Completed PhD theses

2016

H.H.E. van Zanten: Feed sources for livestock: Recycling towards a green planet

On Friday 17 June 2016, at 13.30h Hannah van Zanten will defend her thesis entitled: Feed sources for livestock: Recycling towards a green planet.

View the ceremony via WUR-TV aula. The full text of the PhD-thesis is under embargo until July.

Promotor:

Prof. dr. M.N.C. Aarts, Strategic Communication Group

Co-promotors:

Prof. dr. ir. A.J. van der Zijpp, Animal Production Systems Group

Dr. G.A. Mensah, National Institute of Agricultural Research of Benin,

Abomey-Calavi, Benin

Prof. dr. C.R. Tossou, University of Abomey-Calavi, Benin

E.A. Groen: An uncertain climate: the value of uncertainty and sensitivity analysis in environmental impact assessment of food

On Tuesday 10 May 2016 Evelyne Groen has defended her thesis entitled: An uncertain climate: the value of uncertainty and sensitivity analysis in environmental impact assessment of food.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is under embargo until June 2017.

Promotor:

Prof. dr. ir. I.J.M. de Boer, Animal Production Systems Group

Co-promotors:

Dr. ir. E.A.M. Bokkers, Animal Production Systems Group

Dr. R. Heijungs, Department of Econometrics and Operations Research, VU University Amsterdam

Abstract:

Production of food contributes to climate change and other forms of environmental impact. Input data used in environmental impact assessment models, such as life cycle assessment (LCA) and nutrient balance (NB) analysis, may vary due to seasonal changes, geographical conditions or socio-economic factors (i.e natural variability). Moreover, input data may be uncertain, due to measurement errors and observational errors that exist around modelling of emissions and technical parameters (i.e. epistemic uncertainty). Although agricultural activities required for food production are prone to natural variability and epistemic uncertainty, very few case studies in LCA and NB analysis made a thorough examination of the effects of variability and uncertainty. This thesis aimed to enhance understanding the effects of variability and uncertainty on the results, by means of uncertainty and sensitivity analysis. Uncertainty analysis refers to the estimation of the uncertainty attribute of a model output using the uncertainty attributes of the model inputs.
There are three types of sensitivity analyses: (I) a local sensitivity analysis addresses what happens to the output when input parameters are changed, i.e. the intrinsic model behaviour of a parameter; (II) a screening analysis addresses what happens to the output based on the uncertainty range of the different input parameters; and (III) a global sensitivity analysis addresses how much the uncertainty around each input parameter contributes to the output variance. Both the screening analysis and the global sensitivity analysis combine the intrinsic model behaviour with the information of uncertainty around input parameters. Applying uncertainty analysis and sensitivity analysis can help to reduce the efforts for data collection, support the development of mitigation strategies and improve overall reliability, leading to more informed decision making in environmental impact assessment models.

Including uncertainty in environmental impact assessment models showed that: (1) the type of uncertainty analysis or sensitivity analysis applied depends on the question to be addressed and the available information; (2) in some cases it is no longer possible to benchmark environmental performance if epistemic uncertainty is included; (3) including correlations between input parameters during uncertainty propagation will either increase or decrease output variance, which can be predicted beforehand; (4) under specific characteristics of the input parameters, ignoring correlation has a minimal effect on the model outcome. Systematically combining a local and global sensitivity analysis in environmental impact assessment models: (1) resulted in more parameters than found previously in similar studies (for the case studies discussed in this thesis); (2) allowed finding mitigation options, either based on innovations (derived from the local sensitivity analysis) or on management strategies (derived from the global sensitivity analysis); (3) showed for which parameters reliability should be improved by increasing data quality; (4) showed that reducing the (epistemic) uncertainty of the most important parameters can affect the comparison of the environmental performance.

2015

G.N. Kpéra: Understanding complexity in managing agro-pastoral dams ecosystem services in Northern Benin

On Monday 2 November 2015 Gnanki Nathalie Kpéra has defended her thesis entitled: Understanding complexity in managing agro-pastoral dams ecosystem services in Northern Benin.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. M.N.C. Aarts, Strategic Communication Group

Co-promotors:

Prof. dr. ir. A.J. van der Zijpp, Animal Production Systems Group

Dr. G.A. Mensah, National Institute of Agricultural Research of Benin,

Abomey-Calavi, Benin

Prof. dr. C.R. Tossou, University of Abomey-Calavi, Benin

Abstract:

Agro-pastoral dams (APDs) – water reservoirs constructed to provide water for livestock and for agricultural development – have been constructed all over Benin. These APDs face several conflicts (farmers versus herders, council versus vegetable producers, fishermen versus council, and fishermen and APD users versus crocodiles) rooted in the multi-functionality of APDs and the involvement of diverse stakeholders. Using the integral ecology framework as the conceptual inspiration, the research gained insights on: (i) the complexity of APDs that impedes agreement on common rules for their management, (ii) the way stakeholders frame the presence of crocodiles, (iii) the health status of the APD ecosystem by using water quality, fish diversity, and fish biomass as indicators, (iv) the constraints that hinder vegetable production around the APDs. The study suggests that an innovation platform should be established in which all the stakeholders can discuss changes, resulting in optimal use of APD ecosystem services and their management.

