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See detailModuler l'âge d'abattage des poulets de chair: Quel impact sur la qualité organoleptique de la viande?
De Maeseneire, Coraline ULg; Sindic, Marianne ULg; Beckers, Yves ULg

Article for general public (2013)

Avec l’émergence des nouveaux modes de production alternatifs, pour la plupart associés à la production dite de « qualité différenciée », plusieurs souches de poulets de chair sont éligibles en pratique ... [more ▼]

Avec l’émergence des nouveaux modes de production alternatifs, pour la plupart associés à la production dite de « qualité différenciée », plusieurs souches de poulets de chair sont éligibles en pratique en Région wallonne. Ces souches se distinguent suivant de nombreux critères dont la durée du cycle nécessaire pour produire une carcasse commercialisable. Or l’âge à l’abattage influencerait fortement les qualités sensorielles de la viande de poulet. Une question essentielle se pose dès lors : quelle influence une modification de l’âge à l’abattage du poulet de chair peut-elle avoir sur la perception de la qualité de la viande par le consommateur ? [less ▲]

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See detailCattle methane fluxes measurement over an intensively grazed grassland using eddy covariance
Dumortier, Pierre ULg; Aubinet, Marc ULg; Beckers, Yves ULg et al

Poster (2013, September)

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions (European Commission, 2009). Recent technological advances in spectroscopy now ... [more ▼]

Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions (European Commission, 2009). Recent technological advances in spectroscopy now permit methane flux measurement using eddy covariance. This method has numerous strengths. It can measure fluxes in situ, continuously and across broad areas. This provides information about meadow and cattle emission behaviour throughout the year and across a broad range of climatic conditions. We will present here a one year monitoring of methane exchange between an intensively grazed meadow and the atmosphere obtained using the eddy-covariance method. Methane fluxes exchanged by a grazed meadow were measured continuously since June 2012 at the Dorinne Terrestrial Observatory (50˚ 18’ 44” N; 4˚ 58’ 07” E; 248 m asl.) in Belgium. The site is an intensively pastured meadow of 4.2 ha managed according to the regional common practices where up to 30 Belgian Blue cows are grazing simultaneously. Flux measurements were made with the eddy covariance technique, using a fast CH4 analyzer (Picarro G2311-f) and a sonic anemometer (Campbell Csat3). Carbon dioxide fluxes and various micro-meteorological and soil variables, biomass growth and stocking rate evolution were also measured at the site. Turbulent fluxes were calculated according to standard eddy covariance computation schemes and were filtered for non-stationarity and for low friction velocity (u*) events. During grazing periods, fluxes are dominated by the enteric fermentation source and average 111 nmol m-2 s-1. They are highly variable, probably due to cow movements in and out the measurement footprint and cow digestion rhythm. Despite this spread, a daily emission rhythm is observed with higher emissions during the afternoon. When fluxes are integrated over large periods, methane emissions were found strongly related to cattle stocking rate with a slope of 7.34±0.78 mol CH4 day-1 LSU-1. Further developments are ongoing in order to improve cattle geo-localization through infra-red cameras and individual home-made GPS devices. The two systems will be compared in terms of cost, efficiency and ease of use. During cow-free periods, the methane flux averages 10.5 nmol m-2 s-1 and is highly variable with some production peaks above 100 nmol m-2 s-1. No relation was found between methane fluxes and soil temperature while a weak negative relation was found between methane fluxes and soil humidity. No soil methane absorption has been observed. European Commission. Fifth National Communication from the European Community Under the UN Framework Convention on Climate Change (UNFCCC). Technical Report - 2009 – 038 (2009). [less ▲]

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See detailImpact of grazing on carbon dioxide flux exchanges in an intensively managed grassland
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2013, September)

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed ... [more ▼]

To date, there are few studies assessing the impact of specific management events, particularly grazing, on carbon (C) and carbon dioxide (CO2) fluxes in managed grasslands. Grazing effects are indeed difficult to discern. They vary with the stocking rate and the length of the grazing period. Moreover, they are often masked by environmental responses. The aim of the present study was to assess the impact of grazing on the CO2 fluxes of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne Terrestrial Observatory (DTO), located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). The site is a permanent grassland of ca. 4.2 ha subjected to intensive management. Grassland carbon budget at the system boundaries is calculated from Net Ecosystem Exchange of CO2 measured by eddy covariance by taking imports and exports of organic C and losses of carbon as methane into account. After 2 years of measurements, the site was close to equilibrium. If management practices (harvest, fertilization and imports as supplementary feedings) and climatic conditions had a significant impact on the C balance, the impact of grazing was uncertain, especially on CO2 fluxes. To do this analysis, we distinguished the long term and the short term impacts of grazing on CO2 fluxes. The long term effect results from the biomass consummation by the cattle and from the cattle effluents that modify assimilation and respiration fluxes. This could be quantified only by comparing fluxes before and after grazing periods. The short term impact is due to cattle respiration that is a part of total ecosystem respiration and should be measured in its presence in the field. For the long term effects of grazing on CO2 fluxes, we analyzed the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration normalized at 10°C (Rd,10). Those parameters were deduced from the response of daytime CO2 fluxes to radiation over 5-day windows. We calculated parameters variations between the beginning and the end of grazing and non-grazing periods (∆GPPmax, ∆Rd,10) and analyzed their dependence to stocking rate. We found a significant decreased of ∆GPPmax that allowed us to quantify the assimilation reduction due to grass consumption by cattle. Discrimination of this impact from flux response to climate was possible only after gathering and treating two years of measurements taken under various climatic conditions. At the opposite, no significant evolution of Rd,10 with the average stocking rate was found. The short term impacts were an increase of CO2 fluxes in presence of cattle. It could be distinguished and quantified only thanks to confinement experiments. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Livestock contribution to CO2 fluxes was estimated to be 2.25 ± 0.68 kg C LU-1 d-1. [less ▲]

