References of "Dufrasne, Isabelle"
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See detailPrediction of test-day body weight from dairy cow characteristics and milk spectra
Soyeurt, Hélène ULiege; Colinet, Frédéric ULiege; Froidmont, E. et al

in Book of Abstracts of the 69th Annual Meeting of the European Federation of Animal Science (2018, August)

The knowledge of individual body weight (BW) is a management key in terms of feed efficiency and to assess the environmental footprint of dairy production. From 6 farms, BW were measured on 735 Holstein ... [more ▼]

The knowledge of individual body weight (BW) is a management key in terms of feed efficiency and to assess the environmental footprint of dairy production. From 6 farms, BW were measured on 735 Holstein cows. Daily milk samples were collected on these weighed cows and analysed by mid-infrared spectrometry. The stage and number of lactation were also collated. A spectral cleaning was conducted by calculating GH distances from 17 principal components. Spectra with a GH greater than 3 were discarded. The final dataset contained 720 records. Predicting equations were based on Partial Least Squares regressions. Cross-validation coefficient of determination (R2cv) and root mean square error (RMSEPcv) of the equation including only spectral data were of 0.19 and 65 kg. Then, days in milk, month of test and lactation stage were added. The obtained R2cv and RMSEPcv increased (0.43 and 54 kg). The part of the information derived from the spectral data was equal to 6%. By adding the daily milk yield, the BW prediction was slightly improved and showed a R2cv of 0.45 and a RMSEPcv of 53 kg. The use of Legendre Polynomials to regress the spectral data following the day in milk did not improve the predictability. By deleting samples showing a squared residual higher than its mean + 3 times of its standard deviation, the final equation included 668 samples (93% of the initial set) and had a R2cv of 0.58 and RMSEPcv of 42 kg. A herd cross-validation was then performed to assess the robustness of the developed equation. RMSEPv ranged from 40 to 58 kg. This preliminary study showed the potentiality to predict an indicator of body weight. As this prediction uses easy to record explicative variables and if a larger validation confirmed the obtained results, this prediction equation could be used to develop large scale study about feed efficiency. Moreover, this method allows to consider the past information if spectral data are available. [less ▲]

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See detailGrazing practices in three European countries: results of a survey in dairy farms
Lessire, Françoise ULiege; Scohier, Catherine; Kristensen, Troels et al

in Sustainable meat and milk production from grassalnds (2018, June 17)

Grassland plays an important role in mitigation of greenhouse gases (GHG) emissions from the agricultural sector by sinking carbon (Soussana et al., 2010). Thus grazing is often essential for maintenance ... [more ▼]

Grassland plays an important role in mitigation of greenhouse gases (GHG) emissions from the agricultural sector by sinking carbon (Soussana et al., 2010). Thus grazing is often essential for maintenance of grassland. Furthermore grazing has demonstrated positive effects on animal welfare, production costs, landscape and biodiversity. However grazing is decreasing in most European countries. For the project Life Dairyclim, a survey was led in the three partner countries for a better understanding of grazing practices and of perceptions and expectations of dairy farmers. A questionnaire was thus sent in dairy farms of South-Belgium (BE), Luxembourg (LU) and Denmark (DK). From 1439 filled forms, 1147 declared that lactating cows grazed (80%) but this result reflects different situations: 95% LC were grazing in BE while this percentage dropped to 83% in LU and 37% in DK. This lower % of LC seemed to be linked to larger farm surface, bigger herd size and increased milk yield. The opinion about benefits of grazing depended on the grazing practices. Grazing farmers were very convinced about beneficial effects of grazing on animal welfare (95.4%) and on landscape preservation (86.1%). Surprisingly the positive effect on environment was mentioned in only 61.3% forms and even a negative impact was cited in 16.6%. Eighty six % of surveyed farmers expected to continue grazing. [less ▲]

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See detailMethane emissions and milk carbon footprint of dairy cows at grazing or fed with a concentrate diet
Lessire, Françoise ULiege; Scohier, Catherine; Dufrasne, Isabelle ULiege

in Sustainable meat and milk production from grassalnds (2018, June 17)

In order to compare methane emissions and carbon footprint of milk produced by dairy cows with different feeding strategies, a trial was carried out on 2 groups of 11 Holstein cows from May to July 2017 ... [more ▼]

