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Typology of contract farming arrangements: a transaction cost perspective
No full textThis paper proposes an alternative typology of contract farming arrangements (CFA) based on transaction cost theory. To construct the typology, we first surveyed managers of agribusiness firms and contracted farmers in Zimbabwe to understand the provisions in their contracts, the motivations for their inclusion and the level of transaction attributes, particularly the sub-categories of asset specificity and uncertainty. We then developed a two-by-two matrix of contract types based on the interaction of transaction attributes. The results show that four contract types can be distinguished: total, group, lean and market contracts. Furthermore, CFAs that are misaligned with transaction attributes have problems of side-selling and inefficiency. Our new empirically based categorisation can help managers and policymakers to design CFAs that match with underlying transaction attributes, thus enhancing the stability and efficiency of CFAs.</p
Energy consumption on dairy farms: A review of monitoring, prediction modelling, and analyses
No full textThe global consumption of dairy produce is forecasted to increase by 19% per person by 2050. However, milk production is an intense energy consuming process. Coupled with concerns related to global greenhouse gas emissions from agriculture, increasing the production of milk must be met with the sustainable use of energy resources, to ensure the future monetary and environmental sustainability of the dairy industry. This body of work focused on summarizing and reviewing dairy energy research from the monitoring, prediction modelling and analyses point of view. Total primary energy consumption values in literature ranged from 2.7 MJ kg-1 Energy Corrected Milk on organic dairy farming systems to 4.2 MJ kg-1 Energy Corrected Milk on conventional dairy farming systems. Variances in total primary energy requirements were further assessed according to whether confinement or pasture-based systems were employed. Overall, a 35% energy reduction was seen across literature due to employing a pasture-based dairy system. Compared to standard regression methods, increased prediction accuracy has been demonstrated in energy literature due to employing various machine-learning algorithms. Dairy energy prediction models have been frequently utilized throughout literature to conduct dairy energy analyses, for estimating the impact of changes to infrastructural equipment and managerial practices.</p
Growth under fluctuating light reveals large trait variation in a panel of arabidopsis accessions
No full textThe capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non‐photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.</p
Surplus of dietary micronutrients promotes antioxidant defense and improves fin erosions in European seabass (Dicentrarchus labrax) fry
No full textDietary micronutrient supplementation can serve as skin health promotor to prevent from natural infections and can be applied to decrease the use of antibacterial agents and their impact on the environment. Such supplementation has indicated anti-inflammatory and antioxidant properties in farmed fish. In this study, dietary supplementation of zinc, selenium, ascorbic acid and niacin, at levels 2 to 3-fold higher than recommended, was evaluated as a measure to promote skin health and antioxidant defense in European seabass, Dicentrarchus labrax, fry. For this purpose, fish survival, growth performance, fin and skin erosions as well as whole-fish antioxidant enzyme activity (catalase, selenium (Se)-independent and dependent glutathione peroxidase) were assessed. Moreover, bacterial load in the rearing water and skin mucus were evaluated to assess the potential of the dietary micronutrient mixture as a preventive from natural infections. A group fed with a diet including these micronutrients at recommended levels served as a control. Surplus of these micronutrients significantly reduced the percentage of fish with eroded fins, while also induced the activity of catalase and Se-dependent glutathione peroxidase. Fish growth and bacterial loads in the water and fish skin mucus were not affected, whereas no skin lesions were observed. Overall, a mineral- and vitamin-supplemented diet at levels higher than recommended seems to act as a promotor of skin health and prevent from fin erosions, potentially through an increase in the antioxidant defense system.</p
Nature-Inclusive Design: a catalogue for offshore wind infrastructure : Technical report
No full textOffshore wind farms in the Dutch North Sea must make demonstrable efforts to stimulate native nature within the wind farm. For example, suitable scour protection or fish hotels can be placed around wind turbines that serve as nursery areas or offer shelter. Also flat oysters can be placed, which can form reefs and attract great biodiversity. Commissioned by the Ministry of Agriculture, Nature and Food Quality, Witteveen+Bos and Wageningen Marine Research have produced a catalog of such Nature Inclusive Design options. The catalog shows the target species for which the option is suitable, the expected construction costs, and where the materials can be purchased
IAG proficiency test feed composition 2019
