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9èmes Journées techniques Ovines; National audience

International audience; In this paper, our objective was to study the consistency of the mineral composition of leaves from Fraxinus excelsior L. according to their provenance and management, i.e. pollarded vs. high stem trees. The leaves were collected in August 2016 on 7 sites spread out in 3 regions of France. The concentrations in Ca, Na, Fe, Mn and Cu of ash tree leaves, exhibited a high variability (coefficient of variation, C.V.>30%), while the concentrations in N, K, Mg, P, and Zn varied in a lesser extent (C.V.

Over the past decade, the INRA centre in Lusignan has been testing a range of forage solutions. The goal is to improve feed security in dairy systems, which are facing climatic variability and, more specifically, summer droughts. Two main strategies have been explored for producing forage throughout the year in a water- and energy-efficient manner: allowing animals to graze and feeding animals conserved forage. Hem, we discuss methods for extending the grazing season and forage resources by filling the gaps between the mixed temporary grasslands; for example, grains, millet, or stockpiled grassland could be used. We also assess the ability of sorghum and grain-protein crop associations to ensure forage availability. Finally, we examine the results obtained using an experimental low-input forage system, OasYs, that has been in place since 2013. OasYs was specifically designed to deal with climate change and combines several of the solutions discussed., Deux grandes voies complémentaires ont été explorées pour produire des fourrages tout au long de l’année, en économisant l’eau et l’énergie fossile : le pâturage et les fourrages conservés. Nous présentons les résultats obtenus sur des ressources fourragères destinées à allonger la saison de pâturage et à prendre le relai de prairies temporaires diversifiées (céréales, millet, stocks sur pied de couverts prairiaux). L’intérêt du sorgho et des associations céréales-protéagineux pour sécuriser les stocks est également discuté, à partir des différentes modalités que nous avons mises en place. Enfin nous présentons les premiers résultats d’un système fourrager à bas niveau d’intrants, conçu pour être adapté au changement climatique et combinant plusieurs de ces solutions.

The nutritive value of a set of 10 woody forage resources (Italian alder, ash, chestnut, field elm, hazel, lime, black locust, white mulberry, holm oak and vine) was investigated. Leaves were collected in summer 2015. Protein and fibre concentrations, condensed tannin concentration, in vitro digestibility (enzymatic method), and dry matter (DM) and nitrogen in sacco effective ruminal degradability were determined. Results show a large variability between species: crude protein varied from 82 to 245 g kg‑1 DM, in vitro digestibility from 47 to 84%, and effective nitrogen degradability from 18 to 78%. White mulberry is the most interesting species but ash, alder, elm and lime also present sufficient in vitro digestibility and nitrogen characteristics to be included in the diet of ruminants. Black locust, vine and holm oak present high levels of condensed tannins and low effective nitrogen degradability.

To face the new challenges of dairy farming in North-Western Europe, an innovative dairy system was redesigned to produce milk in a context of climate change while saving scarce resources (water, fossil energy) and contributing to a sustainable agriculture. This system, called OasYs, is based on the diversification of forage resources, the development of grazing, larger use of legumes and on a consistent strategy for the livestock system (Novak et al., 2015). The main research hypothesis is that the increase of diversity allows to conciliate production levels and environmental performance, this way improving system resilience.

Objetivou-se avaliar a composição químico-bromatológica e a digestibilidade aparente de dez híbridos de milho (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistache e Buxxil) cultivados no INRA (Unité de Génétique et d’Amélioration des Plantes Fourragères, Lusignan-France), em parcelas de 150 m2, com trêsrepetições. Para o estudo de digestibilidade in vivo, os ovinos foram alimentados com silagem da planta inteira dos híbridos de milho com três repetições. Os híbridos de milho foram avaliados antes de ensilados pelo método NIRS, em que se pode constatar que houve diferença (p < 0,05) entre os híbridos para a composição química. Quanto aos valores de digestibilidade in vivo, observou-se que, o DK265bm3 se destacou dos demais híbridos quanto aos valores de MS, MO, celulose, PC e da DIVMS.The objective of this experiment was to evaluate the chemical-bromatological composition and apparent digestibility of ten hybrids of corn (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistachio and Buxxil) planted at INRA (Unité of Génétique Amélioration des Plantes Fourragères, Lusignan-France), in 150 m2 areas with three replications. The digestibility study was conducted using sheep fed corn hybrid whole plant silage with three replications. Corn hybrids were evaluated before ensilage using NIRS, and a significant difference (p < 0.05) was observed among treatments for chemical composition. DK265bm3 showed higher values than other hybrids for digestibility of DM, OM, cellulose, NDF and for IVDMD.