In order to compare methane emissions and carbon footprint of milk produced by dairy cows with different feeding strategies, a trial was carried out on 2 groups of 11 Holstein cows from May to July 2017. One group was grazing day and night with a target sward availability of 17 kg per cow. The other one received a diet composed of dried pellets mixed with straw, molasses and alfalfa hay. In the barn where all the cows had permanent access, an automatic concentrate supplier provided concentrates to complement the ration of both groups. Methane emissions were assessed by predictions based on the mid infra-red spectra of milk samples and by the Guardian® located in the automatic concentrate supplier. Furthermore, ruminal fluid was sampled monthly on 5 cows of each group to check the ruminal function (pH, redox potential, presence and mobility of protozoa). The aim of this study was to get a holistic overview of the effect of contrasted feeding practices on methane emissions, environmental impact, zootechnical and economical performances. Grazing decreased feeding costs and feeding environmental impacts while methane emissions per kg milk increased. This highlights the complexity of mitigation actions of GHG in the dairy sector. [less ▲]

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See detailCombiner robot de traite et pâturage
Lessire, Françoise ULiege; Dufrasne, Isabelle ULiege

Article for general public (2017)

La traite robotisée s'impose de plus en plus dans les exploitations laitières avec pour corollaire la diminution du pâturage. Pourtant cette pratique est bénéfique au niveau économique et environnemental ... [more ▼]

La traite robotisée s'impose de plus en plus dans les exploitations laitières avec pour corollaire la diminution du pâturage. Pourtant cette pratique est bénéfique au niveau économique et environnemental ainsi que du point de vue du bien-être animal. Mais est-ce possible de concilier robot de traite et pâturage? C'est la question à laquelle le projet Européen Autograssmilk a tenté de répondre. [less ▲]

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See detailImpact of grazing practices on farm self-sufficiency, milk and economic performances of three automatized farms
Lessire, Françoise ULiege; Scohier, Catherine ULiege; Dufrasne, Isabelle ULiege

in Porqueddu, Claudio; Franca, Antonello; Lombardi, Giampiero (Eds.) et al Grassland resources for extensive farming systems in marginal lands: major drivers and future scenarios (2017, May 07)

The dairy sector is facing serious economic difficulties linked to low milk price and volatility of feedstuff price. In this context, reducing farm inputs is necessary. Optimization of use of grazed ... [more ▼]

The dairy sector is facing serious economic difficulties linked to low milk price and volatility of feedstuff price. In this context, reducing farm inputs is necessary. Optimization of use of grazed, ensiled or dried grass could be a key strategy to improve self-sufficiency and thus to decrease feeding costs. Yet, practice of grazing is disappearing due to several factors, including increased size of dairy herds and development of automation. However combining grazing and automatic milking systems (AMS) is possible. Three Walloon dairy farms equipped with an AMS were monitored to assess their grazing practices, grass proportion in the cows’ diet both at barn and on pasture and the economic advantages linked to grass use in 2015. These farms practiced various grazing strategies including full-grass system (FG), day and night grass allocation (DNG), and rotational grazing (RG) completed with a partial mixed ration. The effects of grazing on milk yield (MY) were also evaluated. Grazing reduced the daily feeding costs per cow in all systems with variable impact due to grazing management. The most pronounced decline was observed in FG with a severe drop in MY. Conversely, the decrease in MY was less marked in the other farms. [less ▲]

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See detailThe effect of concentrate allocation on traffic and milk production of pasture based cows milked by an automatic milking system
Lessire, Françoise ULiege; Froidmont, Eric; Shortall, John et al

in Animal (2017), 11(4), 1-9

Increased economic, societal and environmental challenges facing agriculture are leading to a greater focus on effective way to combine grazing and automatic milking systems (AMS). One of the fundamental ... [more ▼]