No full textA proficiency test was organized for the microscopic determination and semi-quantification of botanic ingredients in the formulation of an animal feed, in the framework of the annual proficiency tests of the IAG - International Association for Feeding stuff Analysis, Section Feeding stuff Microscopy. The organizer of the proficiency test was Wageningen Food Safety Research, The Netherlands. The aim of the proficiency study was to provide the participants information on the performance of the local implementation of the method for composition analysis of feed. The current proficiency test was focusing on the control of the label declaration of the botanic composition of a ruminant feed. Participants received a sample of the ruminant feed and were asked to check the correctness of the label information. Therefore, the label declaration was provided together with the sample. The formulation as declared by the label showed the correct composition. Results should show the share of the different ingredients in percentages. Indicated shares were considered under- or overestimations when exceeding the limits of the IAG uncertainty interval model.A total of 22 sets of results was returned. Six of the nine ingredients had shares with intervals of which the lower limits were still higher than zero percent in the IAG estimation model. Correct estimation of these shares needs more precision than in a situation where only an upper limit applies. The reported shares of these six ingredients were within the limits of the uncertainty model in 87.9% of the total number of estimations. The correct estimations of all reports of the shares of nine ingredients is 80.3%. Six out of 22 participants delivered an errorless composition, which is 27%. Besides this, six participants made one error, three made two errors and two participants made three errors. There is no clear correlation with the method applied. Only three participants reported an indication of the correctness of the label. The current information on the capability of botanic composition analysis reveals that this technique is valuable as part of the enforcement of feed and food safety. The current lack of a complementary system for the analysis of chemical composition (ash, proteins, fat, dietary carbohydrates, fibres, etc.), which would provide parameters for the control of an established botanic composition, could be a drawback for the overall performance of the technique for botanic composition analysis. Besides a proper method description and up-to-date descriptions of ingredients, well developed skills of technicians are vital for a good performance. The use of an expert system as tool for maintenance and dissemination of expertise might improve future performance.The analysis of composition in terms of ingredients is important for detecting economic fraud and for monitoring feed safety. Botanic composition analysis and label control of feed is regulated in Regulation (EC) 767/2009. This technique can support traceability (Regulation (EC) 178/2002), for detection of fraud (Regulation (EU) 2017/625) and for categorization (Regulation (EU) 1308/2013; Regulation (EU) 2016/1821). In a broader view, composition analysis in the entire food chain can improve the effect of monitoring actions. The legislation on food labelling (Regulation (EC) 1169/2011) obliges to provide more detailed information to customers on composition and related topics
Detection of pyrrolizidine alkaloids in jamu available on the Indonesian market and accompanying safety assessment for human consumption
No full textThe occurrence and accompanying risks of pyrrolizidine alkaloids (PAs) in Indonesian jamu were evaluated. PAs were detected in 34 out of 35 jamu containing PA-producing botanicals, in the range of 12.3–235,376 μg/kg. A total PA level of 5.9–3,421 μg/kg was found in 17 out of 23 jamu made of non-PA-producing botanicals pointing to contamination with PA-producing plants. Short-time consumption of jamu is unlikely to result in acute toxic effects, although one sample would exceed an intake of 10 μg PA/kg bw/day which may cause hepatic veno-occlusive disease (HVOD) in humans. The risk assessment for the genotoxic and carcinogenic potential of PAs revealed Margin of Exposure (MOE) values below 10,000 for 27 out of all samples analysed (46.6%), indicating a priority for risk management when assuming daily lifelong consumption. Assuming consumption for two weeks every year during a lifetime, and using Haber's rule, 13 out of 35 jamu samples containing PA-producing botanicals (37%) still pose a priority, while the jamu consisting of non-PA-producing botanicals would be of low priority (MOE>10,000). This study provides data that can support risk management actions in Indonesia to minimize the potential health risk for jamu consumers due to the occurrence of toxic PAs in these products.</p
Predicting post-natal energy intake of lesser black-backed gull chicks by Dynamic Energy Budget modeling
No full textThe standard Dynamic Energy Budget (DEB) model is widely used to describe the physiology of individual animals. Here we parametrized the DEB model for the lesser black-backed gull Larus fuscus mainly on the basis of literature data. Next we performed an inverse modeling approach to predict the food intake rate of gull chicks (model input) on the basis of their growth trajectory from hatching to fledging (model output). Food intake rate and growth were also measured for this period in an aviary experiment, where three different diet treatments resulted in a large range in overall intake rate. These measured food intake rate data were not used in the parameter estimation procedure, but rather to validate model results. Model predictions of food intake rate were systematically only about 10% below the observations, but predictions and observations correlated strongly. The DEB model might be used to predict food provisioning rates in the field, which are difficult to obtain, on the basis of growth data, which are much easier to get.</p
Pilots naar de vermindering van fijnstofemissie uit pluimveestallen : DUSTion van Serutech-Agri/Optiklep
No full textTo mitigate the concentrations of fine particulate matter in livestock farming areas, techniques are needed which reduce emissions from poultry barns. In this pilot study, measurements were carried out on the DUSTion system of the companies Serutech-Agri and Optiklep, installed inside a broiler barn. In deviation from the measurement protocols, the so called “fine dust pilots” included one (instead of two) farm locations. The measurements show that the system reduces the emission of fine particulate matter (PM10) with 62%