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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    We will mail you new results for this query: keywords==Productivity
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Effects of condensed tannins on live weight, faecal nitrogen and blood metabolites of free-ranging female goats in a semi-arid African savanna
Mkhize, N.R. ; Heitkӧnig, I.M.A. ; Scogings, P.F. ; Dziba, L.E. ; Prins, H.H.T. ; Boer, W.F. de - \ 2018
Small Ruminant Research 166 (2018). - ISSN 0921-4488 - p. 28 - 34.
Growth - Mixed-feeder - Polyethylene glycol - Productivity - Ruminant

Current understanding of the effects of condensed tannins (CTs) on productivity of mixed-feeding ruminants is largely based on simple laboratory and feeding experiments. These experiments do not allow mixed feeders such as goats to adequately employ their behavioural and physiological responses to plant secondary metabolites. In a field experiment, we investigated the effects of CTs on growth performance of goats. We hypothesized that CTs reduce blood circulatory nutrient and increase nitrogen in faeces. We divided 45 yearling females into three groups of 15 animals that were orally dosed daily with either CTs, polyethylene glycol 6000 (PEG, a polymer that neutralizes dietary tannins), or water (control). We measured the average daily gains, live weights, faecal nitrogen and four blood metabolites from each goat during dry and wet seasons. Live weights increased over time in both dry (P < 0.001) and wet seasons (P < 0.001). The average daily gain was consistently greatest for animals dosed with PEG and least for those dosed with CTs. Goats dosed with CTs had the greatest faecal nitrogen and the least blood protein concentrations, while the opposite was true for PEG goats in both seasons. Blood urea and non-esterified fatty acids indicated a negative influence of CTs on energy and protein metabolism. We concluded that CTs limit growth and PEG mitigates the negative effects of CTs on growth performance of free-ranging mixed feeding ruminants.

Unravelling variation in feeding, social interaction and growth patterns among pigs using an agent-based model
Boumans, Iris J.M.M. ; Boer, Imke J.M. de; Hofstede, Gert Jan ; Bokkers, Eddie A.M. - \ 2018
Physiology and Behavior 191 (2018). - ISSN 0031-9384 - p. 100 - 115.
Animal welfare - Feeding behaviour - Group dynamics - Growing pigs - Productivity - Simulation
Domesticated pigs, Sus scrofa, vary considerably in feeding, social interaction and growth patterns. This variation originates partly from genetic variation that affects physiological factors and partly from behavioural strategies (avoid or approach) in competitive food resource situations. Currently, it is unknown how variation in physiological factors and in behavioural strategies among animals contributes to variation in feeding, social interaction and growth patterns in animals. The aim of this study was to unravel causation of variation in these patterns among pigs. We used an agent-based model to explore the effects of physiological factors and behavioural strategies in pigs on variation in feeding, social interaction and growth patterns. Model results show that variation in feeding, social interaction and growth patterns are caused partly by chance, such as time effects and coincidence of conflicts. Furthermore, results show that seemingly contradictory empirical findings in literature can be explained by variation in pig characteristics (i.e. growth potential, positive feedback, dominance, and coping style). Growth potential mainly affected feeding and growth patterns, whereas positive feedback, dominance and coping style affected feeding patterns, social interaction patterns, as well as growth patterns. Variation in behavioural strategies among pigs can reduce aggression at group level, but also make some pigs more susceptible to social constraints inhibiting them from feeding when they want to, especially low-ranking pigs and pigs with a passive coping style. Variation in feeding patterns, such as feeding rate or meal frequency, can indicate social constraints. Feeding patterns, however, can say something different about social constraints at group versus individual level. A combination of feeding patterns, such as a decreased feed intake, an increased feeding rate, and an increased meal frequency might, therefore, be needed to measure social constraints at individual level.
Species and structural diversity affect growth of oak, but not pine, in uneven-aged mature forests
Vanhellemont, Margot ; Bijlsma, Rienk Jan ; Keersmaeker, Luc De; Vandekerkhove, Kris ; Verheyen, Kris - \ 2018
Basic and Applied Ecology 27 (2018). - ISSN 1439-1791 - p. 41 - 50.
Biodiversity - Ecosystem functioning - Pinus sylvestris - Productivity - Quercus petraea - Quercus robur - Temperate forest
The effects of mixing tree species on tree growth and stand production have been abundantly studied, mostly looking at tree species diversity effects while controlling for stand density and structure. Regarding the shift towards managing forests as complex adaptive systems, we also need insight into the effects of structural diversity. Strict forest reserves, left for spontaneous development, offer unique opportunities for studying the effects of diversity in tree species and stand structure. We used data from repeated inventories in ten forest reserves in the Netherlands and northern Belgium to study the growth of pine and oak. We investigated whether the diversity of a tree's local neighbourhood (i.e., species and structural diversity) is important in explaining its basal area growth. For the subcanopy oak trees, we found a negative effect of the tree species richness of the local neighbours, which - in the studied forests - was closely related to the share of shade-casting tree species in the neighbourhood. The growth of the taller oak trees was positively affected by the height diversity of the neighbour trees. Pine tree growth showed no relation with neighbourhood diversity. Tree growth decreased with neighbourhood density for both species (although no significant relationship was found for the small pines). We found no overall diversity-growth relationship in the studied uneven-aged mature forests; the relationship depended on tree species identity and the aspect of diversity considered (species vs. structural diversity).
Plant-Soil Feedback : Bridging Natural and Agricultural Sciences
Mariotte, Pierre ; Mehrabi, Zia ; Bezemer, T.M. ; Deyn, Gerlinde B. De; Kulmatiski, Andrew ; Drigo, Barbara ; Veen, G.F. ; Heijden, Marcel G.A. van der; Kardol, Paul - \ 2018
Trends in Ecology and Evolution 33 (2018)2. - ISSN 0169-5347 - p. 129 - 142.
Biodiversity conservation - Climate change - Crop rotation - Plant root traits - Productivity - Sustainability
In agricultural and natural systems researchers have demonstrated large effects of plant-soil feedback (PSF) on plant growth. However, the concepts and approaches used in these two types of systems have developed, for the most part, independently. Here, we present a conceptual framework that integrates knowledge and approaches from these two contrasting systems. We use this integrated framework to demonstrate (i) how knowledge from complex natural systems can be used to increase agricultural resource-use efficiency and productivity and (ii) how research in agricultural systems can be used to test hypotheses and approaches developed in natural systems. Using this framework, we discuss avenues for new research toward an ecologically sustainable and climate-smart future.
Species and soil effects on overyielding of tree species mixtures in the Netherlands
Lu, Huicui ; Condés, Sonia ; Río, Miren del; Goudiaby, Venceslas ; Ouden, Jan den; Mohren, Godefridus M.J. ; Schelhaas, Mart Jan ; Waal, Rein de; Sterck, Frank J. - \ 2018
Forest Ecology and Management 409 (2018). - ISSN 0378-1127 - p. 105 - 118.
Niche complementarity - Productivity - Soil - Species mixing effect - Volume growth