T.S.M. Widi: Mapping the impact of crossbreeding in smallholder cattle systems in Indonesia

On Monday 29 June 2015 Tri Satya Mastuti Widi has defended her thesis entitled: Mapping the impact of crossbreeding in smallholder cattle systems in Indonesia.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. A.J. van der Zijpp, Animal Production Systems Group

Co-promotors:

Dr. ir. H.M.J. Udo, Animal Production Systems Group

Dr. ir. J.K. Oldenbroek, Centre for Genetic Resources

Abstract:

This study evaluates the benefits and consequences of crossbreeding with European beef breeds in smallholder cattle farming systems in Indonesia. The dualism in crossbreeding is that policy makers promote crossbreeding to meet the increasing demand for beef, whereas farmers are concerned with their livelihoods and the multi-functionality of cattle. In Madura, crossbreeding is not a threat to the two cultural events involving Madura cattle, sonok (cow conformation contest) and karapan (bull racing), nor to the sub-populations of Madura cattle in the specific areas where these events are organised. Farmers outside these areas prefer Limousin crossbreds to Madura cattle. In Java, crossbreeding (Simmental x local Ongole) does not change cattle farming systems. Crossbreeding is also not reducing rural poverty. Crossbreeding as a tool of intensification did not reduce the carbon footprint and land use per kilogram liveweight produced. Crossbreeding will continue in Java and Madura, however breeding strategies have to be adjusted. Viable populations of local cattle are needed to ensure sustainable crossbreeding strategies.

E.G. Kebebe: Understanding factors affecting technology adoption in smallholder livestock production systems in Ethiopia. The role of farm resources and the enabling environment

On Thursday 18 June 2015 Kebebe Ergano Gunte has defended his thesis entitled: Understanding factors affecting technology adoption in smallholder livestock production systems in Ethiopia. The role of farm resources and the enabling environment.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. I.J.M. de Boer, Animal Production Systems Group

Co-promotors:

Dr. ir. S.J. Oosting, Animal Production Systems Group

Dr. A. Duncan, International Livestock Research Institute, Addis Ababa, Ethiopia

Abstract:

In response to population growth, rising income and urbanisation, the demand for livestock products, such as milk, meat and eggs is growing in Ethiopia. The growing demand for milk products offers opportunities for smallholders to realize better livelihoods. Whereas the growing demand for milk products in Ethiopia is widely recognised, the dairy sector has not been able to produce adequate milk to satisfy this demand, mainly due to low productivity of dairy animals. The use of technological inputs, such as improved breeds of dairy cows and cultivation of improved forages, is often seen as a prerequisite to increasing livestock productivity and resource use efficiency in the smallholder dairy sector. However, adoption of such technologies has been low, despite numerous efforts to disseminate the technologies in the past. This poses a question as to why the majority of smallholders have not adopted livestock technologies in the Ethiopian highlands. The overall objective of this study was understanding the factors affecting adoption of technologies that enhance the productivity of livestock production and water use efficiency in the Ethiopian highlands, with particular emphasis on dairy production. The study was intended to deepen the understanding on the role of factors at the levels of farm households, value chains and macroeconomic institutions and policies on farmers’ decision to adopt technologies. The study employed interdisciplinary approach to analyse micro and macro level constraints that affect adoption of technologies in livestock production. The findings in the empirical chapters show that low adoption of the technologies that enhance the productivity of livestock production and water use efficiency stem from farmers’ limited access to farm resources, differentials in potential welfare impacts of the technologies, lack of effective and reliable supply chains for inputs and outputs, inadequate physical infrastructure and weak institutions and policies. The findings show that smallholders have been subjected to multiple constraints. Given the multiple constraints at different scales and the associated transaction costs facing smallholders in rural Ethiopia, the returns to investment for the technologies may be too low to justify widespread adoption of the technologies. Therefore, adoption of technologies in the dairy sector requires interventions at production, storage, transportation, processing and marketing chains and at macroeconomic institutions and policies. In the short and medium term, dairy development programs in Ethiopia will have a better chance of success if they target farmers who have better resource endowments and who are connected to better-functioning value chains rather than blanket technology scaling-up strategies targeting the majority of smallholders. Future agricultural research needs to shift the focus from predominantly developing new biophysical technologies towards social science research that assesses issues at value chain, macroeconomic institutions and policies that influence adoption of technology.

A. Schlageter Tello: Performance of raters to assess locomotion in dairy cattle

On Wednesday 27 May 2015 Andrés Schlageter Tello has defended his thesis entitled: Performance of raters to assess locomotion in dairy cattle.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. P.W.G. Groot Koerkamp, Farm Technology Group

Co-promotors:

Dr. ir. E.A.M. Bokkers, Animal Production Systems Group

Dr. ir. C. Lokhorst, Animal Sciences Group

Abstract:

Locomotion scoring systems are procedures used to evaluate the quality of cows’ locomotion. When scoring locomotion, raters focus their attention on gait and posture traits that are described in the protocol. Using these traits, raters assign a locomotion score to cows according to a pre-determined scale. Locomotion scoring systems are mostly used to classify cows as lame or non-lame. A preselected threshold within the scale determines whether a cow is classified as lame or non-lame. Since lameness is considered an important problem in modern dairy farming evaluation of locomotion scoring systems is utmost important. The objective of this thesis was to evaluate the performance of raters to assess locomotion in dairy cattle in terms of reliability (defined as the ability of a measuring device to differentiate among subjects) and agreement (defined as the degree to which scores or ratings are identical). This thesis also explores possibilities for the practical application of locomotion scoring systems. In a literature review comprising 244 peer-reviewed articles, twenty-five locomotion scoring systems were found. Most locomotion scoring systems varied in the scale used and traits observed. Some of the most used locomotion scoring systems were poorly evaluated and, when evaluated, raters showed an important variation in reliability and agreement estimates. The variation in reliability and agreement estimates was confirmed in different experiments aiming to estimate the performance of raters for scoring locomotion and traits under different practical conditions. For instance, experienced raters obtained better intrarater reliability and agreement when locomotion scoring was performed from video than by live observation. In another experiment, ten experienced raters scored 58 video records for locomotion and for five different gait and posture traits in two sessions. A similar number of cows was allocated in each level of the five-level scale for locomotion scoring. Raters showed a wide variation in intra- and interrater reliability and agreement estimates for scoring locomotion and traits, even under the same practical conditions. When agreement was calculated for specific levels when scoring locomotion and traits, the lowest agreement tended to be in level 3 of a five-level scale. When a multilevel scale was transformed into a two-level scale, agreement increased, however, this increment was likely due to chance. The variation in reliability and agreement is explained by different factors such as the lack of a standard procedure for assessing locomotion or the characteristics of the population sample that is assessed. The factor affecting reliability and agreement most, however, is the rater him/herself. Although the probability for obtaining acceptable reliability and agreement levels increases with training and experience, it is not possible to assure that raters score cows consistently in every scoring session. Given the large variation in reliability and agreement, it can be concluded that raters have a moderate performance to assess consistently locomotion in dairy cows. The variable performance of raters when assessing locomotion limits the practical utility of locomotion scoring systems as part of animal welfare assessment protocols or as golden standard for automatic locomotion scoring systems.