Increased economic, societal and environmental challenges facing agriculture are leading to a greater focus on effective way to combine grazing and automatic milking systems (AMS). One of the fundamental aspects of robotic milking is cows’ traffic to the AMS. Numerous studies have identified feed provided, either as fresh grass or concentrate supplement, as the main incentive for cows to return to the robot. The aim of this study was to determine the effect of concentrate allocation on voluntary cow traffic from pasture to the robot during the grazing period, to highlight the interactions between grazed pasture and concentrate allocation in terms of substitution rate and the subsequent effect on average milk yield and composition. Thus, 29 grazing cows, milked by a mobile robot, were monitored for the grazing period (4 months). They were assigned to 2 groups: a low concentrate (LC) group (15 cows) and a high concentrate (HC) group (14 cows) receiving 2 kg and 4 kg concentrate per cow per day respectively. Two allocations per day of fresh pasture were provided at 0700h and 1600h. The cows had to go through the AMS to receive the fresh pasture allocation. The effect of concentrate level on robot visitation was calculated by summing milkings, refusals and failed milkings/cow per day. The impact on average daily milk yield and composition was also determined. The interaction between lactation number and month was used as an indicator of pasture availability. Concentrate allocation increased significantly robot visitations in HC (3.60 ± 0.07 visitations/cow per day in HC - 3.10 ± 0.07 visitations/cow per day in LC; P<0.001) while milkings/cow per day were similar in both groups (LC: 2.37 ± 0.02/day - HC: 2.39 ± 0.02/day; ns). The average daily milk yield over the grazing period was enhanced in HC (22.39 ± 0.22 kg/cow per day in HC- 21.33 ± 0.22 kg/cow per day in LC; P<0.001). However the gain in milk due to higher concentrate supply was limited with regards to the amount of provided concentrates. Milking frequency in HC primiparous compared with LC was increased. In the context of this study, considering high concentrate levels as an incentive for robot visitation might be questioned, as it had no impact on milking frequency and limited impact on average milk yield and composition. By contrast, increased concentrate supply could be targeted specifically to primiparous cows. [less ▲]

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See detailEnquête sur les pratiques de pâturage en Wallonie: Résultats et conclusions
Lessire, Françoise ULiege; Dufrasne, Isabelle ULiege

Conference given outside the academic context (2017)

The role of grasslands as a C sink is generally accepted. It is considered that permanent grasslands allow annual C storage rates between 22 and 44 g C/m2/y (Soussana et al., 2010) thereby contributing to ... [more ▼]

The role of grasslands as a C sink is generally accepted. It is considered that permanent grasslands allow annual C storage rates between 22 and 44 g C/m2/y (Soussana et al., 2010) thereby contributing to the mitigation of greenhouse gas (GHG) emissions. Grassland preservation has several other advantages including a decrease in feeding costs (Dillon et al., 2005), a positive effect on cows’ health (e.g.a decrease in lameness) (Burow et al., 2011) and the provision of a positive image to consumers. Despite these arguments, grazing is decreasing in Europe and grasslands are disappearing. A better understanding of grazing practices and of farmers’ expectations could suggest ways of improving these practices and limiting grassland disappearance. As a result, Walloon dairy farmers were surveyed in December 2015 and the preliminary results are presented below. [less ▲]

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See detailPâturer avec un robot de traite: une diversité de stratégies...
Brocard, Valérie; Lessire, Françoise ULiege; Cloet, Estelle et al

in Fourrages (2017), 229

Au cours du projet Autograssmilk, différentes stratégies ont été testées pour maximiser la production de lait ( et réduire les coûts alimentaires) en combinant robot et pâturage dans une large gamme de ... [more ▼]

Au cours du projet Autograssmilk, différentes stratégies ont été testées pour maximiser la production de lait ( et réduire les coûts alimentaires) en combinant robot et pâturage dans une large gamme de contextes: des systèmes pâturants à faibles coûts alimentaires, jusqu'à des systèmes plus intensifs tournés vers la recherche de productivité animale. Ainsi, les points-clés de la réussite d'un système combinant robot de traite et pâturage ont pu être décrits, notamment pour le choix d'un mode de gestion de l'alimentation (et son adaptation aux variations d'herbe disponible), la circulation des vaches (selon le nombre de vaches traites par robot), la distance des parcelles (possibilité d'utiliser un robot déplaçable). Les animaux ont la faculté de s'habituer à un nouveau mode de fonctionnement. [less ▲]

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See detailTraite robotisée, grands troupeaux et pâturage: retour d'expérience de 2 exploitations en Belgique
Lessire, Françoise ULiege; Knoden, David; Dufrasne, Isabelle ULiege

in Fourrages (2017), 229

La technique de traite robotisée entraîne dans bon nombre de cas l’abandon du pâturage ou, du moins, une forte diminution de la part d’herbe pâturée dans la ration des vaches laitières. Cet article montre ... [more ▼]

La technique de traite robotisée entraîne dans bon nombre de cas l’abandon du pâturage ou, du moins, une forte diminution de la part d’herbe pâturée dans la ration des vaches laitières. Cet article montre qu’il est possible de concilier traite robotisée, pâturage et grands troupeaux tout en gardant de bonnes performances économiques. [less ▲]