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See detailHedges and woody strips browsing by cattle on pasture in Wallonia, Belgium
Vandermeulen, Sophie ULg; Pascal, Mathilde; Marche, Christian et al

in Michalk, David L.; Millar, Geoffrey D.; Badgery, Warwick B. (Eds.) et al Revitalising Grasslands to Sustain our Communities: Proceedings 22nd International Grassland Congress, Sydney 15-19 september 2013 (2013, September)

Agri-environmental measures promote woody hedges along meadows in Wallonia, raising the interest in tree and shrub as forage in intensive mixed dairy temperate production systems. This study aimed at (1 ... [more ▼]

Agri-environmental measures promote woody hedges along meadows in Wallonia, raising the interest in tree and shrub as forage in intensive mixed dairy temperate production systems. This study aimed at (1) determining the influence of an access to hedges on the grazing behavior of young cattle and (2) assessing the fermentation characteristics of woody species promoted in Wallonia. Twelve heifers, divided in two groups, were set to graze a ryegrass and white clover-based pasture in May 2012. The first group had access to a hedge composed of 12 temperate tree and shrub species, and the second group grazed the pasture only. The grazing and browsing behavior of the animals was recorded for 4 weeks along with pasture biomass availability, using the hand-plucking method. Samples of the 12 tree species were fermented using rumen fluid in an automated gas pressure monitoring system and gas production kinetics compared to ryegrass and white clover. Results suggest that the feeding behavior was influenced by the hedge. Grazing time of the control group was higher than heifers that could browse woody foliage (P<0.05). Browsing was especially noticeable when grass availability on pasture was lowest. In vitro ruminal fermentation kinetics differed among species (P<0.01) with Populus nigra and Fraxinus excelsior showing a potential of fermentation similar to herbaceous forages. It can be concluded that due to the browsing by cattle some woody species could be interesting as complementary feeding. Besides their attributes regarding the agricultural landscape, their feeding qualities should be considered when planting the hedges. [less ▲]

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See detailQuelle place pour la viande rouge dans nos assiettes ?
Beckers, Yves ULg

Conference given outside the academic context (2013)

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See detailTemporal variability of nitrous oxide fluxes from a fertilized grassland in Belgium: preliminary results from dynamic closed chambers.
Beekkerk van Ruth, Jöran ULg; Moureaux, Christine ULg; Degré, Aurore ULg et al

Poster (2013, April 09)

Presentation of preliminary results from N2O measurements over a grassland using dynamic closed chambers. See attached folders for more detail.

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See detailImpact of grazing on carbon balance of an intensively grazed grassland in Belgium
Jerome, Elisabeth ULg; Beckers, Yves ULg; Beekkerk van Ruth, Jöran ULg et al

Poster (2013, April 09)

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The ... [more ▼]

This work analyzes the impact of grazing on the carbon balance of a grassland grazed by the Belgian Blue breed of cattle. The research was run at the Dorinne terrestrial observatory (DTO). The experimental site is a permanent grassland of ca. 4.2 ha located in the Belgian Condroz (50° 18’ 44’’ N; 4° 58’ 07’’ E; 248 m asl.). Other studies are conducted at the DTO including measurements of methane (CH4) and nitrous oxide fluxes (Dumortier et al., Geophysical Research Abstracts, Vol. 15, EGU2013-2083-1, 2013; Beekkerk van Ruth et al., Geophysical Research Abstracts, Vol. 15, EGU2013-3211, 2013, respectively). Grassland carbon budget (Net Biome Productivity, NBP) was calculated from Net Ecosystem Exchange (NEE) measured by eddy covariance by taking imports and exports of organic C and losses of carbon as CH4 into account (Soussana et al., 2010). After 2 years of measurements (May 2010 - May 2012), the grassland behaved on average as a CO2 source (NEE = 73 ±31 g C m-2 y-1). After inclusion of all the C inputs and outputs the site was closed to equilibrium (NBP = 23 ±34 g C m-2 y-1). To analyze the impact of grazing on CO2 fluxes, we studied the temporal evolution of gross maximal photosynthetic capacity GPPmax and dark respiration Rd (deduced from the response of daytime fluxes to radiation over 5-day windows). We calculated GPPmax and Rd variation between the end and the beginning of grazing or non-grazing periods (∆GPPmax and ∆Rd, respectively). We observed a significant decrease of GPPmax during grazing periods and measured a ∆GPPmax dependence on the average stocking rate. This allows us to quantify the assimilation reduction due to grass consumption by cattle. On the contrary, no Rd decrease was observed during grazing periods. Moreover, we found that cumulated monthly NEE increased significantly with the average stocking rate. In addition, a confinement experiment was carried out in order to analyze livestock contribution to Total Ecosystem Respiration. Each experiment extended over two days: the first day, cattle was confined in the footprint of the eddy covariance set-up (1.76 ha, 27 LU ha-1) and the second day, it was removed from it. We compared filtered half-hourly data made at 24h intervals, in the presence or absence of cattle, considering that environmental conditions were equivalent (air temperature, wind speed, radiation and wind direction). Results showed that CO2 fluxes were significantly higher when cattle were on the plot. Livestock contribution estimation to CO2 fluxes was on average 6.6 µmol m-2 s-1. [less ▲]

