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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Excreta emissions in progeny of low and high enteric methane yield selection line sheep fed pasture of different qualities
Jonker, A. ; MacLean, S. ; Woyimo Woju, C. ; Garcia Rendon Calzada, M. ; Yu, W. ; Molano, G. ; Hickey, S. ; Pinares-Patiño, C.S. ; McEwan, J.C. ; Janssen, P.H. ; Sandoval, E. ; Lewis, S. ; Rowe, S. - \ 2019
Animal Feed Science and Technology 257 (2019). - ISSN 0377-8401
Animal variation - Breeding value - Greenhouse gas - Nitrous oxide - Repeatability - Urine

Selection of sheep with low enteric methane (CH4) emissions is a greenhouse gas (GHG) mitigation option suitable for pastoral systems. However, the effect of breeding sheep with low enteric CH4 emissions on excreta output and associated CH4 and nitrous oxide (N2O) emissions and therefore total GHG emissions are not known. The objective of the current experiments were to determine excreta output, and estimate associated GHG emissions, from progeny of low and high enteric CH4 per unit of dry matter intake (DMI) selection line sheep (CH4/DMI). The animals were fed two qualities of cut perennial ryegrass-based pasture (very mature vs. vegetative, 12 animals per CH4/DMI line) in Exp. 1 and cut pasture in two repeated seasons (autumn and winter; 15 animals per CH4/DMI line × 2 seasons) in Exp. 2. Total faecal and urine output was determined on individual animals, followed by enteric CH4 emission measurements in respiration chambers. GHG emissions from urine (N2O) and faeces (CH4 and N2O) were estimated based on New Zealand Agricultural GHG Inventory methodology. There was no interaction between CH4/DMI selection line and diet quality in Exp. 1 or seasons in Exp.2. Total daily faecal output of DM, organic matter (OM) and neutral detergent fibre (NDF; all g/d) and associated calculated faecal CH4 emissions were greater for low compared to high CH4/DMI sheep in Exp. 1 (P < 0.05), while being similar between CH4/DMI selection lines in Exp. 2. Nitrogen (N) excretion and N partitioning into urine, faeces and body retention, and calculated excreta N emissions, were mostly similar between CH4/DMI selection line sheep in both experiments. Except, faecal N output (g/d and per unit of N intake) and associated calculated direct faecal N2O-N emissions (g/d) were greater in low compared to high CH4/DMI sheep in Exp. 1 (P < 0.05). Enteric CH4 emissions were numerically 8% less (P = 0.15) in Exp.1 and 10% less (P = 0.004) in Exp. 2 and total animal level GHG emissions (CH4 and N2O) were numerically 7% less (P = 0.21) in Exp. 1 and 8% less (P = 0.006) in Exp.2 for progeny of the low compared to the high CH4/DMI line sheep. In conclusion, the magnitude of difference in enteric CH4 (expressed as CO2-equivalent) between low and high CH4/DMI selection line sheep were still present when CH4 from faeces and N2O emissions from urine and faeces were also accounted for. The animal genetic traits were expressed independent of environmental factors, i.e. pasture quality and season.

Nutrition and food security impacts of quality seeds of biofortified orange-fleshed sweetpotato: Quasi-experimental evidence from Tanzania
Shikuku, Kelvin Mashisia ; Okello, Julius Juma ; Wambugu, Stella ; Sindi, Kirimi ; Low, J.W. ; McEwan, Margaret - \ 2019
World Development 124 (2019). - ISSN 0305-750X
Biofortified sweetpotato - Nutrition and food security impacts - Orange-fleshed sweetpotato - Quasi-field experiment - Tanzania - Virus-free

This study examined the nutrition and food security impacts of a project that was designed to improve availability of disease-free planting materials of biofortified orange-fleshed sweetpotato (OFSP) in rural Tanzania. Difference-in-difference and matching techniques were employed to estimate causal effects using panel data. Participation in the project increased agronomic and nutritional knowledge of households, raised uptake rate for OFSP varieties, and improved food security status. Effects on nutrition are, however, weak. These results suggest that timely access to quality seeds accompanied by a transfer of skills is important to reduce barriers to adoption of biofortified crops with resulting positive effects on the welfare of rural households. Adequate promotion of both agronomic and nutrition aspects of the technologies may enhance nutrition effects.