A growing number of studies provides evidence that mixed-species forests often have higher stand productivity than monospecific forests, which is referred to as overyielding. In this study, we explored how the combination of species and soil conditions affect overyielding in terms of periodic annual volume increment (PAIV) in Dutch forests. We studied Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), common beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), pedunculate oak (Quercus robur L.), and silver birch (Betula pendula Roth) growing in four two species combinations (Douglas-fir–common beech, Scots pine–pedunculate oak, pedunculate oak–common beech, and pedunculate oak–silver birch) from 398 long-term permanent field plots all over the Netherlands. We found that the Douglas-fir–common beech and Scots pine–pedunculate oak mixtures always showed overyielding. This overyielding was largely attributed to the Douglas-fir in the former mixture and to the pedunculate oak in the latter mixture, respectively. In both cases, overyielding was stronger at poor soils than at rich soils. The pedunculate oak–common beech mixtures overyielded at poor soils and underyielded at rich soils, which was attributed to the response of the common beech. Overyielding was not observed for the pedunculate oak–silver birch mixtures, irrespective of soil conditions. The results do not support our hypothesis since overyielding was not always driven by fast-growing light-demanding species. Overyielding was stronger for evergreen–deciduous species combinations, suggesting that differences in leaf phenology are a major driver of overyielding. Secondly, our results imply that overyielding is much stronger at poor soils than at rich soils, which is in line with the prediction of the stress-gradient hypothesis. We conclude that the growth of one species benefits from the admixture species, particularly in evergreen–deciduous species mixtures and that soils affect the extent of overyielding as studied in the Netherlands.