F. Pashaei Kamali: Sustainability performance of soybean and beef chains in Latin America

On Friday 18 December 2015 Farahnaz Pashaei Kamali has defended her thesis entitled: Sustainability performance of soybean and beef chains in Latin America.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is under embargo until January 2018

Promotors:

Prof. dr. A.G.J.M. Oude Lansink, Business Economics Group

Prof. dr. ir. I.J.M. de Boer, Animal Production Systems Group

Co-promotor:

Dr. ir. M.P.M. Meuwissen, Business Economics Group

Abstract:The objective of this thesis, was to analyze the sustainability performance of soybean and beef production chains in Latin America (LA). First identifying a set of sustainability issues of soybean and beef production chains in a LA-EU context was carried out. Sustainability issues were found to vary across stakeholders’ interests. Next, the environmental and economic performance of four feeding strategies for beef production in southern Brazil were evaluated.

2014

L.E. Webb: Food for Rumination. Developing novel feeding strategies to improve the welfare of veal calves

On Friday 31 October 2014 Laura Webb has defended her thesis entitled: Food for rumination - Developing novel feeding strategies to improve the welfare of veal calves.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. I.J.M. de Boer, Animal Production Systems Group

Co-promotors:

Dr. ir. E.A.M. Bokkers, Animal Production Systems Group

Dr. ir. C.G. van Reenen, Animal Sciences Group

Abstract:

Veal calves are typically fed high quantities of milk replacer supplemented with solid feed, which tends to contain a relatively small portion of roughage. Feeding strategies used in veal production have been associated with welfare issues, including the development of abnormal oral behaviours (AOB) and poor gastrointestinal health. AOB mainly include tongue playing and excessive oral manipulation of the environment, and are thought to develop in calves when chewing activity (i.e. eating and rumination) is not adequately stimulated. The aim of this thesis was to develop novel feeding strategies to improve the welfare of veal calves, i.e. to minimise the development of AOB and gastrointestinal health disorders.

Increasing solid feed provision stimulated chewing activity and reduced AOB frequency, although this was less true for solid feed mixtures comprising a large proportion of concentrate (i.e. 80%). The relationship between the amount of solid feed provided and AOB, however, was not straightforward. If calves experience a decrease in chewing activity as they grow older, their welfare may be compromised. Solid feed provision should be increased throughout the fattening period to meet the growing need of calves for structure in their feed. Moreover, ad libitum provision of hay, a roughage source with both high levels of structure and fermentable fibre, seemed to meet all three objectives of encouraging rumination and rumen development without exacerbating abomasal damage. If hay is omitted in veal production due to its high iron content, then multiple roughage sources should be provided to calves that together provide sufficient structure and fermentable fibre. The simple addition of ad libitum long straw to a typical veal diet (with a high concentrate proportion) seemed to improve behaviour, and therefore, welfare, significantly.

Calves preferred milk replacer, concentrate and hay over straw and maize silage, although preferences varied across age and depended on the variable considered to assess preference (i.e. intake, time spent eating or frequency of visits). Calves were willing to work for hay and straw, despite being fed a high-energy diet of milk replacer and concentrate. In addition, they showed a preference for long over chopped hay, but not long over chopped straw. Calves voluntarily selected an average of 1000 g DM roughage and 2000 g DM concentrate on top of milk replacer (provided ad libitum), and seemed to select a diet that enabled them to meet their needs in terms of chewing activity.

Novel feeding strategies aimed at improving the welfare of veal calves should comprise sufficient roughage to meet every individual's needs in terms of chewing activity, and this throughout their lifetime, whilst stimulating good gastrointestinal health.

J. Upton: Strategies to reduce electricity consumption on dairy farms - An economic and environmental assessment

J. Upton

On Wednesday 1 October 2014 John Upton has defended his thesis entitled: Strategies to reduce electricity consumption on dairy farms - An economic and environmental assessment.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotors:

Prof. dr. ir. I.J.M. de Boer, Animal Production Systems Group

Prof. dr. ir. P.W.G. Groot Koerkamp, Farm Technology Group

Co-promotor:

Dr. ir. L. Shalloo, Livestock Systems Department, Teagasc, Ireland

Abstract:

The aim of this thesis was to assess how, and to what extent, do managerial and technology changes affect electricity consumption, associated costs and greenhouse gas (GHG) emissions of dairy farms. Dairy farms in Ireland are expected to expand in the future, due to policy incentives and the abolishment of European Union milk quotas in 2015, which will result in an increased use of resources such as land, water, and energy, and increased emissions to the environment. In order to develop strategies to reduce electricity consumption associated costs and GHG emissions, it was necessary to understand the consumption trends and the hot-spots of electricity consumption within the farm. Therefore, we performed a life cycle assessment by quantifying the energy use on 22 commercial Irish dairy farms, from cradle-to-farm-gate.