Characterisation of the effect of day length, and associated differences in dietary intake, on the gut microbiota of Soay sheep
Thomas, Nadine A. ; Olvera-Ramírez, Andrea M. ; Abecia, Leticia ; Adam, Clare L. ; Edwards, Joan E. ; Cox, Georgina F. ; Findlay, Patricia A. ; Destables, Elodie ; Wood, Tracy A. ; McEwan, Neil R. - \ 2019
Archives of Microbiology 201 (2019)7. - ISSN 0302-8933 - p. 889 - 896.
Anaerobic fungi - Bacteria - Ciliated protozoa - Day length - Digestive tract - Soay sheep

Differences in the rumen bacterial community have been previously reported for Soay sheep housed under different day length conditions. This study extends this previous investigation to other organs of the digestive tract, as well as the analysis of ciliated protozoa and anaerobic fungi. The detectable concentrations of ciliated protozoa and anaerobic fungi decreased with increased day length in both the rumen and large colon, unlike those of bacteria where no effect was observed. Conversely, bacterial community composition was affected by day length in both the rumen and large colon, but the community composition of the detectable ciliated protozoa and anaerobic fungi was not affected. Day length-associated differences in the bacterial community composition extended to all of the organs examined, with the exception of the duodenum and the jejunum. It is proposed that differences in rumen fill and ruminal ‘by-pass’ nutrients together with endocrinological changes cause the observed effects of day length on the different gut microbial communities.

Efficiency of insect-proof net tunnels in reducing virus-related seed degeneration in sweet potato
Ogero, K.O. ; Kreuze, J.F. ; McEwan, M.A. ; Luambano, N.D. ; Bachwenkizi, H. ; Garrett, K.A. ; Andersen, K.F. ; Thomas-Sharma, S. ; Vlugt, R.A.A. van der - \ 2019
Plant Pathology 68 (2019)8. - ISSN 0032-0862 - p. 1472 - 1480.
farmer-multiplier - modelling - net tunnels - seed - sweet potato - virus-related degeneration

Virus-related degeneration constrains production of quality sweet potato seed, especially under open field conditions. Once in the open, virus-indexed seed is prone to virus infection leading to decline in performance. Insect-proof net tunnels have been proven to reduce virus infection under researcher management. However, their effectiveness under farmer-multiplier management is not known. This study investigated the ability of net tunnels to reduce degeneration in sweet potato under farmer-multiplier management. Infection and degeneration were assessed for two cultivars, Kabode and Polista, grown in net tunnels and open fields at two sites with varying virus pressures. There was zero virus incidence at both sites during the first five generations. Sweet potato feathery mottle virus and sweet potato chlorotic stunt virus were present in the last three generations, occurring singly or in combination to form sweet potato virus disease. Virus infection increased successively, with higher incidences recorded at the high virus pressure site. Seed degeneration modelling illustrated that for both varieties, degeneration was reduced by the maintenance of vines under net tunnel conditions. The time series of likely degeneration based on a generic model of yield loss suggested that, under the conditions experienced during the experimental period, infection and losses within the net tunnels would be limited. By comparison, in the open field most of the yield could be lost after a small number of generations without the input of seed with lower disease incidence. Adopting the technology at the farmer-multiplier level can increase availability of clean seed, particularly in high virus pressure areas.

Small food texture modifications can be used to change oral processing behaviour and to control ad libitum food intake
Mosca, Ana Carolina ; Pohlenz Torres, Armando ; Slob, Evalien ; Graaf, Kees de; McEwan, Jean A. ; Stieger, Markus - \ 2019
Appetite 142 (2019). - ISSN 0195-6663
Eating rate - Food intake - Food texture - Oral processing behaviour - Satiation

