Contribution to the study of the technicoeconomic optimum of the calving interval of dairys cows in Walloon Region of Belgium, especially in the "Région herbagère liégeoise"

L’intervalle vêlage (IVV) s’allonge avec des impacts potentiels pour les éleveurs laitiers. Ainsi, l’objectif de ce travail de fin d’études est de contribuer à l’étude de l’optimum technico-économique de l’intervalle vêlage chez les vaches laitières en Wallonie, plus particulièrement en Région herbagère liégeoise. Un total de 1318 bilans comptables, collectés entre 2007 et 2012, auprès de 373 exploitations laitières, ont été travaillés à cette fin. Des analyses uni- et multivariées ainsi qu’une séparation de la variabilité typologique des fermes ont été réalisées pour mettre en évidence un lien entre l’IVV et les variables technico-économiques, et plus particulièrement la marge brute par vache traite (margeVT) et ainsi définir un optimum économique de l’IVV. Un IVV moyen du troupeau et un IVV représentatif (c’est-à-dire l’IVV le plus présenté par les animaux du troupeau) ont été attribués à chaque bilan comptable. De plus, des enquêtes ont été menées auprès de 5 éleveurs et 22 vétérinaires wallons pour confronter les résultats obtenus à la réalité du terrain. Sur base des résultats obtenus, il apparait que la relation entre l’IVV et la margeVT est faible (R = -8,5%) et que la margeVT n’est pas différente significativement entre les observations troupeaux*année des classes d’IVV représentatif court et long (P-valeur > 0,05). De plus, la margeVT des exploitations à IVV court ou long a tendance à se construire de la même manière si ce n’est que les exploitations à IVV long dépendraient plus fortement du prix du lait et les exploitations à IVV court des frais de cheptel par vache traite. A cause de ce faible impact de l’IVV sur les résultats économiques, un optimum technico-économique unique de l’IVV n’est pas déterminable au terme de ce travail. L’étude de la variabilité typologique des meilleures exploitations d’un point de vue économique montre que l’IVV moyen a tendance à augmenter avec l’intensification de l’alimentation et l’augmentation du niveau de production laitière des exploitations (coefficient de la courbe de tendance linéaire = 2,52, R2 = 66,83%). Il semble donc que l’optimum technico-économique de l’IVV varierait en fonction de la typologie de l’exploitation et aurait tendance à augmenter avec les deux paramètres cités précédemment. Cependant, selon les enquêtes, l’IVV du troupeau semble peu connu des éleveurs et plus subi que souhaité. Une conscientisation des éleveurs à l’IVV de leur troupeau, une acquisition de données individuelles ainsi que de données supplémentaires pour poursuivre l’étude de la variabilité typologique des exploitations sont des possibilités de recherche futures à explorer pour valider les résultats obtenus et pour offrir des pistes d’amélioration aux éleveurs.The calving interval (CI) is extending with potential impacts for the dairy breeders. In this way, the aim of this master thesis is to contribute to the study of the technicoeconomic optimum of the CI of dairy cows in Walloon Region of Belgium, especially in the “Région herbagère liégoise”. To this purpose a total of 1318 balance sheets, collected between 2007 and 2012 on 373 commercial dairy farms, were studied. Uni- and multivariate analyses were conducted, as well as a separation of the typological variability of the farms, in order to bring to light a link between the CI and the technicoeconomic variables and more particularly the gross margin per cow milked (GMCM) and thus to define an economic optimum of CI. A mean CI of the herd and a representative CI (which is the most common CI in the herd) have been assigned to each balance sheet. Moreover, surveys have been conducted with 5 dairy breeders and 22 Walloon vets in order to confront the results obtained with the situation in the field. On the basis of the obtained results, it can be observed that the relationship between the CI and the GMCM is weak (R = -0,085) and that the GMCM of the observations herd*year of the class representative short CI and the class representative long CI is not significantly different between these two classes (P-value > 0,05). The GMCM of the farms with short CI tend to be built up in the same way as with the long CI, except that the farms with long CI appears to depend even more on the milk price and the farms with short CI on the livestock costs. Because of the low impact of the CI on the economical results, a single technical and economical optimum of the CI has not emerged. The study of the typological variability of the best farms according to their economical results shows that the mean CI tends to rise with the intensification of the feeding and the increase of the level of the dairy production of the farms (coefficient of the linear trendline = 2,52, R2 = 66,83%). It therefore seems that the technicoeconomic optimum of CI tends to vary depending on the typology of the exploitation and to increase with the two herd parameters mentioned above. However, according to the surveys, the CI of the herd seems to be partly unknown by the breeders and more undergone than wished. Raising awareness of the breeders of the CI of their herd, gathering individual data as well as additional data in order to continue the study of the typological variability of farms are future options to explore in order to validate the results obtained and to provide ways of improvement to the breeders