This analysis demonstrated that a total of 31.7 MJ of energy was required to produce one kg of milk solids, of which 20% was direct and 80% was indirect energy use. Electricity consumption was found to represent 12% of total cradle-to-farm-gate energy use or 60% of direct energy, and was centered on milk harvesting. Following this analysis we devised two main groups of strategies, i.e. ‘cost strategies’ and ‘energy strategies’. ‘Cost strategies’ consisted of measures that could save on-farm costs but no energy or related emissions, such as, moving to a new electricity tariff or decoupling large electricity users, such as water heating, from milking times and shifting them to off-peak periods when electricity price is lower. Examples of ‘energy strategies’ are; the use of variable speed vacuum pumps on the milking machine, pre-cooling of milk and solar thermal technologies to provide hot water for cleaning purposes. A mechanistic model of electricity consumption that simulates farm equipment on an hourly and monthly basis was developed to further evaluate the ‘cost’ and ‘energy’ strategies. We used this model to show that a Day & Night electricity tariff minimised annual electricity costs, while a Flat tariff would increase the electricity costs by between 16% and 34%, depending on farm size. We also discovered that milking earlier in the morning and later in the evening reduced the simulated annual electricity consumption and related GHG emissions by between 5% and 7%, depending on farm size.

An analysis of ‘energy strategies’ was carried out which revealed that that the ideal blend of technologies to maximise farm profitability while also reducing electricity consumption and GHG emissions, consisted of a direct expansion milk tank with pre-cooling of milk with well water to 15°C, electrical water heating and standard vacuum pumps. An individual farmer can also choose to increase his or her use of renewable energy by adding solar thermal water heating with the trade-off of reduced profitability and negative return on investment figures. This analysis highlighted the need for an investment appraisal approach to technology investments on dairy farms.

D. Oseguera Montiel: Keeping goats or going north? Enhancing livelihoods of smallholder goat farmers through Brucellosis control in Mexico

dryseason.jpg

D. Oseguera Montiel

On Monday 25 August 2014 David Oseguera Montiel has defended his thesis entitled: Keeping goats or going north? Enhancing livelihoods of smallholder goat farmers through Brucellosis control in Mexico.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. A.J. van der Zijpp

Co-promotors:

Dr. ir. H.M.J. Udo, Animal Production Systems Group

Dr. ir. K. Frankena, Quantitative Veterinary Epidemiology Group

Abstract:

Smallholder Mexican farmers are embedded in an adverse context, due to neoliberal globalization policies, which threatens their livelihoods, and has caused an unprecedented surge of migration to the US. Keeping goats is one strategy to diversify livelihoods. Goat husbandry is dairy oriented and has a range of functions for farmers, like income, food, insurance, credit, and a reason for not having to migrate to the US. However, caprine brucellosis, a zoonosis endemic in Mexico caused by Brucella melitensis, has a negative impact on flock productivity. Although brucellosis is rarely a fatal disease in humans, it can be very debilitating and disabling due to complications such as arthritis and spondylitis. The main objectives of this thesis were to assess the impact of brucellosis on smallholder goat husbandry and to evaluate brucellosis control strategies in enhancing farmers’ livelihoods. The research approach was that of a case study, incorporating methods from natural and social sciences, such as archival and secondary data review, surveys, ethnography and veterinary epidemiological modelling. The case study was conducted in two states within the Bajío region with high rates of migration: Michoacán and Jalisco. In Michoacán free cost vaccination and testing was applied whereas in Jalisco farmers had to bear part of those costs and there was a lack of veterinarians offering the service.

Goat farmers considered that they were better off than farmers who did not keep goats: ‘it is better to herd than to be herded’. Farmers’ knowledge, labour and good social capital allowed them to maintain relatively large flocks given the amount of crop land owned. The prevalence of testing positive to brucellosis in goats was 38% in Jalisco and 11% in Michoacán. Access to communal land and crop residues were key for the pastoral management system prevalent in the study area, but grazing goats had higher risk of testing positive to brucellosis. Farmers avoided drinking goat milk, as it was seen as a cause of ‘fever’. The milk price was low and controlled by the caramel industry. Vaccination and testand-cull strategies are options to control brucellosis. Simulations showed that vaccination is economically feasible but will not bring the prevalence below to 10% within 5-years. Testand-slaughter is not economically rewarding at the current milk price. At present, culling of seropositive goats to brucellosis does not happen because an adequate infrastructure for culling does not exist. Farmers perceived that brucellosis control measures cause losses such as abortion due to untimely vaccination and infections due to ear tagging. Moreover, farmers did not always know that brucellosis and Malta fever (human brucellosis) are synonyms, neither were they aware of all consequences of brucellosis infection.

Brucellosis control is stagnant because of a two way lack of communication: farmers are not well informed about brucellosis and policies are formulated without knowledge of goat farming practices and of farmers’ perceptions. Successful brucellosis control would enhance smallholder goat farmers’ livelihoods but the control policy needs to be redesigned. Important factors to consider in the design of a new policy are: (1) a comprehensive compensation for losses when applying test-and-cull; (2) the integration of farmers’ expertise and experience; (3) diffusion of knowledge about brucellosis control, its prevention and its impact on human health and livestock production; (4) a regional planning is a must to succeed.