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See detailEvaluation of the ruminal function of Belgian dairy cows suspected of subacute ruminal acidosis.
Lessire, Françoise ULiege; Knapp, Emilie; Theron, Léonard et al

in Vlaams Diergeneeskundig Tijdschrift (2017), 86(1), 16-23

Subacute ruminal acidosis (SARA) has been considered a major pathology in high producing dairy herds for years. These findings were corroborated by several studies in Europe. However, different feeding ... [more ▼]

Subacute ruminal acidosis (SARA) has been considered a major pathology in high producing dairy herds for years. These findings were corroborated by several studies in Europe. However, different feeding practices and herds’ production levels are found in Southern Belgium. This study aimed to ascertain whether dairy cows of several herds from the south of Belgium (Wallonia) with a suspicion of SARA really did present too low ruminal pH values. Twenty-four herds were visited and 172 cows were sampled using an oropharyngeal device to collect ruminal fluid, i.e. Geishauser probe. On the samples, three tests were performed: pH measurement, methylene blue reduction test and microscopic evaluation of protozoa vitality. Based on these analyses, no cows demonstrated pH values lower than 5.5 and, only ten cows could be considered at risk for SARA. By contrast, in eightteen cows, pH values higher than 7.0 were measured and ruminal inactivity was suspected. In this study, ruminal alkalosis appeared to be more frequently observed than SARA. [less ▲]

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See detailDevelopment of an open-source algorithm based on inertial measurement units (IMU) of a smartphone to detect cattle grass intake and ruminating behaviors
Andriamandroso, Andriamasinoro ULiege; Lebeau, Frédéric ULiege; Beckers, Yves ULiege et al

in Computers and Electronics in Agriculture (2017), 139

In this paper, an open algorithm was developed for the detection of cattle’s grass intake and rumination activities. This was done using the widely available inertial measurement unit (IMU) from a ... [more ▼]

In this paper, an open algorithm was developed for the detection of cattle’s grass intake and rumination activities. This was done using the widely available inertial measurement unit (IMU) from a smartphone, which contains an accelerometer, a gyroscope, a magnetometer and location sensors signals sampled at 100 Hz. This equipment was mounted on 19 grazing cows of different breeds and daily video sequences were recorded on pasture of different forage allowances. After visually analyzing the cows’ movements on a calibration database, signal combinations were selected and thresholds were determined based on 1-s time windows, since increasing the time window did not increase the accuracy of detection. The final algorithm uses the average value and standard deviation of two signals in a two-step discrimination tree: the gravitational acceleration on x-axis (Gx) expressing the cows’ head movements and the rotation rate on the same x-axis (Rx) expressing jaw movements. Threshold values encompassing 95% of the normalized calibrated data gave the best results. Validation on an independent database resulted in an average detection accuracy of 92% with a better detection for rumination (95%) than for grass intake (91%). The detection algorithm also allows for characterization of the diurnal feeding activities of cattle at pasture. Any user can make further improvements, for data collected at the same way as the iPhone’s IMU has done, since the algorithm codes are open and provided as supplementary data. [less ▲]

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See detailChallenges and priorities for modelling livestock health and pathogens in the context of climate change
Özkan, Şeyda; Vitali, Andrea; Lacetera, Nicola et al

in Environmental Research (2016), 151(Supplement C), 130-144

Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role ... [more ▼]

Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role in assessing the impacts of climate change on livestock systems and the efficacy of potential adaptation strategies, to support decision making for more efficient, resilient and sustainable production. However, a coherent set of challenges and research priorities for modelling livestock health and pathogens under climate change has not previously been available. To identify such challenges and priorities, researchers from across Europe were engaged in a horizon-scanning study, involving workshop and questionnaire based exercises and focussed literature reviews. Eighteen key challenges were identified and grouped into six categories based on subject-specific and capacity building requirements. Across a number of challenges, the need for inventories relating model types to different applications (e.g. the pathogen species, region, scale of focus and purpose to which they can be applied) was identified, in order to identify gaps in capability in relation to the impacts of climate change on animal health. The need for collaboration and learning across disciplines was highlighted in several challenges, e.g. to better understand and model complex ecological interactions between pathogens, vectors, wildlife hosts and livestock in the context of climate change. Collaboration between socio-economic and biophysical disciplines was seen as important for better engagement with stakeholders and for improved modelling of the costs and benefits of poor livestock health. The need for more comprehensive validation of empirical relationships, for harmonising terminology and measurements, and for building capacity for under-researched nations, systems and health problems indicated the importance of joined up approaches across nations. The challenges and priorities identified can help focus the development of modelling capacity and future research structures in this vital field. Well-funded networks capable of managing the long-term development of shared resources are required in order to create a cohesive modelling community equipped to tackle the complex challenges of climate change. [less ▲]

