Portail des publications scientifiques de VetAgro Sup
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Cow factors to address when performing avoidance distance tests at the feeding rack
No full textInternational audienceThe human-animal relationship is an important component of farm-animal welfare. It is often assessed using 'avoidance distance', i.e. the distance at which animals avoid humans approaching them. However, this avoidance distance may be influenced by factors other than the human-animal relationship such as genetic background or health status. The objective of this cross-sectional epidemiological study was to assess the size of the effect of animal factors and testing conditions on the results of an avoidance test in dairy cows. Five observers applied a standardised test of avoidance distance at the feeding rack on 2 306 lactating cows from 103 dairy farms. We collected data on the independent variables: breed, parity and lameness, and height at withers, and calculated the height difference between the observer standing on the walking alley and each cow restrained at the feeding table. The avoidance distance of the cows, expressed in cm, was modelled using a linear mixed-effect model, with the above-mentioned independent variables as fixed factors, and the farm nested in observer as a random factor. The avoidance distance expressed in four categories as in the Welfare Quality protocol (2009) was modelled using a mixed effects ordinal regression with the same fixed and random factors. For the avoidance distance expressed in cm, we observed that intra-farm variability was twice as large as inter-farm variability (SD: 33.9 cm intra-farm vs 16.7 cm inter-farm). Avoidance distance increased by 7.0 cm (95%CI [3.8- 10.2]) when the cow was multiparous and increased by 4 cm (95%CI [0.2-0.6]) when the height difference between observer and cow increased by 10 cm. Avoidance distance decreased by 9.9 cm (95%CI [-19.6 - -0.3]) when the cow was lame and decreased by 6.4 cm (95%CI [-23.4 - -0.4]) when the cow breed was Montb & eacute;liarde vs Holstein. For the avoidance distance expressed in categories, there was a significant effect of the height difference and the parity. A greater height difference as well as multiparous cows had a slightly increased likelihood of reaching a higher avoidance distance category. We conclude that avoidance-test results are influenced by cow-related factors (parity, height difference to experimenter, lameness status, and breed). Thus, to reliably use the avoidance distance test to assess the human-animal relationship at farm level, we recommend careful sampling of cows for testing based on these factors. The measured avoidance distance can also be corrected with a coefficient based on animal-specific factors and height difference between observer and cows
A Collaborative Game to Assist Veterinary Undergraduate Students in the Conceptualization of a Research Dissertation
No full textInternational audienceThe veterinary thesis, mandatory in many veterinary curricula, represents an important step in terms of students' autonomy and research-led education. The choice of the topic is crucial, especially when the student initiates it rather than accepting a teacher's proposal. To promote diverse thesis work and provide greater support to students, a collaborative game and preparatory activity have been designed with a focus on the thesis project. The game was developed to raise awareness among students about the challenges of creativity and feasibility. The training sequence began with a short presentation by the instructor about the ideation process and project management tools. Then, under the instructor supervision, the students played using a deck of cards and worksheets. In the first phase, each group of students drew four cards and used them to imagine an experimental or a clinical thesis topic. The cards represented the elements of a PICO-like question (Population, Intervention, Comparison, Outcome). In the second phase, the groups exchanged their forms with another group, allowing them to evaluate each other's work and suggest modifications. This evaluation phase was based on “De Bono's 6 thinking hats method,” which encourages students to adopt different perspectives such as critical, creative, or objective thinking when assessing their peers' work. The student appreciation survey, conducted after the training, yielded positive results, particularly in terms of helping students identify different approaches to a topic and fostering collaborative peer discussions
Toxiques à tropisme cutanéo-muqueux chez le cheval
No full textInternational audienceSkin disorders in horses cas cause visible lesions and have a considerable impact on the animal's well-being. The cutaneous signs of intoxication are generallydue to primary or secondary photosensitisation reactions following the ingestion of toxic plants. Other toxins can also cause skin and mucous membrane disorders, such as vetch that causes dermatitis, spurge that have caustic effects, and pine processionary caterpillars due to the irritating hairs.Les affections cutanées rencontrées chez le cheval peuvent entraîner des lésions visibles et considérablement affecter son bien-être. Les signes cutanés d'une intoxication sont généralement dus à des réactions de photosensibilisation primaire ou secondaire à la suite de l'ingestion de plantes toxiqudes. D'autres toxiques peuvent également entraîner des troubles cutanéo-muqueux : la vesce à l'origine d'une dermatite, les euphorbes aux effets caustiques ou encore les chenilles procesionnaires avec leurs soies irritantes
Giardia duodenalis : importance médicale, morphologie et biologie
No full textInternational audienceLes infections par Giardia duodenalis, un protozoaire flagellé parasite de l'intestin, sont fréquentes chez le chien et d'autres mammifères, y compris l'humain, partout dans le monde. Cela a conduit l'Organisation mondiale de la santé (OMS) à le classer comme pathogène négligé nécessitant une surveillance accrue
Piroplasmose : voies de transmission de la mère au poulain