C.E. van Middelaar: Milk production & greenhouse gases. Integrated modeling of feeding and breeding strategies to reduce emissions

Corina thesis.jpg

C.E. van Middelaar

On Friday 13 June 2014 Corina van Middelaar has defended her thesis entitled:  Milk production & greenhouse gases. Integrated modeling of feeding and breeding strategies to reduce emissions.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. I.J.M. de Boer

Co-promotors:

Dr. ir. P.B.M. Berentsen, Business Economics Group

Dr. ir. J. Dijkstra, Animal Nutrition Group

Abstract:

Dairy cattle are responsible for about 30% of global greenhouse gas (GHG) emissions produced by the livestock sector. Main sources of emissions are enteric fermentation (methane), feed production (mainly carbon dioxide and nitrous oxide), and manure management (methane and nitrous oxide). The research described in this thesis aims to develop an integrated method to evaluate strategies to reduce GHG emissions from dairy production at the chain level, and to evaluate feeding and breeding strategies using this integrated method. We first explored consequences of differences in methods and data to calculate emissions from feed production, and decided upon a standard life cycle assessment (LCA). Subsequently, we integrated a whole-farm optimization model with an LCA of purchased inputs, and a mechanistic model to predict enteric methane production. We used this integrated method to evaluate the impact of several feeding and breeding strategies on GHG emissions at chain level and on labor income at farm level. All strategies were evaluated for the case-study of a typical Dutch dairy farm on sandy soil. The relevance of integrated modeling was demonstrated by evaluating the impact of increasing maize silage at the expense of grass and grass silage in a dairy cow’s diet at animal, farm, and chain levels.

At animal level, the strategy results in an immediate reduction in GHG emissions. At farm and chain levels, it takes more than 60 years before annual emission reduction has paid off emissions from land use change. Results confirmed the importance of integrated modeling. Subsequently, other feeding strategies were evaluated, including dietary supplementation of extruded linseed, dietary supplementation of nitrate, and reducing the maturity stage of grass and grass silage. Each feeding strategy reduced GHG emissions along the chain. Supplementing diets with nitrate resulted in the greatest reduction, but reducing grass maturity was most cost-effective (i.e. lowest costs per ton CO2-equivalents reduced). In case of breeding, two methods were explored to determine the relative importance of individual traits to reduce GHG emissions along the chain (i.e. the relative GHG value): the first method aims at maximizing labor income, the second at minimizing GHG emissions per kg milk. GHG values were calculated for one genetic standard deviation change of milk yield and longevity, while robustness of results was explored by comparing GHG values for an efficient and a less-efficient farm. The GHG values of both milk yield and longevity were at least twice as great when focus was on minimizing GHG emissions. Furthermore, the GHG value of milk yield was greater than that of longevity when focus was on maximizing labor income, especially for the less efficient farm. When focus was on minimizing GHG emissions, both traits were equally important on each level of efficiency. To substantially reduce GHG emissions from dairy production, a combination of strategies is required.


H. Leruste: Assessing welfare of veal calves on farms. Measures of behaviour and respiratory disorders and potential ways for welfare improvement

helene.JPG

H. Leruste

On Friday 14 March 2014 Hélène Leruste has defended her thesis entitled:  Assessing welfare of veal calves on farms. Measures of behaviour and respiratory disorders and potential ways for welfare improvement.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. B. Kemp, Adaptation Physiology Group

Co-promotors:

Dr. ir. E.A.M. Bokkers, Animal Production Systems Group

Dr. ir. B.J. Lensink, ISA group, France

Abstract:

In Europe, minimal standards for the protection of veal calves are defined in EU directives but do not necessarily guarantee a sufficient level of animal welfare at all farms. The European Union supported a research program called Welfare Quality® from 2004 to 2009, which aimed at “developing a standardized monitoring system of animal welfare” and “identifying practical solutions to improve animal welfare”. The objective of the present thesis was to develop and validate a number of measures on veal farms including measures related to the assessment of human-animal relationship, abnormal oral behaviours, and respiratory disorders. In that perspective, a number of measures were tested for their validity, reliability and feasibility and specific risk factors for impaired welfare at farm level were identified. Data were collected on 174 farms in the three main veal producing countries in Europe (France, the Netherlands and Italy). Farms were visited at several time point during fattening and observations were performed at slaughter. Several behavioural tests for the assessment of human-animal relationship were validated as they showed good test-retest and inter-observer repeatability and were feasible on farms. Total number of calves on the farm, number of calves per stockperson, space allowance, type of milk distribution environmental enrichment, stockperson’s experience, breed and season of observation influenced the outcome of the human-animal relationship tests. Veal calves raised under intensive conditions may express abnormal oral behaviours as signs of mental suffering and reduced welfare. The observation of these abnormal oral behaviour of calves could be performed by direct observation which prooved to be a more suitable observation method than observations from video recordings for these behaviours in veal calves even though the presence of an observer had a short term effect on abnormal oral behaviours of calves. Again, factors such as space allowance, farmer’s experience, breed of calves and season but also type of solid feed, amount of milk, number of calves per pen and babybox use influenced the expression of abnormal oral behaviour in veal calves. The presence and severity of lung lesions recorded post-mortem is commonly used as an indicator to assess the prevalence of respiratory problems in batches of bovines. In the context of welfare assessment based on on-farm measures, the recording of clinical signs on calves at the farm would be more convenient than the recording of lung lesions at slaughter. Regardless of the stage of fattening, the prevalence of in vivo signs of respiratory disorders in calves was low However, at postmortem inspection, a significant proportion of lungs evaluated showed mild/moderate or and severe signs of pneumonia. Clinical signs of respiratory disorders were not enough predictive of lung lesions and therefore both measures are to be kept in the monitoring system tools. Different risk factors for respiratory disorders were involved at different stages of the fattening period. Among all potential risk factors considered, those concerning the characteristics of the batch were predominant but factors related to housing, management and feeding equipment were also relevant. This thesis showed that animal-based measures on human animal relationship, abnormal oral behaviours and respiratory disorders are valid and contribute reliably to assess the welfare of veal calves. In addition, some conditions were identified that should be considered carefully in welfare assessment. The study allowed assessing multiple factors across farms that influenced the outcome of welfare measures assessed in veal calves. These factors imply a potential negative or positive impact on welfare. Knowing these factors can help in advising farmers in their effort to improve welfare of veal calves although the biological causality between some factors and the welfare measures is not always known.