Extending miscanthus cultivation with novel germplasm at six contrasting sites
Kalinina, Olena ; Nunn, Christopher ; Sanderson, Ruth ; Hastings, Astley F.S. ; Weijde, Tim van der; Özgüven, Mensure ; Tarakanov, Ivan ; Schüle, Heinrich ; Trindade, Luisa M. ; Dolstra, Oene ; Schwarz, Kai Uwe ; Iqbal, Yasir ; Kiesel, Andreas ; Mos, Michal ; Lewandowski, Iris ; Clifton-Brown, John C. - \ 2017
Frontiers in Plant Science 8 (2017). - ISSN 1664-462X
Establishment - Marginal land - Miscanthus - Multi-location field trials - Novel hybrids - Productivity

Miscanthus is a genus of perennial rhizomatous grasses with C4 photosynthesis which is indigenous in a wide geographic range of Asian climates. The sterile clone, Miscanthus × giganteus (M. × giganteus), is a naturally occurring interspecific hybrid that has been used commercially in Europe for biomass production for over a decade. Although, M. × giganteus has many outstanding performance characteristics including high yields and low nutrient offtakes, commercial expansion is limited by cloning rates, slow establishment to a mature yield, frost, and drought resistance. In this paper, we evaluate the performance of 13 novel germplasm types alongside M. × giganteus and horticultural “Goliath” in trials in six sites (in Germany, Russia, The Netherlands, Turkey, UK, and Ukraine). Mean annual yields across all the sites and genotypes increased from 2.3 ± 0.2 t dry matter ha−1 following the first year of growth, to 7.3 ± 0.3, 9.5 ± 0.3, and 10.5 ± 0.2 t dry matter ha−1 following the second, third, and fourth years, respectively. The highest average annual yields across locations and four growth seasons were observed for M. × giganteus (9.9 ± 0.7 t dry matter ha−1) and interspecies hybrid OPM-6 (9.4 ± 0.6 t dry matter ha−1). The best of the new hybrid genotypes yielded similarly to M. × giganteus at most of the locations. Significant effects of the year of growth, location, species, genotype, and interplay between these factors have been observed demonstrating strong genotype × environment interactions. The highest yields were recorded in Ukraine. Time needed for the crop establishment varied depending on climate: in colder climates such as Russia the crop has not achieved its peak yield by the fourth year, whereas in the hot climate of Turkey and under irrigation the yields were already high in the first growing season. We have identified several alternatives to M. × giganteus which have provided stable yields across wide climatic ranges, mostly interspecies hybrids, and also Miscanthus genotypes providing high biomass yields at specific geographic locations. Seed-propagated interspecific and intraspecific hybrids, with high stable yields and cheaper reliable scalable establishment remain a key strategic objective for breeders.

Agricultural Co-Operatives in Ethiopia : Evolution, Functions and Impact
Tefera, Delelegne A. ; Bijman, Jos ; Slingerland, Maja A. - \ 2017
Journal of International Development 29 (2017)4. - ISSN 0954-1748 - p. 431 - 453.
Agricultural co-operatives - Ethiopia - Market access - Productivity - Public investment - Transaction costs
To what extent can co-operatives strengthen rural development in sub-Saharan Africa? This paper explores the development of agricultural co-operatives in Ethiopia, particularly the changes in economic functions. Co-operative development in Ethiopia has been strongly influenced by various political regimes. Based on expert interviews and a literature review, we explore the factors that influence a shift in economic functions from provision of inputs to commercialization of farm products. Our review shows that the impact of commercialization on farmer welfare is still inconclusive. Both the institutional environment and the internal governance structure have a hard time adjusting to changing economic conditions.
The evolutionary legacy of diversification predicts ecosystem function
Yguel, Benjamin ; Jactel, Hervé ; Pearse, Ian S. ; Moen, Daniel ; Winter, Marten ; Hortal, Joaquin ; Helmus, Matthew R. ; Kühn, Ingolf ; Pavoine, Sandrine ; Purschke, Oliver ; Weiher, Evan ; Violle, Cyrille ; Ozinga, Wim ; Brändle, Martin ; Bartish, Igor ; Prinzing, Andreas - \ 2016
American Naturalist 188 (2016)4. - ISSN 0003-0147 - p. 398 - 410.
Community ecology - Evolutionary history - Lineage-throughtime plots - Phylogenetic diversity - Productivity - Species coexistence

