Milk fatty acids and cheese from hay based diet and continuous or rotational grazing

International audienceThis work compares Cantal cheeses obtained from three groups of 12 Montbéliarde cows fed either a hay-based diet (H) or grazing two mountain pastures: a diversified pasture (74 species) grazed continuously (E) and a less diversified (31 species) old temporary grassland, grazed rotationally (R). Under controlled conditions 27 cheeses were manufactured during three consecutive days in early June, July and late August in 2008. Cheese H was, on average, firmer, less melting and less yellow than cheeses E and R, which did not differ. Total saturated FA (SFA) and monounsaturated FA (MUFA) percentages were respectively higher and lower in H milks than in pasture milks. Vaccenic and oleic acids and polyunsaturated FA (PUFA), cheese colour and melting texture decreased during the season in E, while they remained constant in R because of a combined effect of the grass vegetative stage and selective grazing. Our results underline the relationship between milk FA profile and cheese texture. Keywords

Conformational stability and in vitro bioactivity of porcine luteinizing hormone

International audienc

Biodiversity and factors of variation of microbial flora on the teats of dairy cows

International audienceTo determine how farming practices and the intrinsic characteristics of individual dairy cows can influence the composition of the microbial community on teat skin, sixteen dairy farms in the Cantal region of France were studied. Microbial groups of the teat skin of 6 dairy cows per farm were counted using 10 dairy-specific media. Farms were classed into three groups according to the milking hygiene practices, the litter and the forage. Cows were also classed into three groups according to individual characteristics. Teat hygiene seems to be the factor that causes the greatest changes in the level of microbial flora on the teat. Whatever the type of practice, rather young cows are associated with lower levels of microbial flora on the teat skin. The microbial community on cow teat skin belonging to 3 groups of farms was evaluated by combining a culture-dependent method and a direct molecular approach. The diversity of this microbial community was large as 79.8% of clones corresponded to unidentified and 66 identified species belonging to most of those commonly found in raw milk. Then teat skin is an interesting source or vector of biodiversity for milk

La surface de trayon des vaches laitières : un réservoir de biodiversité ?

National audienc

Etude socio-économique de systèmes laitiers de moyenne montagne sous AOP fromagère (St Flour, Cantal) : trajectoires et stratégies pour améliorer la robustesse des systèmes de production

International audienceIn response to the decreasing number of dairy farms and associated workers, municipalities of the Saint-Flour area (Cantal, France) commissioned a study which aimed to better understand and describe the structures and common strategies to putatively robust dairy farms. Fifteen farms were selected and surveyed for their putative robustness. Four main successful strategies associated with improved robustness towards economic, social and environmental risks were highlighted: i) to prioritize forage autonomy through a maximization of grass use and parsimonious concentrate feeding and purchase, ii) to enhance milk paid in link with its intrinsic quality (increases of milk solids contents…) and/or through the milk delivery to dairy plants oriented to high value-added markets, iii) to diversify the income sources with enhancement of the meat byproduct from the dairy herd and/or with the introduction of a suckling cow/ewe herd, or a farmhouse cheese plant, and iv) to reduce structural expenses by subcontracting tasks or by cooperative use of agricultural equipment and/or by very limited investments in equipment and building. Based on this assessment, a panel of proposals will be proposed to stakeholders and decision makers in order to promote those successful strategies via extension programs

Évaluation de la performance environnementale (ACV) des exploitations laitières en polyculture-élevage : base pour un changement de pratiques au sein des systèmes de production ?

National audienc

Management of microbial diversity at milk production for raw milk cheeses

International audienc

Accompagner les producteurs laitiers pour orienter les équilibres microbiens des laits en faveur de la qualité des fromages au lait cru

Les filières fromagères AOP ont conscience de la nécessité de changer de stratégie au niveau des élevages pour préserver les microorganismes favorables à la transformation fromagère, et ainsi maintenir la richesse des fromages au lait cru. Pour répondre à leurs interrogations, un programme de Recherche et Développement sur l’accompagnement des producteurs de laits a été mis en place, afin de fournir des outils aux techniciens accompagnant les producteurs. Dans ce cadre, une démarche d’accompagnement a été testée dans dix entreprises de collecte et de transformation fromagère au lait cru représentant six filières fromagères AOP. Sur la base d’une analyse sociologique et technique des démarches tests, des échanges de savoir-faire entre les acteurs impliqués, des outils innovants ont été conçus (démarche d’accompagnement au changement, méthodes d’analyses de la composition microbiologique des laits, diagnostic des pratiques d’élevage, module de formation) pour sensibiliser les acteurs des filières et faire évoluer à la fois les comportements et les pratiques en élevage. De nouvelles connaissances ont été acquises sur les réservoirs de microorganismes susceptibles d’ensemencer le lait et sur l’influence des pratiques d’élevage notamment sur l’hygiène post-traite au travers d’une expérimentation en milieu contrôlé.PDO cheeses network has become aware that a change of strategy in animal husbandry is needed to preserve the microbial flora of interest in cheese-making and so to maintain the specificity of raw milk cheeses. To answer to their question, a program of research and development was set up, to supply the useful tools to the technicians who advice milk producers. In this context, an advisory method was tested in ten small dairies using raw milk representing six French PDO cheeses. On the basis of a sociological and technical analysis of the advisory methods tested, the involved actors exchanged about their own “know-how”, innovative tools have been designed (advisory method to a change of attitudes, analytical methods of the milk microbiota, diagnostic tool of breeding practices, applied training course) to make PDO cheeses actors aware and induce change in behaviour and breeding practices. New knowledge has been obtained on microorganisms potential reservoirs that can be sources of milk inoculation and on the influence of farming practices in particular through an experiment on post-milking hygiene in a controlled environment