It was aimed to evaluate the ruminal degradability, and the fractioning of carbohydrates, as well as of the nitrogen fractions of triticale silages in singular culture or in mixtures with oats and/or legumes. The treatments had been: triticale silage (X. Triticosecale Wittimack) (ST); triticale silage + forage pea (Pisum arvense) (STE); triticale silage + oats (Avena strigosa Scheb) + forage pea + vetch (Vicia sativa) (STAE). Three castrated bovine Prim’Holstein males had been used, with average live weight of 300 kg, having ruminal cannulas. The incubation times had duration of 0, 6, 12, 24, 48, 72 and 96 hours. Fractions, a, c and ED of the DM of STAE silage was higher (30,33; 0,026 and 45,45%) than others silages. Fraction b of the DM of ST silage was higher (58,45%) than STE silages (45,36%) and STAE (44,37%). In CP the ST silage presented higher fraction (72.12%). For the potentially degradability fraction (b) of CP it was not observed difference among treatments. The degradation rate (c) of the CP was higher for STE silage (0.063%) than ST ensilage (0,012%), however this was similar to the STAE (0,045%). ED of CP was better for STE silage (77,71%). ST silage presented fraction a and b for NDF highest (8,62 and 81,99%) than others silages. The degradation rate (c) of NDF was higher for STAE (0,027%). ED for NDF did not present difference among treatments. ST silage presented the best values for the total carbohydrates (83,97%) than STE (79,87%) and STAE silages (76,77%). STE and STAE silages presented better DM degradability and suggest to be a potential source of non degradable protein in the rumen. The exclusive triticale silage revealed superior with regard to the degradability of fiber fraction, also presenting higher amount of total carbohydrates potentially degraded.O objetivo desse trabalho foi avaliar a degradabilidade ruminal, e o fracionamento de carboidratos, assim como das frações nitrogenadas das silagens de triticale em plantio singular ou em misturas com aveia e/ou leguminosas. Os tratamentos foram: silagem triticale (X. Triticosecale Wittimack) (ST); silagem de triticale + ervilha forrageira (Pisum arvense) (STE); silagem de triticale + aveia (Avena strigosa Scheb) + ervilha forrageira + ervilhaca (Vicia sativa) (STAE). Foram utilizados três machos bovinos castrados da raça Holandesa, com peso vivo médio de 300 kg, portadores de cânula ruminal. Os tempos de incubação empregados tiveram a duração de 0, 6, 12, 24, 48, 72 e 96 h. As frações a, c e a DE da MS da silagem STAE foram maiores (30,33; 0,026 e 45,45%) em relação às demais silagens. A fração b da MS da silagem ST foi maior (58,45%) em relação às silagens STE (45,36%) e STAE (44,37%). Na PB a silagem ST apresentou maior fração a (72,12%). Na fração potencialmente degradável (b) da PB não houve diferença entre tratamentos. A taxa de degradação (c) da PB foi maior para a silagem STE (0,063%) em relação à silagem ST (0,012%), porém esta foi semelhante à STAE (0,045%). A DE da PB foi melhor na silagem STE (77,71%). A silagem ST apresentou fração a e b da FDN maior (8,62 e 81,99%) em relação às outras silagens. A taxa de degradação (c) da FDN foi maior para STAE (0,027%). A DE da FDN não apresentou diferença entre tratamentos. A silagem ST apresentou os melhores valores dos carboidratos totais (83,97%) em relação às silagens STE (79,87%) e STAE (76,77%). As silagens STE e STAE apresentaram melhor degradabilidade da matéria seca e sugerem ser potencial fonte de proteína não-degradável no rúmen. A silagem exclusiva de triticale mostrou-se superior com relação à degradabilidade da fração fibrosa, apresentando também maior quantidade de carboidratos totais potencialmente degradáveis.