Little is known whether small modifications of food texture are sufficient to influence satiation. This study used four iso-caloric yogurts differing in viscosity (low/high) and granola particle size (small/large) to investigate the influence of small texture modifications on oral processing behaviour, eating rate and ad libitum intake. Yogurt viscosity differed by a factor of 1.57x to 1.81x. Granola particle size was 6 mm and 12 mm (2-fold difference). Granola particle concentration based on weight was constant (15% w/w). Oral processing behaviour was quantified by video recording consumers eating yogurt ad libitum (n = 104). Ratings for appetite, liking and product familiarity were also quantified. A decrease in yogurt viscosity significantly decreased spoon size, number of chews per spoon and oral exposure time per spoon but did not significantly affect eating rate and ad libitum intake. A decrease in granola particle size from 12 mm to 6 mm at constant weight concentration significantly increased number of chews per spoon and decreased spoon size, eating rate and ad libitum intake without affecting liking. The differences in eating rate and ad libitum intake between yogurts containing small and large granola particles were 5 g/min (7%) and 17 g (5%), respectively. We suggest that the volume of granola particles added to the yogurt and not the size of particles per se was the driver of oral processing behaviour. We conclude that relatively small modifications in yogurt texture, especially granola particle size, are sufficient to change oral processing behaviour and ad libitum intake. These findings demonstrate that small texture modifications of foods, such as the size of granola particles added to yogurt, can be used to modulate eating rate and food intake within a meal.

Why interventions in the seed systems of roots, tubers and bananas crops do not reach their full potential
Almekinders, Conny J.M. ; Walsh, Steve ; Jacobsen, Kim S. ; Andrade-Piedra, Jorge L. ; McEwan, Margaret A. ; Haan, Stef de; Kumar, Lava ; Staver, Charles - \ 2019
Food Security 11 (2019)1. - ISSN 1876-4517 - p. 23 - 42.
Decentralized multipliers - Farmer demand - Seed quality - Vegetative multiplication

Seed systems for roots, tuber, and banana (RTB) crops receive relatively little attention from development-oriented research and commercial seed sector actors, despite their importance for food security, nutrition and rural livelihoods. We review RTB seed systems—with particular reference to potato, sweetpotato, cassava, yam and banana —to reflect on current seed system development approaches and the unique nature of these systems. We refer to our own experiences, literature and 13 case studies of RTB seed system interventions to identify gaps in our knowledge on farmer practices in sourcing and multiplying seed, and processes affecting seed quality. Currently, most approaches to developing RTB seed systems favour decentralised multiplication models to make quality seed available to smallholder farmers. Nevertheless, arguments and experiences show that in many situations, the economic sustainability of these models cannot be guaranteed, among others because the effective demand of farmers for seed from vegetatively propagated crops is unclear. Despite the understudied nature of farmers’ agronomic and social practices in relation to seed production and sourcing in RTB crops, there is sufficient evidence to show that local RTB seed systems are adaptive and dynamic. Our analysis suggests the paramount importance of understanding farmers’ effective demand for seed and how this affects the sustainable supply of quality seed from specialized producer-entrepreneurs, regardless of the seed system paradigm. From the case studies we learnt that few interventions are designed with a rigorous understanding of these issues; in particular, what types of interventions work for which actors, where, and why, although this is a necessary condition for prioritizing investments to increase the use of improved seed by smallholder farmers.