Caracterisation of the diversity of the strategies conceived by Walloon dairy producers : socioeconomic determiners and dynamic of adaptations faced to the past, present and future issues

Agricultural producers are necessary for reasons of food security but they are subject to great economic, social and environmental issues, jeopardizing their continuity. More particularly, the European dairy producers have recently experienced a big change of their economic and political context following the end of the dairy quota system. For the sustainability of the sector and what this implies for our society and our environment, it is interesting to know the development paths implemented, planned and considered by the producers facing these changes. This thesis studied these development paths from the point of view of the producers, who are the first to be impacted by these changes of context and the first actors of solutions needed to adapt and maintain a profitable activity. The actions and the opinions of the Walloon producers were studied using the technicoeconomic database of Elevéo as well as surveys conducted in 2014-2015 and 2020. The objectives of the thesis were (1) to study the strategies of the producers and the evolution of these strategies in a recent past, their planning from 2020 onwards and their consideration for an ideal future, (2) to study the link between these strategies and other information, reflecting the causes of these choices, the environmental considerations, the wishes for training and the quality of life of the producers, providing an insight of the determining factors and the sustainability of these strategies, (3) to study the relevance to adapt the management depending on the adopted strategy(ies). First, the level of intensification was measured in this thesis thanks to an index created on the basis of several variables related to feeding, coming from the technicoeconomic database. This index aims to provide a more complete and exact measure tool of intensification. Its evolution between 2007 and 2017 was measured per individual to highlight the evolution patterns. We observed that 27% of producers were having a constant evolution, 8% a linear positive tendency, 24% a quadratic evolution with a maximum in 2012, which was a year of dairy crisis. Secondly, just before the end of the dairy quota system (2014-2015), 3 strategies of production in the short term in post quota era were studied and concerned: the increase of the milk quantity produced, the alternative valorization of milk production and the diversification of the activities. We found out that, according to the survey, more than half of the producers (55%) have chosen the status quo in quantity of milk produced, nearly 40% the increase of the production, 10% the alternative valorization and 10% the diversification of the activities. This shows that alternative activities were seldom considered by the producers on the eve of an important change of the production framework, in contrast to the increase of the dairy production activity. Thirdly, the characteristics of the ideal farm of the future were studied throughout 7 strategies : intensive vs. extensive, specialized vs. diversified, weakly vs. strongly based on new technologies, management by an independent producer vs. by an association of producers, familial vs. salarial workforce, production of milk with a standard vs. differentiated quality, for the global vs. local market. From the multivariate analysis of the answers of the producers collected in the 2014-2015 survey, clusters between some characteristics were observed, leading to highlight two models of ideal future farm : the “Local-based extensive”(LBE) model and the “Global-based intensive” (GBI) model supported, respectively, by 26% and 46% of producers respondents. The producers were positioning themselves more or less strongly regarding these two extremes. Hence, a gradient of ideal future farm (IFF) between the model LBE and GBI was defined to express the tendency of a producer to consider a model or the other as ideal. Significant relationships were then observed between the IFF gradient and the variables related to the reasons of the choice of this model, the environmental considerations and the training. Thus, the producers tending to GBI or LBE model do not have the same environmental considerations and represent two different guests in terms of training paths and areas. Fourth, the producers with different production systems were selected to answer a survey concerning their quality of life. No significant relationship was observed between the variables linked to quality of life and their production profile, except for the mixed producers (i.e., having several activities on the farm, i.e., 3rd group that standed out of the variability of the surveyed producers) who showed some lower quality of life results and for the extensive producers who were better supporting the society perception of the agriculture. Thus, the farm model does not seem to impact the quality of life of the producers, except if they have several activities. Fifth, we studied the relevance to vary a management parameter in particular, the calving interval (CI), as a function of the feeding systems. Significantly different gross margins per cow were observed between the herds having different percentages of cows with short or long CI, inside the different feeding systems. This chapter allowed to understand the effects of feeding on the herd and the importance to take them into account to define the herd management that maximizes the economic results. Finally, all these results allowed to establish a temporal evolution of the strategies of dairy producers, to provide an overview of the sustainability of the two models of farm supported for the future and to draw a scenario of the causes leading to this choice. The survey of 2020, conducted in Wallonia, allowed to bring additional information regarding the points raised in this thesis, 5 years after the end of the dairy quota system. The results of this survey validate or record the evolution of the tendencies observed previously and show a change of strategy concerning the ideal future farm. Indeed, the current occurrence is that 49% of the producers are in favour of LBE model vs. 33% of GBI model. In conclusion, the strategies of dairy producers are multiple and have evolved these last years, in relation to the available resources, the mentality of the producers and the changing framework, whose major event was the end of the dairy quota system. The occurrence of the producers between LBE and GBI is important to know given their economic, social and environmental sustainability. Thus, in order to build a suitable framework for the dairy activity for the next years and generations, this information must be taken into account by all the actors on the ground