No full textInternational audienceLa piroplasmose équine est due à la multiplication de Theileria equi et/ou Babesia caballi dans les hématies (globules rouges) des équidés. Ces deux parasites sont habituellement transmis par les tiques, mais une transmission verticale de la jument infectée à son poulain semble également possible. Des cas d’avortements avec des avortons très infectés sont décrits de façon ponctuelle dans la littérature. Nous avons donc voulu évaluer la possibilité d’une transmission verticale à partir de juments porteuses asymptomatiques de piroplasmose vers leurs poulains. Sur une cohorte de 179 juments gestantes, nous avons démontré que cette transmission existait pour T. equi à un taux faible de 7,4 %. Sur les quatre poulains infectés, trois étaient en bonne santé et un quatrième est mort de cause non déterminée. Les voies de cette transmission restent incertaines, car l’analyse des placentas et ombilics n’est pas nécessairement en concordance avec le statut infecté ou non du poulain. Nous avons par contre mis en évidence la présence d’ADN de T. equi dans le colostrum d’une jument, ce qui soulève cette hypothèse comme voie possible de transmission
Le rôle des prairies dans la compensation des émissions de gaz à effet de serre des ruminants
No full textInternational audienceGrasslands play a role in the possible reduction of global warming by acting as carbon sinks, capable of offsetting some of the greenhouse gas emissions of cattle.Studies show that European temperate grasslands can capture more carbon than they emit, although this capacity stagnates after 30 to 40 years. To maximize the climatic benefits associated with grasslands, it is essential to preserve permanent grasslands, and thus avoid converting them to cropland, and to adopt practices such as agroforestry, organic matter input and rotational grazing. Although they cannot entirely compensate for the GHG emissions of cattle farming, grasslands are a lever in an overall strategy to mitigate the effects of greenhouse gases emissions.Les prairies jouent un rôle dans la possible réduction du réchauffement climatique en tant que puits de carbone, capables de compenser une partie des émissions de gaz à effet de serre des bovins. Les études montrent que les prairies tempérées européennes peuvent capter plus de carbone qu’elles n’en émettent, bien que cette capacité stagne après 30 à 40 ans. Pour maximiser les bénéfices climatiques associés aux prairies, il apparait essentiel de préserver les prairies permanentes, et donc d’éviter leur conversion en terres cultivées, d’adopter des pratiques telles que l’agroforesterie, l’apport de matière organique ou encore le pâturage tournant. Bien qu’elles ne puissent compenser entièrement les émissions de GES de l’élevage bovin, les prairies constituent un levier dans une stratégie globale d’atténuation des effets des gaz à effet de serre
Preferential localization of Escherichia coli in dairy emulsions: Influence of milk lipid droplets surface composition on bacterial adhesion
No full textInternational audienceIn food emulsions such as raw milk, the lipid droplets exhibit an interfacial layer possibly the site of interactions with bacteria, including the shiga toxin-producing Escherichia coli (STEC). Some pathogenic E. coli strains can adhere to intestinal cells after ingestion or to ligands that could modulate their pathogenicity such as those present at the surface of emulsion lipid droplets. The objectives of this study were to investigate the preferential localization of E. coli cells, AEEC 4315-A strain belonging to the O26:H11 serotype, as a function of the surface composition of emulsion lipid droplets i.e. milk fat globule membrane (MFGM) surrounding raw milk fat globules, milk polar lipids or whole milk proteins. The emulsions were artificially spiked with E. coli from an overnight culture in Brain Heart Infusion broth. Then, the E. coli cells were enumerated in the lipid droplet enriched creams and in the skimmed phases recovered after centrifugation. The localization of the E. coli cells in the creams was observed by confocal laser scanning microscopy (CLSM). This study revealed the role played by the surface properties of dairy lipid droplets on the adhesion of E. coli. For milk fat globules, the concentrations of E. coli in the creams were about 10 times higher than in the aqueous phase. In the processed emulsions, E. coli cells were concentrated in the aqueous phase. The CLSM images showed the adhesion of E. coli to the MFGM containing glycoproteins and their mobility as a function of time in the aqueous phase surrounding lipid droplets. This study provided additional scientific information supporting a specific affinity of E. coli for the MFGM of raw milk fat globules
Quel est le rôle de la faune sauvage dans l’épidémiologie de la leptospirose bovine ?
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Que sait-on du rôle des tiques dans la transmission de la fièvre Q aux ruminants ?
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Caenorhabditis elegans, un modèle utilisé pour le criblage de microbiotes fromagers à effet santé
No full textInternational audienceLes fromages sont des aliments fermentés et une source de micro-organismes lorsque nous les consommons. En effet, les fromages, et en particulier ceux au lait cru, sont connus pour leur grande biodiversité microbienne au sein de laquelle des micro-organismes bénéfiques pour la santé humaine sont présents. Après consommation, ils peuvent s'installer dans notre organisme et avoir un effet. Nous utilisons le modèle in vivo Caenorhabditis elegans pour rechercher les effets santé liés à la consommation de micro-organismes fromagers. C. elegans est un eucaryote invertébré rond à peau lisse et mesure environ 1 mm à l'âge adulte. Il vit dans le sol et principalement dans la végétation en décomposition où il se nourrit de micro-organismes (bactéries, levures). En laboratoire, il se nourrit exclusivement de la bactérie Escherichia coli OP50 et sa culture se fait en boîtes de Petri. Son anatomie très simple et facilement observable du fait de son corps transparent, en fait un modèle de choix pour l'étude de microorganismes ayant de potentiels effets sur la santé.</div