The purpose of the present study was to compare dry matter yield and nutritive value of conventional hybrid grain sorghum [(Sorghum bicolor (L.)] as influenced by row spacing, with conventional hybrid maize (Zen mays L.). Sorghum hybrid var. Solarius was planted at two distances between rows, 75 and 20 cm, and maize var. Anjou 387 at 75 cm (conventional planting). Dry matter yield (DMY) in both species decreased over the years, being this fall greater in maize. DMY fell by 20.7, 6.5 and 5 t ha(-1) in 2009 when compared to 2007 for maize, sorghum 75 and 20 cm, respectively, indicating that DMY in sorghum 20-cm was less affected by a drop in rainfall than in the other treatments. When averaged over the years, sorghum 20-cm showed the higher protein concentration, 104.1 g kg(-1) MS vs 89.4 and 70.5 g kg(-1) DM for sorghum 75-cm and maize, respectively. Digestibility in maize was higher than in the average of the two sorghum treatments, 692 vs 636 g kg(-1) DM, respectively. Lignin concentration in maize was 18 vs 28.8 g kg(-1) DM for the average of the two sorghum treatments. However, digestibility in both sorghum treatments increased by 77.2 g kg(-1) MS from 2007 to 2009. Maize was more sensitive to environmental variations. Sorghum planted at 20 cm between rows shows both greater DMY and protein concentration than maize in dry matter yield when rainfall is a limiting factor.; El objetivo fue comparar el rendimiento de materia seca y el valor nutritivo de un híbrido convencional de sorgo [(Sorghum bicolor (L.)], establecido a dos distancias entre surcos, con un híbrido convencional de maíz (Zea mays L.). El sorgo var. Solarius fue establecido a 75 y 20 cm entre surcos, y el maíz var. Anjou 387 a 75 cm (siembra convencional) en 2007, 2008 y 2009 en Lusignan, Francia. El rendimiento de materia seca (RMS) en ambas especies declinó con los años y esta disminución fue mayor en maíz. El RMS para 2009 fue menor en 20.7, 6.5 y 5 t ha-1, al compararlo con 2007, con respecto a maíz, sorgo 75 y 20 cm, lo que indica que la reducción de lluvia afectó menos el RMS del sorgo 20-cm. Al promediar los años, sorgo 20-cm tuvo mayor proteína con 104.1 g kg-1 MS vs 89.4 y 70.5 g kg-1 MS de sorgo 75-cm y maíz, respectivamente. El maíz tuvo más alta digestibilidad que el promedio de los dos tratamientos de sorgo con 692 vs 636 g kg-1 MS. La digestibilidad fue mayor en maíz debido a su menor concentración de lignina. La concentración en lignina del maíz fue 18 vs 28.8 g kg-1 MS del promedio de los dos tratamientos de sorgo. Sin embargo, la digestibilidad de ambos tratamientos de sorgo aumentó en 77.2 g kg-1 MS al pasar de 2007 a 2009. El maíz fue más sensible a los cambios ambientales. El sorgo sembrado a 20 cm entre surcos fue superior en RMS y en concentración de proteína que el maíz, cuando las condiciones de lluvia son un factor limitante.