Effect of Farmers’ Multidimensional Beliefs on Adoption of Biofortified Crops : Evidence from Sweetpotato Farmers in Tanzania
Shikuku, Kelvin Mashisia ; Okello, Julius Juma ; Sindi, Kirimi ; Low, Jan W. ; Mcewan, Margaret - \ 2019
Journal of Development Studies 55 (2019)2. - ISSN 0022-0388 - p. 227 - 242.
We examined the effect of multidimensional farmers’ beliefs on the likelihood of cultivating planting materials of biofortified orange-fleshed sweetpotato (OFSP) varieties. Using a panel dataset and combining difference-in-differences regression with propensity score matching, results showed positive effects of beliefs related to health benefits, yielding ability, sweetness, disease-resistance, storability, early maturity, colour, and that children enjoy eating OFSP roots, on cultivation of OFSP varieties. The proportion of OFSP roots out of total sweetpotato production for a household increased among farmers’ who held these beliefs. Efforts to promote biofortified crops can, therefore, benefit from taking farmers’ multidimensional beliefs into consideration.
Addressing global ruminant agricultural challenges through understanding the rumen microbiome : Past, present, and future
Huws, Sharon A. ; Creevey, Christopher J. ; Oyama, Linda B. ; Mizrahi, Itzhak ; Denman, Stuart E. ; Popova, Milka ; Muñoz-Tamayo, Rafael ; Forano, Evelyne ; Waters, Sinead M. ; Hess, Matthias ; Tapio, Ilma ; Smidt, Hauke ; Krizsan, Sophie J. ; Yáñez-Ruiz, David R. ; Belanche, Alejandro ; Guan, Leluo ; Gruninger, Robert J. ; McAllister, Tim A. ; Newbold, C.J. ; Roehe, Rainer ; Dewhurst, Richard J. ; Snelling, Tim J. ; Watson, Mick ; Suen, Garret ; Hart, Elizabeth H. ; Kingston-Smith, Alison H. ; Scollan, Nigel D. ; Prado, Rodolpho M. Do; Pilau, Eduardo J. ; Mantovani, Hilario C. ; Attwood, Graeme T. ; Edwards, Joan E. ; McEwan, Neil R. ; Morrisson, Steven ; Mayorga, Olga L. ; Elliott, Christopher ; Morgavi, Diego P. - \ 2018
Frontiers in Microbiology 9 (2018)SEP. - ISSN 1664-302X
Diet - Host - Methane - Microbiome - Omics - Production - Rumen

The rumen is a complex ecosystem composed of anaerobic bacteria, protozoa, fungi, methanogenic archaea and phages. These microbes interact closely to breakdown plant material that cannot be digested by humans, whilst providing metabolic energy to the host and, in the case of archaea, producing methane. Consequently, ruminants produce meat and milk, which are rich in high-quality protein, vitamins and minerals, and therefore contribute to food security. As the world population is predicted to reach approximately 9.7 billion by 2050, an increase in ruminant production to satisfy global protein demand is necessary, despite limited land availability, and whilst ensuring environmental impact is minimized. Although challenging, these goals can be met, but depend on our understanding of the rumen microbiome. Attempts to manipulate the rumen microbiome to benefit global agricultural challenges have been ongoing for decades with limited success, mostly due to the lack of a detailed understanding of this microbiome and our limited ability to culture most of these microbes outside the rumen. The potential to manipulate the rumen microbiome and meet global livestock challenges through animal breeding and introduction of dietary interventions during early life have recently emerged as promising new technologies. Our inability to phenotype ruminants in a high-throughput manner has also hampered progress, although the recent increase in "omic" data may allow further development of mathematical models and rumen microbial gene biomarkers as proxies. Advances in computational tools, high-throughput sequencing technologies and cultivation-independent "omics" approaches continue to revolutionize our understanding of the rumen microbiome. This will ultimately provide the knowledge framework needed to solve current and future ruminant livestock challenges.

Understanding root, tuber, and banana seed systems and coordination breakdown : a multi-stakeholder framework
Bentley, Jeffery W. ; Andrade-Piedra, Jorge ; Demo, Paul ; Dzomeku, Beloved ; Jacobsen, Kim ; Kikulwe, Enoch ; Kromann, Peter ; Kumar, P.L. ; McEwan, Margaret ; Mudege, Netsayi ; Ogero, Kwame ; Okechukwu, Richardson ; Orrego, Ricardo ; Ospina, Bernardo ; Sperling, Louise ; Walsh, Stephen ; Thiele, Graham - \ 2018
Journal of Crop Improvement 32 (2018)5. - ISSN 1542-7528 - p. 599 - 621.
Bananas and plantains - root crops - seed security - seed systems - tuber crops - vegetatively propagated crops (VPC)

Vegetatively propagated crop (VPC) seed tends to remain true to varietal type but is bulky, often carries disease, and is slow to produce. So VPC seed needs to be handled differently than that of other crops, e.g., it tends to be sourced locally, often must be fresh, and it is less often sold on the market. Hence, a framework was adapted to describe and support interventions in such seed systems. The framework was used with 13 case studies to understand VPC seed systems for roots, tubers, and bananas, including differing roles and sometimes conflicting goals of stakeholders, and to identify potential coordination breakdowns when actors fail to develop a shared understanding and vision. In this article, we review those case studies. The framework is a critical tool to (a) document VPC seed systems and build evidence; (b) diagnose and treat coordination breakdown and (c) guide decision-makers and donors on the design of more sustainable seed system interventions for VPCs. The framework can be used to analyze past interventions and will be useful for planning future VPC seed programs.