J.W. de Vries: From animals to crops - Environmental consequences of current and future strategies for manure management

Jerke omgekeerde osmose.jpg

J.W. de Vries: From animals to crops - Environmental consequences of current and future strategies for manure management

On Friday 17 January 2014 Jerke de Vries has defended his thesis entitled:  From animals to crops - Environmental consequences of current and future strategies for manure management.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotors:

Prof. dr. ir. I.J.M. de Boer

Prof. dr. ir. P.W.G. Groot Koerkamp, Farm Technology Group

Co-promotors:

Dr. ir. W.B. Hoogmoed,  Farm Technology Group

Dr. ir. C.M. Groenestein, Wageningen UR Livestock Research

Abstract:

Animal manure is a key component that links crop and livestock production as it contains valuable nutrients for the soil and crop. Manure is also a source of environmental pollution through losses of nutrients, such as nitrogen (N) and phosphorus (P), and losses of carbon (C). These losses are largely determined by the way manure is managed. Technologies to reduce nutrient and C losses from manure mainly focused on reducing a single emission while unwillingly increasing another emission at the same time; a phenomenon called pollution swapping. To prevent pollution swapping, we need to gain insight into the integral environmental consequences of technologies and use these insights to (re)design the manure management chain. The aim of this thesis, therefore, was to provide knowledge and insight into the environmental consequences of current and future strategies for manure management.

The environmental consequences of the following technologies were assessed: mono- and co-digestion of liquid manure; high-tech separation of liquid manure with further dewatering of the liquid fraction; and segregating fattening pig urine and feces inside the housing system. Following, we designed new strategies for integrated manure management that prevent pollution swapping, and assessed the environmental consequences of these strategies. Life cycle assessment was used to calculate the environmental impacts of current and future strategies. For the design, we adapted and used a structured approach to engineering design to create new strategies for integrated manure management.

It was concluded that mono-digestion of liquid manure reduced the environmental impact compared to conventional manure management, but has a low potential to produce bio-energy. Co-digestion with waste and residues, such as roadside grass, increased bio-energy production and further reduced the environmental impact. Co-digestion with substrates that compete with animal feed increased bio-energy production, but also the overall environmental impact from producing a substitute for the used co-substrate. Separating liquid manure into liquid and solid fractions with further de-watering of the liquid fraction increased the environmental impact compared to manure management without processing. A combination of separation and anaerobic mono-digestion of the solid faction reduced climate change and fossil fuel depletion. Segregating fattening pig urine and feces in the housing system reduced climate change, terrestrial acidification, and particulate matter formation and provided a sound basis for environmentally friendly manure management.

Applying a structured design approach enabled the design of new strategies for integrated manure management that prevented pollution swapping. The approach proved to be successful because the environmental impact reduced throughout the manure management chain by at least 57% and more than doubled the nitrogen use efficiency compared to current North Western European manure management practices.


2013

K. Amankwah: Enhancing food security in Northern Ghana through smallholder small ruminant production and marketing

K. Amankwah: Enhancing food security in Northern Ghana through smallholder small ruminant production and marketing

On Thursday 12 December 2013 Kwadwo Amankwah has defended his thesis entitled:  Enhancing food security in Northern Ghana through smallholder small ruminant production and marketing.

The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. A.J. van der Zijpp

Co-promotors:

Dr. ir. L.W.A. Klerkx, Knowledge, Technology and Innovation Group, Wageningen University

Dr. O. Sakyi-Dawson, Department of Agricultural Extension, University of Ghana, Accra, Ghana

Dr. N. Karbo, Animal Research Institute, Council for Scientific and Industrial Research (CSIR), Accra, Ghana

Abstract:

Livestock is the source of livelihood and food security for two-thirds of the rural poor in developing countries. This study examined the combined technical and institutional constraints that hinder  smallholder livestock production and marketing in Northern Ghana and  how interventionists and farmers themselves sought to resolve the constraints over the past 20 years.

The constraints farmers experienced were diseases, lack of water during dry season and theft. Resilient strategies of most  farmers involved  keeping livestock as capital stock and insurance against crop failure and emergency cash needs,  low input use and sufficient  volume of  livestock production. Three public interventions (1996 – 2009) were characterised by the interventionists’ inability to learn from farmers and their tendency for prescriptive solutions and consequent marginal adoption of intervention outcomes.

It was concluded that household food security is a significant driver of current (non-commercial) livestock production, self-organized responses to surrounding conditions, and selective use of intervention outcomes. 