The objective of the present study was to evaluate the aerobic stability and losses during the fermentation process of triticale silages in single crop or in mixtures with oats and/or legumes. The following crops were used for silage production: triticale (X. Triticosecale Wittimack), triticale intercropped with forage pea (Pisum arvense) and triticale intercropped with oats (Avena strigosa Schreb), forage pea and vetch (Vicia sativa). The dry matter content and its recovery did not differ among the silages. Buffer capacity was higher for tricale silage intercropped with oats, forage pea and vetch(88.67 m eq. NaOH/100 g DM) followed by triticale intercropped with forage pea (80.80 m eq. NaOH/100 g DM). Electric conductivity values were higher in the intercropped triticale silages. Triticale silage presented the lowest temperatures observed in the silos, and the silages of intercropped triticale silages presented higher heat retention and higher pH values. Silage of triticale intercropped with oats and legumes presented lower aerobic stability but it did not reduce the aerobic stability of the total feed. Dry matter recovery during storage and in stability evaluations in aerobiosis is similar among the silages.O objetivo neste trabalho foi avaliar a estabilidade aeróbia e as perdas durante o processo de fermentação de silagens de triticale em cultivo exclusivo ou em misturas com aveia e/ou leguminosas. As culturas utilizadas para produção das silagens foram: triticale (X. Triticosecale Wittimack); triticale em consórcio com ervilha-forrageira (Pisum arvense); e triticale em consórcio com aveia (Avena strigosa Schreb), ervilha-forrageira e ervilhaca (Vicia sativa). O teor de matéria seca e a recuperação de matéria seca não diferiram entre as silagens. A capacidade tampão foi maior para a silagem de triticale cultivado em consórcio com aveia, ervilha-forrageira e ervilhaca (88,67 m eq. NaOH/100 g de MS), seguida da silagem de triticale cultivado em consórcio com ervilha-forrageira (80,80 m eq. NaOH/100 g de MS). Os valores de condutividade elétrica foram maiores nas silagens de triticale cultivado em consórcio. A silagem de triticale apresentou as menores temperaturas observadas nos silos, e as silagens de triticale cultivado em consórcio, maior retenção de calor e maiores valores de pH. A silagem de triticale em consórcio com aveia e leguminosas apresenta menor estabilidade aeróbia e não reduz a estabilidade aeróbia da ração total. A recuperação de matéria seca durante a armazenagem e na avaliação da estabilidade em aerobiose é semelhante entre as silagens.

Objetivou-se avaliar os efeitos das silagens de sorgo granífero, sorgo sacarino e milho sobre a ingestão, produção e composição química do leite e a digestibilidade dos nutrientes em vacas em lactação. Foram utilizadas 24 vacas da raça Prim'Holstein (PO), divididas em três lotes de oito vacas para avaliação das seguintes silagens: silagem de milho (SM); silagem de sorgo granífero (SG); e silagem de sorgo sacarino (SS). As silagens foram fornecidas à vontade com dois concentrados comerciais, distribuídos de acordo com o nível de produção leiteira. A silagem de sorgo granífero promoveu maior ingestão de MS (22,98 kg/dia) em comparação às silagens de milho (21,95 kg/dia) e de sorgo sacarino (19,43 kg/dia). A ingestão de água (litros/vaca/dia) foi semelhante entre os animais alimentados com silagem de milho (71,91) e de sorgo granífero (76,30) e menor nos animais alimentados com silagem de sorgo sacarino (56,95). A produção de leite total (28,81; 24,69 e 24,14 kg/dia) corrigida a 4% de gordura (30,65; 25,63 e 26,10 kg/dia) foi maior entre as vacas alimentadas com silagem de milho, no entanto, a porcentagem de gordura do leite das vacas alimentadas com silagem de sorgo sacarino foi maior (4,56%) em comparação àquelas alimentadas com silagem de milho (4,39%) e silagem de sorgo granífero (4,31%). A porcentagem de proteína foi maior (3,25%) no leite das vacas alimentadas com silagem de milho, intermediária no leite das vacas alimentadas com silagem de sorgo sacarino (3,05%) e menor no leite das vacas alimentadas com silagem de sorgo granífero (2,97%). Os coeficientes de digestibilidade dos nutrientes foram maiores nas vacas alimentadas com a ração à base de silagem de sorgo sacarino em comparação às rações à base de silagem de sorgo granífero e de milho.The effect of feeding grain sorghum silage, sweet sorghum silage, and corn silage on intake, milk production, milk composition, and nutrient digestibility of lactation dairy cows was evaluated. Twenty-four Prim'Holstein (PO) cows were used, forming three groups of eight cows each. The experimental treatments were: 1) corn silage; 2) grain sorghum silage; and 3) sweet sorghum silage, fed ad libitum, with two commercial concentrates, distributed following the cow milk production. Grain sorghum silage promoted greater DM intake (22.98 kg/day) compared to corn silage (21.95 kg/day), and sweet sorghum silage (19.43 kg/day). Dry matter intake was greater for corn silage than for sweet sorghum silage. Water intake (L/cow/day) was similar for the animals fed corn silage (71.91) and grain sorghum silage (76.30), and both were greater than the water intake of animals fed sweet sorghum silage (56.95). Total milk production (28.81; 24.69 and 24.14 kg/day), 4% fat corrected milk (30.65; 25.63 and 26.10 kg/day), and milk chemical composition was greater for cows fed corn silage when compared to the ones receiving grain sorghum silage and sweet sorghum silage. Cows fed sweet sorghum silage, but showed higher milk fat percentage (4.56%) compared to cows fed corn silage (4.39%) or grain sorghum silage (4.31%). Milk protein concentration was higher for cows fed corn silage (3.25%), intermediate for cows fed sweet sorghum silage (3.05%), and lower for the ones fed grain sorghum silage (2.97%). Nutrient digestibility coefficients were greater for cows fed sweet sorghum silage compared to other silages.

