Caracterización de la ingestión por observación directa en rebaños ovinos del sureste de francia

When ruminants graze on heterogeneous vegetation, direct observation of bites is one of the most fitted method to estimate intake. Nevertheless its implementation in herds of more than 500 individuals has been scarce. In our study, this method was implemented to characterize the intake and know the feeding value offered by steppe vegetation. We observed two ovine flocks of 1100 and 1200 animals guided by shepherds in farm conditions. The animals used were Merinos d'Arles a breed with marked gregariousness. They constitute transhumant flocks that every spring graze the steppe vegetation of the Nature Reserve Coussouls de Crau located in Southeast France. The period of adaptation was brief lasting from 7 to 22 days. In this environment composed of a unique herbaceous layer, the intake rate was 5.9 ± 2.4 g DM/min, which is similar to levels reported in woody or shrubby rangelands. We found that in this steppe vegetation sheep are capable of flows up to 13 g DM/min. In previous studies the Brachypodium retusum has been considered of low nutritional value and little appreciated by the sheep. In our case it was found that the sheep eat a wide variety of plants. But when Brachypodium retusum contributes to the majority of dry matter intake, intake rate is significantly greater (6.8 g DM/ min) than when this is contributed by forbs (4.4 g DM/min) or by the other grasses (5.8 g DM/min). This plant is revalued, our results showed that it allows sheep to make bites of mass higher than forbs and other grasses which explains its improved efficiency of collection. Direct observation allowed us to characterize the intake of sheep in Crau steppe and we consider this type of vegetation as a food source similar to woody or shrubby rangelands.La observación directa de la ingestión es una herramienta pertinente bajo condiciones de cam- po y vegetación heterogénea, sin embargo ha sido poco utilizado en rebaños de más de 500 animales. En este estudio se implementó este método con el fin de caracterizar la ingestión y conocer el valor alimentario que ofrece una vegetación de estepa. Se observan dos rebaños de 1100 y 1200 ovejas conducidas por pastores en condiciones reales de explotación. Los animales utilizados fueron de raza Merino de Arles con marcado gregarismo, éstos constituyen rebaños transhumantes que pastorean durante cada primavera la vegetación estépica de la Reserva Natural de Crau situada en el Sureste de Francia. El período de acostumbra- miento fue corto, durando de 7 a 22 días. En este medio conformado únicamente del estrato herbá- ceo, la media del flujo de ingestión fue de 5,9 ± 2,4 g MS/min, lo cual es similar a los niveles reportados en sotobosque y matorrales. Se encontró que en esta vegetación estépica las ovejas son capaces de alcanzar flujos de hasta 13 g MS/min. En estudios anteriores el Brachypodium retusum ha sido considerado de bajo valor nutritivo y poco apreciado por las borregas. En este caso encon- tramos que las ovejas consumen una gran varie- dad de plantas. Pero cuando el Brachypodium retusum contribuye de manera mayoritaria a la materia seca ingerida, el flujo de ingestión es significativamente mayor (6,8 g MS/min) que cuan- do son mayoritarios los dicotiledones (4,4 g MS/ min) o las otras gramíneas (5,8 g MS/min). Se revaloriza así al Brachypodium retusum, los resul- tados mostraron que esta planta permite a las ovejas efectuar bocados de masa más elevada que las dicotiledóneas y las otras gramíneas, lo cual explica su mejor eficacia de colecta. La observación directa permitió caracterizar la in- gestión de ovinos en la estepa de Crau cuya vegetación puede ser considerada como recurso alimentario de valor similar al sotobosque y mato- rrales

Maintenance of daily intake through bite mass diversity adjustment in sheep grazing on heterogeneous and variable vegetation

International audienceConcerns about biodiversity preservation through grazing have revived interest in feeding choices made by herbivores. In this article, we study the dynamics of behavioural intake response in heterogeneous vegetation, where the size and quality of edible plants is highly diverse and varies from day to day as a result of grazing. We conducted two experiments with ewes grazing in paddocks located in shrubby rangelands. A direct in situ observation method was used, with continuous observation of ingestive bites taken by a continuously monitored individual. A bite coding-grid enabled us to distinguish the extreme diversity between bites masses and structure, including the ones resulting from plant depletion. Flock activities were also scan-sampled. Observations were made throughout complete paddocking sequences, which lasted for about two weeks. Grazing seriously depleted the paddocks since 75–95% of the herbaceous species was consumed. No trend was detected either in daily activity patterns or in intake time-budgets. These two variables were well synchronised between the continuously monitored individuals and their respective flocks. No inter-day trend was observed for dry matter daily intakes, which was twice higher than predictions from existing models on sheep intake. Our data enabled us to explore the relationship between the diversity of instantaneous feeding choices and the quantitative daily intake. On the instantaneous scale (20 s), we confirmed the functional relationship between bite mass and bite frequency. Little variation was observed in daily averages of ingestive behaviour components. But these averages hide the extremely large range of instantaneous values (from 0.04 to 1.2 g DM for bite mass). When vegetation size and structure declined as a result of grazing, the ewes progressively took larger bite masses with equivalent nutritive quality, thus adopting a pattern of consumption that is not consistent with the general assumption that such bites are chosen during the first day, as a result of the behavioural quantity–quality trade-off. This article provides knowledge about which type of diversity in plant parts size, structure and composition offers a small ruminant satisfying behavioural leeway in composing its meals and reaching physical satiety.We tend to discard pastoral management practices focused on biomass evaluation, and encourage further studies that will help qualify the nature and structure of vegetation that offers adjustment possibilities at both the individual and flock levels