Specialised sweetpotato vine multiplication in lake zone, Tanzania : What “sticks” and what changes?
McEwan, Margaret A. ; Lusheshanija, Dorothy ; Shikuku, Kelvin M. ; Sindi, Kirimi - \ 2017
Open Agriculture 2 (2017)1. - ISSN 2391-9531 - p. 64 - 69.
Adaptation - Scaling-up - Seed enterprise - Skilling - Specialisation - Sweetpotato vine multipliers - Training
In Lake Zone, Tanzania, farmers were trained to multiply and distribute quality sweetpotato planting material. The objectives of this study were to assess changes in skills and practices among the trained farmers as vine multiplication became a specialized task. Nine months after the project ended, all 88 decentralized vine multipliers (DVMs) operating as groups (72%) or individuals (28%) were visited and qualitative data on their current multiplication practices collected through a questionnaire, checklists and observations. Results showed that 69% of DVMs were still multiplying vines, but less than half were using the seed production technologies promoted by the project. 34% used rapid multiplication beds; 61% used conventional plant spacing on ridges for roots and vines and 5% used both. As the vine multiplication cycle became a specialised activity, the multiplication and root production cycles were separated. Vines were treated differently in terms of site selection, length of cutting and spacing, depending on whether the objective of their use was for high root or high vine production. Capacity building of specialised vine multipliers and scaling-up seed interventions should consider the implications of skilling and task segregation in a broader context based on society's choice of technologies and agrarian change.
Fungal baits offer hope for spotted-wing Drosophila biological control
Tol, Rob van - \ 2016

An insect-devouring fungus shows promise in the control of spotted-wing Drosophila, a pest of soft fruit, according to Dutch researchers.