Theory suggests that the structure of evolutionary history represented in a species community may affect its functioning, but phylogenetic diversity metrics do not allow for the identification of major differences in this structure. Here we propose a new metric, ELDERness (for Evolutionary Legacy of DivERsity) to estimate evolutionary branching patterns within communities by fitting a polynomial function to lineage-through-time (LTT) plots. We illustrate how real and simulated community branching patterns can be more correctly described by ELDERness and can successfully predict ecosystem functioning. In particular, the evolutionary history of branching patterns can be encapsulated by the parameters of third-order polynomial functions and further measured through only two parameters, the “ELDERness surfaces.” These parameters captured variation in productivity of a grassland community better than existing phylogenetic diversity or diversification metrics and independent of species richness or presence of nitrogen fixers. Specifically, communitieswith small ELDERness surfaces (constant accumulation of lineages through time in LTT plots) were more productive, consistent with increased productivity resulting from complementary lineages combined with niche filling within lineages. Overall, while existing phylogenetic diversity metrics remain useful in many contexts, we suggest that our ELDERness approach better enables testing hypotheses that relate complex patterns of macroevolutionary history represented in local communities to ecosystem functioning.

Climate change mitigation and productivity gains in livestock supply chains : insights from regional case studies
Mottet, Anne ; Henderson, Benjamin ; Opio, Carolyn ; Falcucci, Alessandra ; Tempio, Giuseppe ; Silvestri, Silvia ; Chesterman, Sabrina ; Gerber, Pierre J. - \ 2016
Regional Environmental Change (2016). - ISSN 1436-3798 - 13 p.
Climate change - Livestock systems - Mitigation - Packages of options - Productivity

Livestock can contribute to climate change mitigation by reducing their greenhouse gas emissions and by increasing soil carbon sequestration. Packages of mitigation techniques can bring large environmental benefits as illustrated in six case studies modeled in the Global Livestock Environmental Assessment Model developed by FAO. With feasible technical interventions in livestock production systems, the mitigation potential of each of the selected species, systems and regions ranges from 14 to 41 %. While comparably high mitigation potentials were estimated for ruminant and pig production systems in Asia, Latin America and Africa, large emission reductions can also be attained in dairy systems with already high levels of productivity, in OECD countries. Mitigation interventions can lead to a concomitant reduction in emissions and increase in production, contributing to food security. This is particularly the case for improved feeding practices and better health and herd management practices. Livestock systems also have a significant potential for sequestrating carbon in pasturelands and rangelands through improved management, as illustrated in two of the six case studies in this paper.

Effective lactation yield : A measure to compare milk yield between cows with different dry period lengths
Kok, Akke ; Middelaar, C.E. van; Engel, B. ; Knegsel, A.T.M. van; Hogeveen, H. ; Kemp, B. ; Boer, I.J.M. de - \ 2016
Journal of Dairy Science 99 (2016). - ISSN 0022-0302 - p. 2956 - 2966.
Calving interval - Dry period length - Milk yield - Productivity

To compare milk yields between cows or management strategies, lactations are traditionally standardized to 305-d yields. The 305-d yield, however, gives no insight into the combined effect of additional milk yield before calving, decreased milk yield after calving, and a possible shorter calving interval in the case of a shortened dry period. We aimed to develop a measure that would enable the comparison of milk yield between cows with different dry period (DP) lengths. We assessed the importance of accounting for additional milk yield before calving and for differences in calving interval. The 305-d yield was compared with a 365-d yield, which included additional milk yield in the 60 d before calving. Next, an effective lactation yield was computed, defined as the daily yield from 60 d before calving to 60 d before the next calving, to account for additional milk yield before calving and for differences in calving interval. Test-day records and drying-off dates of 15 commercial farms were used to compute the 305-d, 365-d, and effective lactation yields for individual cows. We analyzed 817 second-parity lactations preceded by no DP, a short DP (20 to 40 d), or a conventional DP (49 to 90 d). Compared with cows with a conventional DP, the 305-d yield of cows with no DP was 7.0 kg of fat- and protein-corrected milk (FPCM) per day lower, and the 305-d yield of cows with a short DP was 2.3 kg of FPCM per day lower. Including additional milk yield before calving in the 365-d yield reduced this difference to 3.4 kg of FPCM per cow per day for cows with no DP and to 0.9 kg of FPCM per cow per day for cows with a short DP. Compared with cows with a conventional DP, median days open were reduced by 25 d for cows with no DP and by 18 d for cows with a short DP. Accounting for these differences in calving interval in the effective lactation yield further decreased yield reductions for cows with no DP or a short DP by 0.3 kg of FPCM per cow per day. At the herd level, estimated 365-d yield losses for cows with no DP or a short DP differed from effective lactation yield losses by 0.4 to -0.8 kg FPCM per cow per day. Accounting for additional milk yield before calving had a major and consistent effect on yield comparisons of cows with different DP lengths. The effect of correcting for calving interval was more variable between farms and will especially be important when calving interval is affected by DP length.

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