reported that chronic stress influences the productivity of pigs, it was expected then that the performance of stereotypies may have consequences for sow productivity.<p/>In Chapter 5, tethered sows in a commercial herd were categorized according to the proportion of observation time between 10.00 and 14.00 h that they performed stereotypies. Within parity x pregnancy stage classes, non-lactating sows were classed as either HIGH or LOW stereotypers if they performed more or less than the mean level. At the farrowing prior to observation, HIGH stereotypers produced larger litters in parities 2 and 3, but smaller litters in parities 5 and 6, than LOW stereotypers. At the farrowing after observation, HIGH stereotypers tended to produce smaller litters in parities 5 and 6 than LOW stereotypers. Low parity number sows were less stable than older sows, in that more than half of the younger sows observed in successive parities changed stereotypy performance class between observations. Hence, the effects of stereotypy performance level on litter size of low parity number sows at the farrowing after observation were not consistent with those from the farrowing before observation.<p/>Contrary to expectation, the LOW stereotypers also tended to be less reactive to novel stimuli than HIGH stereotypers, suggesting that the former sows were "less normal" than the latter. The results further suggest that sows may be subject to chronic stress for at least 2 to 3 parities before adapting to tether housing. Young sows that were able to develop a stereotypy more rapidly (i.e. HIGH stereotypers), coped better in the short-term than LOW (non-coping) stereotypers.<p/>In Chapter 6, the metabolic rate and behaviour of sows were measured. The 2 treatments of sows had different degrees of adaptation to tethering. The experienced tethered sows were active stereotypers (HIGH sows) and the inexperienced tethered sows (T/LOW) were relatively inactive at the time of the experiment. The latter sows were released into a group (G/LOW) half-way through the experiment, for a comparison of tethered versus loose-housed sows.<p/>HIGH sows were about 3 times more active than T/LOW sows, due mostly to high stereotypy performance levels amongst the former sows. HIGH sows produced 35.7% more heat than the T/LOW sows during the 12 h light period of the day. During this period, 40.2% and 20.1% of heat production from HIGH and T/LOW sows was associated with activity. In comparison, G/LOW sows were slightly more active than T/LOW sows, with 23.5% of heat production being associated with activity.<p/>Stereotypy behaviour and excessive drinker manipulation by the HIGH, T/LOW and G/LOW sows accounted for 86, 52 and 24% of activity. The proportion of metabolizable energy intake required for these activities were 23, 7 and 4%, respectively, for sows in the 3 treatments. The results of the experiment indicate that tethering is stressful because of the need for sows to develop and perform large quantities of "coping behaviours% and the association with increased metabolic rate. It was also suggested that during the experiment, the T/LOW sows were following a path of adaptation to tether housing similar to that experienced earlier by the HIGH sows.<p/>Thus it is apparent that there is a positive association between welfare status and productivity of sows. Improvements in the welfare status of non-lactating sows will result in improved sow productivity. In the situation of the commercial environment, improvements to welfare status can only occur through improvements in the quality of the environment, for example by the removal of chronic stressors such as restraint.
Mededeling betreffende de hangketting met halsbeugel model 9020 van L.S. Brouwers N.V., Marshallweg 3 te Leeuwarden
Anonymous, - \ 1958
Wageningen : [s.n.] (Mededeling / Instituut voor landbouwbedrijfsgebouwen no. 2) - 3
rundvee - stallen - vastleggen - kettingen - cattle - stalls - tethering - chains
Mededeling betreffende de nylonhangriem van De Boer's borstelfabriek, Westerplantage 1 - 7 te Leeuwarden
Anonymous, - \ 1958
Wageningen : [s.n.] (Mededeling / Instituut voor landbouwbedrijfsgebouwen no. 1) - 3
rundvee - stallen - vastleggen - kettingen - cattle - stalls - tethering - chains
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