E. Ruiz Izaguirre: A village dog is not a stray: human-dog interactions in coastal Mexico

DSCN0701_341.JPG

E. Ruiz Izaguirre: A village dog is not a stray: human-dog interactions in coastal Mexico

On Monday 14 October 2013 Eliza Ruiz Izaguirre has defended her thesis entitled:  A village dog is not a stray: human-dog interactions in coastal Mexico.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. I.J.M. de Boer

Co-promotor:

Dr. ir. C.H.A.M. Eilers

Abstract:

Dogs (Canis familiaris) are considered one of the most numerous carnivores worldwide. Although in the Global North dogs are popular companions, that live inside homes, about 80% of the dogs in the world are village dogs. Village dogs are typically free-roaming, scavenge refuse around human dwellings and are associated with one or various households. At present, village dogs in the Global South are a concern for (inter)national organizations and individuals, such as tourists. Concerns arise about: overpopulation, transmission of zoonoses, welfare of village dogs, and issues relating to dog–wildlife interactions, such as predation on wildlife. Dog culling has proved ineffective in managing dog populations, in controlling zoonoses, and preventing wildlife predation, but remains the dominant strategy to manage village dogs in Mexico. The objective of this thesis was to improve the understanding of human–dog interactions in coastal areas of Mexico in order to identify strategies - embedded in the social and cultural context - to manage village dogs. The Pacific Coast of Mexico was used as a case study area because of its high dog density and its importance for tourism and sea-turtle nesting. Village dogs interact with tourists and are known to scavenge sea-turtle nests. Conclusions presented are based on fieldwork conducted in three villages in Oaxaca and two in Michoacán. This fieldwork comprised, among others, interviews with villagers, dog behavioral tests, and radio-tracking of village dogs.

Village dogs that live nearby nature protected areas are part of three main systems: the household, the village, and the nature protected area. Humans keep dogs mainly for guarding, as work companions and as children’s playmates. At household level, dogs interact with familiar (i.e. caregivers) and unfamiliar humans (e.g. visitors). At village level, dogs interact with familiar humans from other households, or with unfamiliar humans, such as tourists. At all system levels, village dogs have experiences with humans that may range from positive to negative, and this may be reflected in their behavioral responses towards humans. Dogs reported to engage in human-dog play (mainly with children) were more likely to respond with tail wagging to a caregiver’s call and to approach an unfamiliar human. Dogs can enter a nature protected area (i.e. sea-turtle nesting beach) by themselves or with other dogs or humans. Food is a central element in the above-described holistic system. Village dogs scavenge for food in proximity to humans, beg for food, or prey on sea-turtle eggs. Body condition of village dogs was in general close to optimal, and dogs maintained body condition also in the low season for sea-turtle nesting and tourism. Nest scavenger dogs, however, had a lower metabolic energy intake of tortillas, and a larger mean distance from home compared to non-nest scavengers. This suggests that nest scavenging is hunger-driven, and therefore, solutions need to focus on caregivers’ feeding practices.

The keeping of dogs in the above-described system, is subject to clashing perceptions and discourses of external (e.g. tourists, authorities) and internal (villagers) stakeholders. External stakeholders refer to village dogs as stray or abandoned, and any dog that is not totally dependent on humans (e.g. village dog) is considered out of place. Total dependence of dogs on humans is a logical ethical argument deriving from the idea that humans took dogs out of the wild (in line with the ‘Pinocchio theory’). Villagers’ narratives, in contrast, perceive dogs as autonomous and able to take care of themselves (in line with the Village Dog theory of dog self-domestication). Dog welfare problems (i.e. dogs being too thin or sick) in coastal Oaxaca were perceived more by international than by Mexican tourists. Dog predation of sea-turtle nests was an important concern for tourists, but not for internal stakeholders.

In conclusion, the findings of this thesis show that village dogs in coastal Mexico are not ‘stray’, but interact with familiar humans from one or various households. Interactions of dogs with humans surpass a purely ecological relationship, as village dogs also fill a social niche and have important functions. Current policies and attempts to manage village dog populations in Mexico are derived from discourses and experiences largely disconnected from the village context. In order to find possible strategies to manage village dog populations, it is necessary to acknowledge the complexity of human–dog interactions, and include the views of both external and internal stakeholders.


M. de Vries: Assuring dairy cattle welfare: towards efficient assessment and improvement

M. de Vries: Assuring dairy cattle welfare: towards efficient assessment and improvement

On Tuesday 18 June 2013 Marion de Vries has defended her thesis entitled: Assuring dairy cattle welfare: towards efficient assessment and improvement.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotor:

Prof. dr. ir. I.J.M. de Boer

Co-promotors:

Dr. ir. E.A.M. Bokkers

Dr. T. Dijkstra, Animal Health Service, Deventer

Abstract:

In many countries, there is an increasing interest to assure the welfare of production animals. On-farm assessment of dairy cattle welfare, however, is time-consuming and, therefore, expensive. Besides this, effects of housing and management interventions that are aimed at improving welfare can be conflicting for different indicators of dairy cattle welfare. The research described in this thesis aimed to contribute to assurance of dairy cattle welfare by evaluating strategies to improve time-efficiency of welfare assessment and by identifying housing and management interventions for welfare improvement. Results presented are based on an observational study among 194 selected Dutch dairy herds. From these herds, data relating to housing, management, and indicators of the Welfare Quality (WQ) protocol for dairy cattle was collected on-farm, and routine herd data (RHD), relating to demography, management, milk production, milk composition, and fertility, was extracted from several national databases. Because in many countries RHD are regularly collected from dairy farms, it was hypothesized that RHD could be used to identify herds with potentially poor animal welfare and, therefore, reduce the number of on-farm assessments that are needed to identify these herds.