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See detailEnquête sur l’évolution des surfaces agricoles dédiées aux prairies et sur la proportion des prairies pâturées en Belgique, au Luxembourg et au Danemark
Lessire, Françoise ULiege; Dufrasne, Isabelle ULiege

Report (2016)

The role of grasslands in climate change is important as they are generally considered contributing to GHG mitigation by playing a role of carbon sink (Soussana et al., 2010). The mitigation potential of ... [more ▼]

The role of grasslands in climate change is important as they are generally considered contributing to GHG mitigation by playing a role of carbon sink (Soussana et al., 2010). The mitigation potential of grassland could be influenced by type of grassland, utilization including grazing intensity and rotational use of pastures. Furthermore, grazing has demonstrated several advantages as improving animal welfare (Burow et al., 2011), decreasing production costs (Dillon et al., 2005), preserving the landscape and the biodiversity (EAA, 2016) or having a good image on the consumer (De Olde et al., 2016). It seemed thus useful to survey the dairy sector of the three countries to get an overview of the dairy farms, the role of grassland and grazing practices, of the perceptions and of the expectations of the farmers about grazing. It was the aim of this report. [less ▲]

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See detailLife-Dairyclim, European project aiming to mitigate methane emissions and carbon footprint of dairy cows
Lessire, Françoise ULiege; Bernard, Maxime; Reding, Romain et al

in Höglind, Mats; Bakken, Anne Kjersti; Hovstad, Knut Anders (Eds.) et al The multiple roles of grassland in the European bioeconomy (2016, September 04)

How can dairy farming contribute to reduce the climate change without compromising food security and farm economy? This is the question the project Life-Dairyclim wants to answer. The project gathers ... [more ▼]

How can dairy farming contribute to reduce the climate change without compromising food security and farm economy? This is the question the project Life-Dairyclim wants to answer. The project gathers partners from research groups, association of advisory services to farmers and feed industry in collaboration with private farmers in three countries (Belgium, Luxembourg and Denmark). It focuses on production of feed, including utilisation of grassland and feeding of dairy cows in order to implement strategies that can contribute to a sustainable development of the dairy sector. Feeding experiments to decrease methane from dairy cows will be assessed at the University of Liège (Belgium) with cows milked by an automatic milking system. Methane production will be analysed individually by a device (Guardian®) inserted in the feeding bin as well as by mid infrared spectrum analysis of milk. The effect of concentrate composition on methane production during grazing in combination with optimization of grazing practices will be studied in collaboration with the industrial partner, Dumoulin (Belgium). The carbon footprint of produced milk will be determined using lifecycle assessment methods based on input from the experiments in combination with effect of feed production on especially carbon sequestration from different type of crop and utilization by Aarhus University (Denmark) and Convis, association of advisory services to farmers (Luxembourg). An important part of the project is dissemination based on pilot farms in all three countries documenting the impact of mitigation strategies adopted during the project [less ▲]

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See detailSelenium in Cattle: A Review
Mehdi, Youcef ULiege; Dufrasne, Isabelle ULiege

in Molecules (2016), 21(4), 545

This review article examines the role of selenium (Se) and the effects of Se supplementation especially in the bovine species. Selenium is an important trace element in cattle. Some of its roles include ... [more ▼]