O objetivo foi avaliar a caracterização morfoanatômica e suas possíveis correlações com a digestibilidade da parede celular e com a lignina de dez híbridos de milho (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistache e Buxxil), plantados no INRA (Unité de Génétique et d’Amélioration dês Plantes Fourragères, Lusignan-França), em parcelas de 150 m². O delineamento utilizado foi inteiramente casualizado com cinco repetições por tratamento. Com exceção ao comprimento do córtex, verificou-se que os híbridos apresentaram diferenças significativas (p < 0,05) quanto aos aspectos anatômicos avaliados, sendo que o híbrido DK265bm3 se caracterizou por apresentar menor quantidade de células lignificadas, tanto na região medular quanto na região do córtex, menor porcentagem de parênquima medular e maior porcentagem do córtex em relação aos demais híbridos. Porém, o híbrido DK265bm3 não diferiu dos demais quanto à superfície do feixe vascular e espessura da parede celular do feixe vascular. Por meio de análises de correlação, verificou-se correlação positiva entre os teores de lignina klason e lignina em detergente ácido com as quantidades de células lignificadas no parênquima e córtex. A DIVFDN apresentou correlação negativa com a proporção de células lignificadas no parênquima medular e células lignificadas no córtex.The objective was to evaluate morphoanatomical characteristics and possible correlations with cell wall digestibility and with lignin of ten corn hybrids (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistachio and Buxxil) planted at INRA (Unité of Génétique Amélioration des Plant Fourragères, Lusignan, France) in 150 m² areas. A completely randomized experimental design with five replications was used. With exception for cortical length, significant differences were verified as for the evaluated morphoanatomical aspects, with hybrid DK265bm3 being characterized by lower counts of lignified cells in the medullar parenchyma and cortical areas, lower percentage of medullar parenchyma and higher percentage of cortex in relation to other hybrids. However, DK265bm3 did not differ from other hybrids in regards to vascular bundle surface and cell wall thickness of the vascular bundle. Using correlation analysis a positive correlation was observed between the levels of Klason lignin and lignin in acid detergent with the number of lignified cells in the parenchyma and cortex. IVCNDF showed a negative correlation with the proportion of lignified cells in medullar parenchyma and lignified cells in the cortex.