Our cubicles on miscanthus

Une visite dans une ferme située dans la Manche démontre l'intérêt du miscanthus comme matériaux sur les logettes

First positive winter, for the "flour of straw" in cubicles

Une visite d'exploitation démontre l'intérêt de la farine de paille comme matériel sur les logettes

Water Vapor Permeability of Edible Films Based on Improved Cassava (Manihot esculenta Crantz) Native Starches

peer reviewedStarch is used in the production of edible biodegradable packaging as an attractive alternative to synthetic polymers because it is a natural biopolymer of low cost and high availability. Many studies have been carried out on films based on cassava starch and the results show that these have good flexibility and low water vapor permeability. This present research was conducted to analyse the effect of glycerol, peanut oil and soybean lecithin on the water vapor permeability (WVP) of edible films based on improved cassava (Manihot esculenta Crantz) native starches from Côte d’Ivoire. The films were prepared using 4 g cassava starch, 25% and 30% glycerol (w/w), 5% and 10% peanut oil (w/w) and 0% to 5% soybean lecithin (w/w oil) in Petri dishes. The WVP of the films was determined at 25°C and 75% relative humidity. The moisture content of the films was determined in an oven at 105°C and the film thickness was determined manually using a micrometer. The resulting films were homogeneous, transparent and crack-free. WVP, moisture content and thickness of the films increased with increasing glycerol concentration. Increasing the concentrations of the peanut oil and soybean lecithin decreased the thickness and increased the moisture content of the films. The combination of glycerol and peanut oil increased the WVP of the films, whereas addition of soybean lecithin had no effect. The lowest WVP values were obtained using 25% glycerol, 5% peanut oil and 5% soybean lecithin. Starch obtained from improved cassava varieties cultivated in Côte d’Ivoire can be a potential ingredient in the production of food packaging