Can small still be beautiful? Moving local sweetpotato seed systems to scale in sub-Saharan Africa.
McEwan, M. ; Almekinders, C.J.M. ; Abidin, C. - \ 2015
In: Potato and Sweetpotato in Africa / Low, J., Nyongesa, M., Quinn, S., Parker, M., CABI - ISBN 9781780644202 - p. 289 - 310.
In sub-Saharan Africa (SSA), a range of farmer-based practices for the conservation and multiplication of sweetpotato planting material has evolved. In bimodal rainfall areas, sequential planting ensures that a ware crop is in the ground for most of the year, and vines are harvested from one crop to plant the next one. In unimodal areas with a long dry season, practices include the use of 'volunteer' planting material from sprouting roots which have been left in the ground from the previous crop. The predominant sources of planting material are from the farmer's own field or from friends or neighbours. However, these practices result in limited amounts of planting material being available at the start of the rains and contribute to the build-up of pests and diseases contributing to suboptimal root crop production. Sweetpotato breeding efforts are leading to the development of new varieties that are preferred by farmers and consumers. However, without strong linkages to seed multiplication and dissemination efforts these varieties may not quickly benefit large numbers of smallholder farmers and consumers. Increasingly there are specialized vine multipliers who have been supported by 'project' interventions. Yet, it is not clear whether and how these interventions have built on the successful elements of existing practices. Our chapter examines the literature on local seed system functioning, and the implications for crops such as sweetpotato. The chapter reviews recent efforts to multiply and disseminate sweetpotato planting material in Mozambique, Uganda, Tanzania, Malawi, Ethiopia and West Africa. New varieties and technologies have been promoted together with interventions to 'engineer' changes in the organization and coordination of the seed system. We review the country cases to gauge the extent to which successful elements of farmer-based practices for managing sweetpotato planting material have been identified and built into the process of redesigning the seed system. A number of issues are identified for discussion. These include: (i) What are the critical points for interaction between the traditional farmer-based practices and the formal seed system?; (ii) What are the trade-offs between remaining local, and yet achieving scale?; and (iii) How can the quality of planting material be assured as we go to scale? We also assess the different drivers for the seed system, and the implications for the functions of various stakeholders and patterns of communication and coordination. The chapter concludes by highlighting gaps in our current understanding for getting sweetpotato seed systems not only moving, but working at scale.
Coordinated international action to accelerate genome-to-phenome with FAANG, the Functional Annotation of Animal Genomes project : open letter
Archibald, A.L. ; Bottema, C.D. ; Brauning, R. ; Burgess, S.C. ; Burt, D.W. ; Casas, E. ; Cheng, H.H. ; Clarke, L. ; Couldrey, C. ; Dalrymple, B.P. ; Elsik, C.G. ; Foissac, S. ; Giuffra, E. ; Groenen, M.A.M. ; Hayes, B.J. ; Huang, L.S. ; Khatib, H. ; Kijas, J.W. ; Kim, H. ; Lunney, J.K. ; McCarthy, F.M. ; McEwan, J. ; Moore, S. ; Nanduri, B. ; Notredame, C. ; Palti, Y. ; Plastow, G.S. ; Reecy, J.M. ; Rohrer, G. ; Sarropoulou, E. ; Schmidt, C.J. ; Silverstein, J. ; Tellam, R.L. ; Tixier-Boichard, M. ; Tosser-klopp, G. ; Tuggle, C.K. ; Vilkki, J. ; White, S.N. ; Zhao, S. ; Zhou, H. - \ 2015
Genome Biology 16 (2015). - ISSN 1474-7596 - 6 p.
We describe the organization of a nascent international effort, the Functional Annotation of Animal Genomes (FAANG) project, whose aim is to produce comprehensive maps of functional elements in the genomes of domesticated animal species.
Animal board Invited Review: Genetic possibilities to reduce enteric methane emissions from ruminants
Pickering, N.K. ; Oddy, V.H. ; Basarab, J. ; Cammack, K. ; Hayes, B. ; Hegarty, R. ; Lassen, J. ; McEwan, J. ; Miller, S. ; Pinares-Patino, C. ; Haas, Y. de - \ 2015
Animal 9 (2015)9. - ISSN 1751-7311 - p. 1431 - 1440.
special topics-mitigation - nitrous-oxide emissions - dairy-cows - genomic selection - sheep - rumen - fermentation - accuracy - cattle - livestock
Measuring and mitigating methane (CH4) emissions from livestock is of increasing importance for the environment and for policy making. Potentially, the most sustainable way of reducing enteric CH4 emission from ruminants is through the estimation of genomic breeding values to facilitate genetic selection. There is potential for adopting genetic selection and in the future genomic selection, for reduced CH4 emissions from ruminants. From this review it has been observed that both CH4 emissions and production (g/day) are a heritable and repeatable trait. CH4 emissions are strongly related to feed intake both in the short term (minutes to several hours) and over the medium term (days). When measured over the medium term, CH4 yield (MY, g CH4/kg dry matter intake) is a heritable and repeatable trait albeit with less genetic variation than for CH4 emissions. CH4 emissions of individual animals are moderately repeatable across diets, and across feeding levels, when measured in respiration chambers. Repeatability is lower when short term measurements are used, possibly due to variation in time and amount of feed ingested prior to the measurement. However, while repeated