O objetivo foi avaliar a caracterização morfoanatômica e suas possíveis correlações com a digestibilidade da parede celular e com a lignina de dez híbridos de milho (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistache e Buxxil), plantados no INRA (Unité de Génétique et d’Amélioration dês Plantes Fourragères, Lusignan-França), em parcelas de 150 m². O delineamento utilizado foi inteiramente casualizado com cinco repetições por tratamento. Comexceção ao comprimento do córtex, verificou-se que os híbridos apresentaram diferenças significativas (p < 0,05) quanto aos aspectos anatômicos avaliados, sendo que o híbrido DK265bm3 se caracterizou por apresentar menor quantidade de células lignificadas, tanto na região medular quanto na região do córtex, menor porcentagem de parênquima medular e maior porcentagem do córtex em relação aos demais híbridos. Porém, o híbrido DK265bm3 não diferiu dos demais quanto à superfície do feixe vascular e espessura da parede celular do feixe vascular. Por meio de análises de correlação, verificou-se correlação positiva entre os teores de lignina klason e lignina em detergente ácido com as quantidades de células lignificadas no parênquima e córtex. A DIVFDN apresentou correlação negativa com a proporção de células lignificadas no parênquima medular e célulaslignificadas no córtex.The objective was to evaluate morphoanatomical characteristics andpossible correlations with cell wall digestibility and with lignin of ten corn hybrids (DK265bm3, DK265, HS5, HS6, HTV2, HTV27, Anjou285, Mexxal, Pistachio and Buxxil) planted at INRA (Unité of Génétique Amélioration des Plant Fourragères, Lusignan, France) in 150 m² areas. A completely randomized experimental design with five replications was used. With exception for cortical length, significant differences were verified as for the evaluated morphoanatomical aspects, with hybrid DK265bm3 being characterized by lower counts of lignified cells in the medullar parenchyma and cortical areas, lower percentage of medullar parenchyma and higherpercentage of cortex in relation to other hybrids. However, DK265bm3 did not differ from other hybrids in regards to vascular bundle surface and cell wall thickness of the vascular bundle. Usingcorrelation analysis a positive correlation was observed between the levels of Klason lignin and lignin in acid detergent with the number of lignified cells in the parenchyma and cortex. IVCNDF showed a negative correlation with the proportion of lignified cells in medullar parenchyma and lignified cells in the cortex.

L’élevage laitier doit faire face à de nouveaux défis : produire du lait dans un contexte de changement climatique, en économisant les ressources en voie de raréfaction (eau et énergie fossile), tout en contribuant à une agriculture durable. Dans ce cadre, un système laitier innovant basé sur une diversification des ressources fourragères, l’allongement du pâturage, le développement des légumineuses et une stratégie d’élevage adaptée, est mis en place à Lusignan (Poitou-Charentes). Nous faisons l’hypothèse que la résilience du système face aux aléas climatiques passe par une plus grande diversité de ses composantes et de leurs fonctions, cette diversité permettant également de concilier un niveau de production et des performances environnementales élevées. Les prairies temporaires sont au coeur de ce système bioclimatique baptisé OasYs. Elles sont diversifiées à la fois au niveau des espèces et des variétés et de leurs assemblages, mais également au niveau de leurs strates et de leurs modes d’exploitation., Dairy farming has to face new challenges, i.e. to produce milk in a context of climate change while saving scarce resources (water, fossil energy) and contributing to a sustainable agriculture. In this frame, an innovative dairy system, based on the diversification of forage resources, the development of grazing, a larger use of legumes and on a consistent strategy for the livestock system, is implemented in Lusignan (Poitou-Charentes). The main research hypothesis tested is that the resilience of the system to climatic hazards goes through a greater diversity of its components and of their functions, which allows also to conciliate good production levels and high environmental performance. Temporary grasslands are in the heart of this bioclimatic system called OasYs. They are diversified regarding their species, cultivars and their mixtures, but also regarding their three-dimensional space and their management.