Feeding behaviour of sheep on shrubs in response to contrasting herbaceous cover in rangelands dominated by Cytisus scoparius L.

International audienc

Conception et appropriation de MAE à obligation de résultat sur les surfaces herbagères : comment concilier pertinence écologique et agricole dans l'action publique en faveur de la biodiversité ? (acronyme DIVA2 : MAE Résultat)

Two agri-environmental measures (MAE) tied to an obligation of result aimed at pastureland management (Herbe_09) and preserving species-rich grassland (Herbe_07) were studied: genesis of these measures in Europe and in France, conditions of implementation in different areas and agroecological relevance. This type of MAE restores a sense of responsibility to farmers. Implementing these measures may generate a positive territorial dynamic in the sometimes contradictory debate over the best interests of farmers vs. ecological biodiversity conservation measures. Results show that their positive impact in terms of social, ecological and agricultural benefits supports the idea that they ought to be implemented on a wider scale, along with improved regulations, a better dialogue between farmers and environmental activists, and progress in technical and scientific knowledge.Les mesures agri-environnementales (MAE) visant la gestion pastorale (Herbe_09) et le maintien de prairies à forte richesse spécifique (Herbe_07) sont analysées : genèse de ces mesures en Europe et en France, conditions de leur mise en oeuvre dans plusieurs territoires et pertinence agri-écologique. Ce type de MAE est susceptible de redonner aux éleveurs une responsabilité valorisante ; leur mise en oeuvre peut entraîner une dynamique territoriale positive dans le débat parfois contradictoire entre agriculture et conservation de la biodiversité ; enfin, elles permettent de concilier production et biodiversité, mais sont peu propices à d’autres fonctions écologiques (pollinisation, séquestration du carbone...). Au final, leur bilan social, écologique et agricole, positif, incite à les généraliser mais en faisant progresser réglementation, concertation entre acteurs agricoles et environnementaux, et connaissances techniques et scientifiques

Analyse de la mise en œuvre des mesures agri-environnementales à obligation de résultat sur les surfaces herbagères

Les mesures agri-environnementales (MAE) visant la gestion pastorale (Herbe_09) et le maintien de prairies à forte richesse spécifique (Herbe_07) sont analysées : genèse de ces mesures en Europe et en France, conditions de leur mise en oeuvre dans plusieurs territoires et pertinence agri-écologique. Ce type de MAE est susceptible de redonner aux éleveurs une responsabilité valorisante ; leur mise en oeuvre peut entraîner une dynamique territoriale positive dans le débat parfois contradictoire entre agriculture et conservation de la biodiversité ; enfin, elles permettent de concilier production et biodiversité, mais sont peu propices à d'autres fonctions écologiques (pollinisation, séquestration du carbone...). Au final, leur bilan social, écologique et agricole, positif, incite à les généraliser mais en faisant progresser réglementation, concertation entre acteurs agricoles et environnementaux, et connaissances techniques et scientifiques

Analyse de la mise en œuvre des mesures agri-environnementales à obligation de résultat sur les surfaces herbagères

Les mesures agri-environnementales (MAE) visant la gestion pastorale (Herbe_09) et le maintien de prairies à forte richesse spécifique (Herbe_07) sont analysées : genèse de ces mesures en Europe et en France, conditions de leur mise en oeuvre dans plusieurs territoires et pertinence agri-écologique. Ce type de MAE est susceptible de redonner aux éleveurs une responsabilité valorisante ; leur mise en oeuvre peut entraîner une dynamique territoriale positive dans le débat parfois contradictoire entre agriculture et conservation de la biodiversité ; enfin, elles permettent de concilier production et biodiversité, mais sont peu propices à d'autres fonctions écologiques (pollinisation, séquestration du carbone...). Au final, leur bilan social, écologique et agricole, positif, incite à les généraliser mais en faisant progresser réglementation, concertation entre acteurs agricoles et environnementaux, et connaissances techniques et scientifiques