Effect of wheel traffic on the physical properties of a Luvisol

The effects of machine traffic were assessed on a Luvisol in a temperate climate area in Belgium. Soil samples were taken from topsoil (0.07-0.25 m) and subsoil (0.35-0.50 m), on plots under long-term reduced tillage (RT) and conventional tillage (CT). Cone index (CI), bulk density (BD) and precompression stress (Pc) were chosen as indicators of mechanical strength. Mercury intrusion porosimetry was used to characterize the soil microporosity structure. It was presented in two forms: (i) cumulative pore volume vs. equivalent pore radius r, from which four classes of porosity were defined: r < 0.2 μm, 0.2 ≤ r < 9 µm, 9 ≤ r < 73 µm and r ≥ 73 μm; (ii) pore-size distribution (PSDs). In the reference situation where there had been no recent passage of machines, the voids with 0.2 ≤ r < 9 µm were the most important class in RT topsoil. The voids with r ≥ 73 µm represented the main porosity class in the topsoil of CT. In the subsoil, for both tillage systems, the porosity was almost equally distributed between voids with 0.2 ≤ r < 9 µm and voids with r greater than 9 µm. Machine traffic was carried out when the soil water content was close to the optimum Proctor. Although unfavourable, these wet conditions often occur during the beet harvesting period in Belgium. The highest modifications in soil structure (increase in BD and Pc, reduction of macroporosity r ≥ 73 μm) were observed in the topsoil of CT. More limited modifications were noticed in the soil structure of RT topsoil and subsoil layers but these latter are problematic in that the soil would no longer be loosened by subsequent tillage. These modifications could lead to soil consolidation as a result of wheel traffic year after year.Etude de la compaction des sol

Gamification croissante d’un quiz de chimie – Effets comparés sur la performance, la perception de compétence et l’état de flow

La littérature récente portant sur la gamification présente les mini-jeux comme une solution de rechange peu coûteuse aux « serious games » exigeant un investissement technique et narratif important. Cet article étudie en quoi l’utilisation de mini-jeux de chimie présentant une gamification croissante affecte la performance, le sentiment de compétence et l’état de flow d’étudiants en première année de bachelier bioingénieur. Les résultats n’enregistrent aucun effet sur les deux premiers paramètres, mais mettent en évidence un effet positif de la gamification sur quatre caractéristiques du flow. Ces résultats contrastés servent d’amorce à une discussion sur les conditions d’efficacité des mini-jeux dans l’enseignement supérieur.Mini-games have recently emerged in the literature on gamification as an affordable alternative to immersive serious games. The present study aims to evaluate the effects of the use of chemistry mini-games having a growing gamification on the performance, the self-confidence and the flow perceived by first year bioengineering students. Results indicate no effect on the first two parameters but show a positive effect on four dimensions of the flow. Given these mixed results, the conditions of an effective use of mini-games with undergraduate students are then discussed

Impact de l'intervalle vêlage sur les résultats économiques des fermes laitières, basé sur leur typologie

The calving interval (CI) can influence the milk production (MP) and the economic results of a farm. This research aimed to highlight the most economically important CI, on the basis of the accounts of breeders. The data set contained 1,318 accounts spread between 2007 and 2012. Technical information such as mean CI of the herd, percent of cows with a CI of less than 380 d (m380), between 380 and 419 d (e380419), between 420 and 459 d (e420459) and more than 459 d (p459), mean MP of the herd; as well as typological information such as quantity of equivalent concentrate (CC), number of ares of grass (GR) and of corn silage (CS) per livestock unit (LU); and economic information such as mean gross margin per cow were available. The relation between CI and the gross margin showed that if a single economic optimum of CI cannot be determined, this optimum could depend on the typology of the farm. Therefore, 4 groups were created by using a multiple correspondence analysis, including quantity of equivalent CC, number of ares of GR and of CS per LU as variables. The first group was the most intensive one with a feeding based mostly on CC and CS; the second group was similar but less intensive. The third group was the most extensive with high GR consumption. The fourth group was characterized by a near absence of CS but more CC. Moreover, m380, e380420, e420459, p459 were transformed from quantitative to qualitative variables by using numerical classification. A qualitative variable CI profile was created as a summary of all these variables. In each group, MP was modeled using the different CI variables. The assumption behind this modeling was that for a typological profile, the breeder must have the highest MP to maximize the gross margin. These models showed that MP is maximized when p459 is lower than 26%, lower than 37%, above 27% for the group 1, 2, 3 respectively. For the group 4, the model with the variable CI profile suggested that the economic optimum of CI is intermediate. These results underlined that the economic optimum of CI is related to the typology of the considered farm. Studying individual data is a perspective to determine more precisely CI with the best economic results