measurements add value; it is preferable the measures be separated by at least 3 to 14 days. This temporal separation of measurements needs to be investigated further. Given the above issue can be resolved, short term (over minutes to hours) measurements of CH4 emissions show promise, especially on systems where animals are fed ad libitum and frequency of meals is high. However, we believe that for short-term measurements to be useful for genetic evaluation, a number (between 3 and 20) of measurements will be required over an extended period of time (weeks to months). There are opportunities for using short-term measurements in standardised feeding situations such as breath 'sniffers' attached to milking parlours or total mixed ration feeding bins, to measure CH4. Genomic selection has the potential to reduce both CH4 emissions and MY, but measurements on thousands of individuals will be required. This includes the need for combined resources across countries in an international effort, emphasising the need to acknowledge the impact of animal and production systems on measurement of the CH4 trait during design of experiments.
Breeding Ruminants that Emit Less Methane – The Role of International Collaboration
Oddy, V.H. ; Haas, Y. de; Basarab, J. ; Cammack, K. ; Hayes, B.J. ; Hegarty, R. ; Lassen, J. ; McEwan, J. ; Miller, S. ; Pinares-Patino, C. - \ 2014
Ruminants contribute to global greenhouse gas (GHG) emissions, principally as enteric methane (CH4) emissions. Direct selection for reduced CH4 emissions through combined selection for both low residual feed intake and methane yield could potentially provide a long term reduction in enteric methane production of 40-45%. If a methane-related trait were to be implemented by a livestock industry it will most likely be via genomic breeding values, which demand large numbers of measured animals in the reference population. Given the size of the reference population required for methane traits, it is imperative that wherever possible groups around the world collaborate on methodologies for measurement and collection of data. This has been the primary focus of the Animal Selection Genetics and Genomics Network (ASGGN) of the Livestock Research Group of the Global Research Alliance to reduce GHG emissions from agriculture.
Consensus methods for breeding low methane emitting : Breeding ruminants that emit less methane - development of consensus methods for measurements of methane (white paper)
Pickering, N.K. ; Haas, Y. de; Basarab, J. ; Cammack, K. ; Hayes, B. ; Hegarty, R. ; Lassen, J. ; McEwan, J. ; Miller, S. ; Pinares-Patino, C. ; Shackell, G. ; Vercoe, P. ; Oddy, Hutton - \ 2013
ASGGN - 57
animal breeding - selection - animal genetics - genomics - methane - sheep - cattle - agriculture and environment - dierveredeling - selectie - diergenetica - genomica - methaan - schapen - rundvee - landbouw en milieu
This report was prepared by a working group of the Animal Selection, Genetics and Genomics Network (ASGGN) of the Global Research Alliance for reducing greenhouse gases from agriculture. It is a summary of published and yet to be published work. The purpose is to evaluate methods that are potentially useful for measuring CH4 emissions in individual animals so as to estimate genetic parameters and subsequently screen animals for use in selective breeding programs including its use in the development of genomic selection.
Lighting strategy delivers saving (interview with Tom Dueck)
McEwan, G. ; Dueck, T.A. - \ 2013
Hortweek.com
Reducing energy use - glasshouse innovations
McEwan, G. ; Hemming, S. ; Sonneveld, P.J. - \ 2011
Hortweek.com
Lighting up the future
McEwan, G. ; Kempkes, F.L.K. - \ 2009
Hortweek.com
The [FeFe] hydrogenase of Nyctotherus ovalis has a chimeric origin
Boxma, B. ; Ricard, G. ; Hoek, A.H.A.M. van; Severing, E. ; Moon-van der Staay, S.Y. ; Staay, G.W.M. van der; Alen, T.A. ; Graaf, R.M. de; Cremers, G. ; Kwantes, M. ; McEwan, N.R. ; Newbold, C.J. ; Jouany, J.P. ; Michalowski, T. ; Pristas, P. ; Huynen, M.A. ; Hackstein, J.H.P. - \ 2007
BMC Evolutionary Biology 7 (2007). - ISSN 1471-2148 - 12 p.
multiple sequence alignment - complex-i - phylogenetic analysis - eukaryotic evolution - iron hydrogenases - life-style - hydrogenosomes - mitochondria - protein - models
Background The hydrogenosomes of the anaerobic ciliate Nyctotherus ovalis show how mitochondria can evolve into hydrogenosomes because they possess a mitochondrial genome and parts of an electron-transport chain on the one hand, and a hydrogenase on the other hand. The hydrogenase permits direct reoxidation of NADH because it consists of a [FeFe] hydrogenase module that is fused to two modules, which are homologous to the 24 kDa and the 51 kDa subunits of a mitochondrial complex I. Results The [FeFe] hydrogenase belongs to a clade of hydrogenases that are different from well-known eukaryotic hydrogenases. The 24 kDa and the 51 kDa modules are most closely related to homologous modules that function in bacterial [NiFe] hydrogenases. Paralogous, mitochondrial 24 kDa and 51 kDa modules function in the mitochondrial complex I in N. ovalis. The different hydrogenase modules have been fused to form a polyprotein that is targeted into the hydrogenosome. Conclusion The hydrogenase and their associated modules have most likely been acquired by independent lateral gene transfer from different sources. This scenario for a concerted lateral gene transfer is in agreement with the evolution of the hydrogenosome from a genuine ciliate mitochondrion by evolutionary tinkering.
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