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See detailAlimentation azotée des animaux de rente
Beckers, Yves ULg

Learning material (2013)

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See detailEvaluation du troisième Programme de Gestion Durable de l'Azote en agriculture. Recommandations en matière de règlementations et de recherches scientifiques
Vandenberghe, Christophe ULg; Destain, Jean-Pierre ULg; Beckers, Yves ULg et al

in Vandenberghe, Christophe; Colinet, Gilles; Destain, Jean-Pierre (Eds.) et al 2ème Atelier Nitrate - Eau. Evaluation du Programme de Gestion Durable de l'Azote (2013)

In accordance with the Nitrates Directive, the third “Durable Nitrogen Management Plan” (PGDA) will be soon reviewed in Wallonia (Belgium). The second “Nitrate – Water” workshop took place between 28th ... [more ▼]

In accordance with the Nitrates Directive, the third “Durable Nitrogen Management Plan” (PGDA) will be soon reviewed in Wallonia (Belgium). The second “Nitrate – Water” workshop took place between 28th May and 1st June 2012. The workshop was attended by both Belgian scientists (Université catholique de Louvain - UCL, Walloon Agricultural Research Center CRA-W, Université de Liège - ULg, Gembloux Agro-Bio Tech) and French scientists (National Institute for Agricultural Research - INRA). In the light of the results of experiments presented by scientists at this workshop, modifications to the PGDA are now recommended. These concern organic and mineral nitrogen fertilization for crops and meadows; catch crops; soil nitrate-nitrogen residue limitation in autumn, at the start of the nitrate leaching period; the management of meadow ploughing and a modification of the dairy cow standard for nitrogen production. [less ▲]

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See detailValorisation de l'épeautre dans l'alimentation des bovins
Beckers, Yves ULg

Scientific conference (2013, March 19)

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See detailLes légumineuses comme source protéique dans la ration des ruminants
Beckers, Yves ULg

Conference given outside the academic context (2013)

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See detailD31-1254: Influence de l'âge et du poids d'abattage sur la qualité organoleptique du poulet de chair à croissance lente en Région wallonne (Rapport final).
De Maeseneire, Coraline ULg; Beckers, Yves ULg; Thewis, André ULg

Report (2013)

Ces dernières années, la progression de la production avicole en Wallonie est, en grande partie, liée au développement de filières dites de qualité différenciée. En 2009, ce sont près de 2.000.000 de ... [more ▼]

Ces dernières années, la progression de la production avicole en Wallonie est, en grande partie, liée au développement de filières dites de qualité différenciée. En 2009, ce sont près de 2.000.000 de poulets qui ont été associés à ce type de production. Cependant, contrairement au poulet standard pour lesquels les pratiques sont très standardisées, les pratiques d’élevage en qualité différenciée peuvent varier, notamment la génétique, l’âge et le poids à l’abattage, le sexe de l’animal, l’accès à un parcours… Ces variations peuvent influencer l’homogénéité de la qualité organoleptique de la viande de poulet au sein d’une même filière ainsi que la perception (et la confiance) des consommateurs vis-à-vis de la viande des poulets qui en sont issus. L’objectif de ce projet est d’étudier et d’objectiver de manière scientifique la qualité organoleptique de la viande de poulet de chair au sein de trois filières avicoles de qualité différenciée afin de fournir aux détenteurs de ces filières des informations quant aux facteurs susceptibles de modifier la qualité organoleptique de leurs produits ainsi que la perception de ceux-ci par les consommateurs. [less ▲]

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See detailLes productions fourragères en intercultures : quel potentiel pour l'alimentation des bovins en système allaitant ?
Beckers, Yves ULg

Conference given outside the academic context (2013)

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See detailElevage et gaz à effet de serre : le bilan des émissions de l'animal à la filière
Dumortier, Pierre ULg; Rabier, Fabienne; Beckers, Yves ULg et al

Scientific conference (2013, February 20)

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See detailQuelle place pour la viande rouge dans nos assiettes ?
Beckers, Yves ULg

Conference given outside the academic context (2013)

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