Results of the literature review showed that variables of RHD have been associated with almost half of the welfare indicators in the WQ protocol for dairy cattle. When RHD and welfare data collected in the observational study were used to evaluate the value of RHD for predicting dairy cattle welfare at the herd level, predictions based on RHD for welfare indicators varied from less to highly accurate. For most welfare indicators, therefore, RHD can serve as a pre-screening test for detecting herds with poor welfare and reduce the number of on-farm assessments. In order to decide whether a herd should be visited following a pre-screening, however, value judgments about the overall welfare of herds need to be made. This requires combining welfare indicators in an overall score that reflects the multidimensional nature of welfare and the relative importance of indicators. The relative importance of indicators was evaluated for welfare classification of our study herds based on the WQ multicriteria evaluation model. Results showed that a limited number of indicators had a strong influence on classification of herds, and classification was not very sensitive to indicators of good health, such as prevalence of severely lame cows. As a different strategy for improving time-efficiency of welfare assessment, reduction of the time per on-farm assessment of the WQ protocol for dairy cattle was explored. Reduction of on-farm assessment time was simulated by omitting welfare indicators from the WQ protocol, and replacing observed values of omitted indicators by predictions based on remaining welfare indicators in the protocol. Because results showed that agreement between predicted and observed values of indicators was poor to moderate, it was concluded that this strategy has little potential to reduce on-farm assessment time. To contribute to knowledge of housing and management interventions that may lead to improvement of dairy cattle welfare, housing and management factors associated with various indicators in the WQ protocol were identified and compared. Surface of the lying area and pasturing in summer were commonly associated with the prevalence of lameness, lesions or swellings, and dirty hindquarters, but no common risk factors were identified for the average frequency of displacements and other welfare indictors.

In conclusion, the present work shows that routine herd data can be used to improve time-efficiency of welfare assessment, whereas replacing welfare indicators by predictions based on other welfare indicators cannot. The WQ multicriteria evaluation model for classification of dairy cattle welfare has limitations in its current form. A softer surface of the lying area and pasturing in summer can enhance simultaneous improvement of multiple welfare indicators.

2012

S.E.M. Dekker: Exploring ecological sustainability in the production chain of organic eggs

S.E.M. Dekker: Exploring ecological sustainability in the production chain of organic eggs

On Friday 20 April 2012 Sanne Dekker has defended her thesis entitled: Exploring ecological sustainability in the production chain of organic eggs.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is available as pdf

Promotors:

Prof. dr. ir. I.J.M. de Boer

Prof. dr. ir. P.W.G. Groot Koerkamp, Farm Technology Group

Co-promotor:

Dr. ir. A.J.A. Aarnink, Livestock Research

Abstract:

Organic eggs are produced in loose production systems with an outdoor run and without use of artificial fertilizers, pesticides, GMO’s, and limited use of medication. But what does this mean for the ecological impact of organic eggs? The ecological impact of organic, free range and barn eggs is higher than battery cage eggs. Compared with free range and barn eggs, organic eggs cause less climate change, require less fossil fuel and fossil phosphorus and have a lower nitrogen and phosphorus surplus. Production of organic eggs, however, requires more land, ammonia emission is higher, and local nitrogen and phosphorus soil deficits occur. Ecological impact of organic eggs can be reduced by: sufficient and balanced nitrogen and phosphorus fertilization, avoidance of nitrogen and phosphorus losses to the outdoor run, switching to aviary housing with a low ammonia emission, feeding co-products, and efficient conversion of feed to eggs. Production of sustainable organic eggs, therefore, requires cooperation between all production chain parties.


P. Chaminuka: Evaluating land use options at the wildlife/livestock surface: An integrated spatial land use analysis

P. Chaminuka: Evaluating land use options at the wildlife/livestock surface: An integrated spatial land use analysis

On Wednesday January 18 2012 Petronella Chaminuka has defended her thesis entitled: Evaluating land use options at the wildlife/livestock surface: An integrated spatial land use analysis.

View the ceremony via WUR-TV archive. The full text of the PhD-thesis is under embargo until February 2014

Promotors:

Prof.Dr.Ir. A.J. van der Zijpp, Animal Production Systems Group

Prof.Dr. E.C. van Ierland, Environmental Economics and Natural Resources Group

Prof.Dr. C.M.E. McCrindle, Department of Paraclinical Sciences, University of Pretoria, South Africa

Co-promotor:

Dr.Ir. R.A. Groeneveld, Environmental Economics and Natural Resources Group

Abstract:

In Africa, rural development and biodiversity conservation are both important, but sometimes potentially conflicting priorities. Most rural areas adjacent to wildlife protected areas in Southern Africa are faced with problems of crop destruction, and livestock depredation by wildlife. Transfrontier conservation areas (TFCAs), have potential to address both biodiversity and poverty alleviation through promotion of multiple land uses such as wildlife ranching, tourism, livestock and crop production. It is however, not clear how these land uses can be combined, and what the associated socio-economic costs and benefits of alternative land use options in these areas are. This study proposed a spatial land use model for evaluating alternative land uses and development pathways in these rural areas. The model maximised net revenues from the land, assuming the presence of a social planner. The model proposed, considered a range of socio-economic and biophysical factors, identified jointly with rural communities. The case study area was Mhinga, one of the rural areas within the Great Limpopo TFCA in South Africa. Results showed that the costs by wildlife related damage such as livestock depredation and diseases were higher than the benefits in employment and subsidies from the park for households. As a consequence attitudes towards wildlife by farmers were generally negative. Households living closer to the park had more problems with wildlife damage. When the contributions of different livelihood activities to household incomes were considered, the main sources of income were the government welfare grants, formal employment and cattle farming.

Cattle farmers were not in support of introducing wildlife based land use activities as they considered them to impose costs on other livelihood activities. Some community members were however of the opinion that introducing wildlife tourism could create employment and improve household incomes, especially for those households not engaged in cattle farming. Analysis of options for land based development showed that existing land use practices, which were mainly livestock based, were not optimal. By introducing irrigation, tourism and wildlife land uses, net revenues from land could be doubled in the future. It is concluded that, given the socio-economic and bio-physical constraints characteristic to the area, most income can be obtained by combining livestock, irrigation, tourism and wildlife land uses in the area in optimal proportions. Factors such as property rights and benefits distribution which could impact the ability of rural communities in the TFCA to support, utilize and benefit from wildlife resources need to be addressed before any land use changes are implemented.