This review article examines the role of selenium (Se) and the effects of Se supplementation especially in the bovine species. Selenium is an important trace element in cattle. Some of its roles include the participation in the antioxidant defense the cattle farms. The nutritional requirements of Se in cattle are estimated at 100 μg/kg DM (dry matter) for beef cattle and at 300 μg/kg DM for dairy cows. The rations high in fermentable carbohydrates, nitrates, sulfates, calcium or hydrogen cyanide negatively influence the organism’s use of the selenium contained in the diet. The Se supplementation may reduce the incidence of metritis and ovarian cysts during the postpartum period. The increase in fertility when adding Se is attributed to the reduction of the embryonic death during the first month of gestation. A use of organic Se in feed would provide a better transfer of Se in calves relative to mineral Se supplementation. The addition of Se yeasts in the foodstuffs of cows significantly increases the Se content and the percentage of polyunsaturated fatty acids (PUFA) in milk compared to the addition of sodium selenite. The enzyme 5-iodothyronine deiodinase is a seleno-dependent selenoprotein. It is one of the last proteins to be affected in the event of Se deficiency. This delay in response could explain the fact that several studies did not show the effect of Se supplementation on growth and weight gain of calves. Enrichment of Se in the diet did not significantly affect the slaughter weight and carcass yield of bulls. The impact and results of Se supplementation in cattle depend on physiological stage, Se status of animals, type and content of Se and types of Se administration. Further studies in Se supplementation should investigate the speciation of Se in food and yeasts, as well as understanding their metabolism and absorption. This constitute a path to exploit in order to explain certain different effects of Se. [less ▲]

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See detailEstimation de la quantité de matière sèche ingérée par les vaches laitières au pâturage en traite robotisée, utilisation de l’analyse des fèces en spectrométrie dans le proche infrarouge
Lessire, Françoise ULiege; Dufrasne, Isabelle ULiege; Decruyenaere, Virginie

in Agabriel, Jacques; Boichard, Didier; Choisis, Jean-Philippe (Eds.) et al 22èmes Rencontres autour des recherches sur les ruminants. (2015, December 02)

Malgré l’intérêt nutritionnel et économique de l’herbe dans la ration des vaches laitières, le pâturage est de plus en plus délaissé en raison notamment de l’automatisation de la traite et de l’extension ... [more ▼]

Malgré l’intérêt nutritionnel et économique de l’herbe dans la ration des vaches laitières, le pâturage est de plus en plus délaissé en raison notamment de l’automatisation de la traite et de l’extension de la taille des troupeaux. Une des raisons invoquées par les éleveurs pour cet abandon est leur manque de confiance par rapport aux quantités d’herbe réellement ingérées par les animaux et la crainte que ces apports inconstants se traduisent par des fluctuations de production laitière tant qualitative que quantitative. Or Decruyenaere et al. (2009, 2012) ont développé une méthode d’estimation de la matière sèche volontairement ingérée (MSVI) par analyse des bouses par spectrométrie dans le proche infra-rouge. Cette méthode présente l’avantage d’être non invasive, facile à mettre en œuvre sur le terrain et peu onéreuse. Le but de cette étude était donc d’évaluer l’utilisation de cette méthode dans un troupeau de vaches laitières traites par un robot mobile en pâture. Le troupeau (n=53) était divisé en 2 groupes dont le niveau de complémentation journalière était différent. Lors de la traite, le groupe 1 (GR1) recevait en moyenne 2,6 kg de concentrés/vache alors que le groupe 2 (GR2) en recevait 4,2 kg/vache. L’objectif était de vérifier l’impact du niveau de complémentation sur les résultats obtenus. Des prélèvements de fèces ont été faits une fois par mois sur 10 vaches (5 vaches par groupe) pendant 4 mois. Les spectres d’absorption dans le proche infra-rouge (NIR) ont été confrontés à des étalonnages NIR permettant l’estimation de la MSVI exprimée soit par rapport au poids vif (MSVI1), soit par rapport au poids métabolique (MSVI2). Ces estimations d’ingestion ont permis le calcul de la matière sèche journalière ingérée par vache (MSI1 et MSI2). Par ailleurs, les mesures d’herbe à l’entrée et à la sortie des parcelles pâturées ont été relevées ainsi que la densité du couvert herbacé pour évaluer la quantité d’herbe disponible. A ces valeurs de biomasses disponibles ont été additionnées des quantités de concentrés distribuées lors du passage des animaux au robot. Les valeurs moyennes de matière sèche ingérée (kg/vache/jour) pour le GR1 étaient de 15,20 ± 2,60 kg MS par la MSI1 et de 16,99 ± 1,80 kg MS pour la MSI2. Pour le GR2, la MSI1moyenne était de 20,20 ± 4,95 kg MS et la MSI2 moyenne de 21,95 ± 3,36 kg MS. L’estimation de la ration disponible par vache (kg MS herbe + kg MS concentrés) était de 17,25 ± 0,73 kg MS pour le GR1 et de 18,69 ±0,83 kg MS pour le GR2. Les valeurs obtenues par l’analyse NIR sont donc compatibles avec les quantités d’herbe et de concentrés disponibles. Les valeurs estimées par les 2 méthodes étaient hautement corrélées entre elles à part en période de faible ingestion (<10 kgMS). En ce cas la MSI2 semble donner des résultats plus fiables. En conclusion, l’analyse NIR des bouses apparaît une technique intéressante pour l’estimation de la quantité d’herbe ingérée au pâturage. [less ▲]

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See detailMilk production, milking frequency and rumination time of grazing dairy cows milked by a mobile milking robot.
Lessire, Françoise ULiege; Hornick, Jean-Luc ULiege; Minet, Julien ULiege et al

in Conington, J; Klopcic, M; Lauridsen, C (Eds.) et al Book of abstracts of the 66th Annual meeting of the European Federation of animal science (2015, September 28)

In Europe, analysis of meteorological data shows that the average temperature has increased by ~1°C over the past hundred years (IPCC, 2013). Heat stress periods are thus expected to be more frequent even ... [more ▼]

In Europe, analysis of meteorological data shows that the average temperature has increased by ~1°C over the past hundred years (IPCC, 2013). Heat stress periods are thus expected to be more frequent even in temperate areas. The use of an automatic milking system (AMS) implies the need to stimulate cows’ traffic to the robot, especially with grazing cows. Describing how heat stress influenced cows’ traffic to the robot is the aim of this study. Grazing dairy cows milked by an automatic system (AMS) experienced heat stress (HS) periods, twice during the summer 2013 in July (J) and August (A). The daily temperature humidity index (THI) during these periods were higher than 75. Each HS period was compared with a “normal period”(N), presenting the same number of cows, similar lactation number, days in milk, distance to come back to the robot and an equal access to water. The first HS period of 5 days with a mean THI of 78.4 was chosen in J, and a second that lasted for 6 days in A with a THI value of 77.3. Heat stress periods were cut off with the same duration of days with no stress (N) and mean THI <70. Milk production, milkings and refusals to the robot during HS were compared with N periods. Milkings and refusals were significantly more numerous in HS periods in July (HS: 2.54 ± 0.11 vs N: 2.19 ± 0.08, 1.87 ± 0.20 vs 0.72 ± 0.16) but milk production dropped from 21.8 ±0.6 kg per cow and per day during N periods to 18.9 ± 0.8 kg in HS. In August, MY increased slightly during HS. This could be explained by less high ambient temperatures and decreased distance to walk inducing less energy expenditure. The increase in milkings and refusals to the robot during HS could be linked to water availability nearby the robot and confirmed previous findings (Lessire et al., 2014). [less ▲]

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See detailChallenging land fragmentation thanks a mobile milking robot: Statement of 2 cases of implementation: Liège and Trevarez experimental farms
Brocard, Valérie; Dufrasne, Isabelle ULiege; Lessire, Françoise ULiege et al

in Conington, J; Klopcic, M; Lauridsen, C (Eds.) et al Book of abstracts of the 66th annual meeting of the European Federation of Animal Science (2015, September)

Cette présentation fait le point de l'expérience de l'utilisation de 2 robots mobiles, développés comme prototypes à la Ferme expérimentale de Trévarez et à l'Université de Liège

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See detailIs it possible for large herds to graze while keeping a high milk yield level? The experience of two Belgian dairy farms.
Lessire, Françoise ULiege; Hornick, Jean-Luc ULiege; Dufrasne, Isabelle ULiege

in van den Pol-van Dasselaer, Agnes; Aarts, H.F.M; De Vliegher, Alex (Eds.) et al Grassland and forages in high output dairy farming systems (2015, June 15)

Grazing is more and more abandoned because of increasing size of herds and automation of herd management (e.g. automatic milking system – AMS). In this context, this study aims to evaluate milk production ... [more ▼]

Grazing is more and more abandoned because of increasing size of herds and automation of herd management (e.g. automatic milking system – AMS). In this context, this study aims to evaluate milk production and composition of 2 large Belgian dairy herds equipped with AMS during winter and summer. These herds were followed over 2 years. At grazing, 30% of the offered feed was grass. Milk production in both herds was similar in summer and winter (30.2 ± 7.14 vs 29.7 ± 7.8 ± in Herd 1 and 26.9 ± 0.8 vs 26.4 ± 0.8 in Herd 2) while their milk composition differed. In conclusion, it is possible for grazing to be preserved even in large herds without impacting noticeably on the herd performance. [less ▲]

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