International audience

A composição químico-bromatológica e a digestibilidade in vitro de cinco genótipos de milho (F2, Lu16, F271, Lu5 e Lu6) foram avaliados em Druelle-France, em parcelas de 150 m2 com duas repetições. O delineamento experimental utilizado foi em blocos ao acaso. Todas as avaliações do estudo foram realizadas em plantas inteiras sem espigas. O genótipo Lu16 foi o que apresentou os maiores valores para a digestibilidade da matéria seca (69,82%) e digestibilidade da parede celular (48,05%). O genótipo Lu6 apresentou o menor valor para a digestibilidade in vitro da matéria seca (50,38%). Os teores de digestibilidade da matéria seca e da parede celular foram estimados por método indireto e foram afetados negativamente pelos teores de lignina, ácido p-cumárico e de ácidos ferúlicos totais, que servem de pontes para ligações fortes ou fracas entre ligninas e hemiceluloses. Por meio de análises de regressão múltiplas, verificou-se que a fração fibra em detergente ácido e a lignina em detergente ácido explicaram 98% dos resultados referentes à digestibilidade in vitro da matéria seca e 96% dos resultados referentes à digestibilidade da parede celular estimada por equação. O ácido p-cumárico esterificado e a lignina em detergente ácido explicaram 99% dos resultados referentes à digestibilidade da parede celularChemical-bromatologic composition and in vitro digestibility of five corn genotypes (F2, Lu16, F271, Lu5 and Lu6) were evaluated in Druelle-France, an area of in 150 m2 with two repetitions. All evaluations used whole corn plants without ears. A randomized experimental design was used. The Lu16 genotype showed higher values for in vitro dry matter digestibility (69.82%) and cell wall digestibility (48.05%). Lu6 genotype showed the lowest value for in vitro dry matter digestibility (50.38%). Dry matter and cell wall digestibility were estimated by an indirect method and they were negatively affected by lignin contents, p-coumaric acid and total ferulic acid, serving as strong or weak links between lignin and hemicelluloses. Using multiple regression analysis, results showed that acid detergent fiber and acid detergent lignin explained 98% of in vitro dry matter digestibility results and 96% of cell wall digestibility estimated for equation. Esterified p-coumeric acid and acid detergent lignin explained 99% of cell wall digestibility results

National audience; In order to face new challenges tied to climatic change and the growing scarcity of resources (water, fossil fuels), new dairy systems need to be envisaged. The two main approaches to innovation are discussed based on experiments carried out by the INRA in Lusignan. The first approach, which is analytical, concerns technical innovations (extending the grazing season and new forage crops for producing stocks). More recently, an innovative collaborative and systemic approach was implemented in order to define a new dairy system that challenges the already established one. This new system, as it has been imagined, brings together a new combination of elements by creating a synergy between crop farming and livestock farming. The implementation of this system on a large scale opens the way to innovative approaches in terms of experimentation, indicators and work partnerships.; Pour faire face aux nouveaux enjeux en matière de changement climatique et de raréfaction des ressources (eau et énergie fossile), de nouveaux systèmes laitiers doivent être imaginés. Les deux grandes approches d'innovation ont discutées à partir des expérimentations conduites par l'INRA à Lusignan. La première approche, de type analytique, concerne des innovations techniques (allongement de la période de pâturage et nouvelles cultures fourragères pour la production de stocks). Plus récemment, une démarche d'innovation collaborative et systémique a été engagée pour reconcevoir un système laitier en rupture avec l'existant. Le système imaginé met en cohérence une nouvelle combinaison d'éléments en recherchant des synergies entre cultures et élevage. La mise en œuvre grandeur nature de ce système et son évaluation ouvrent la voie à de nouvelles recherches et à des innovations en matière d'expérimentation, d'indicateurs et de collaboration avec les partenaires.

Prix du public 2014; absent

absent

National audience

El objetivo fue determinar los cambios en rendimiento de materia seca (RMS) y calidad del forraje de sorgo sembrado en surcos distanciados a 75 y 20 cm, y en densidades de 33 y 65 semillas m2, cuando la planta tiene una concentración de materia seca de 300 g kg-1 . No hubo interacción año x distancia entre surcos en los caracteres, excepto en altura de planta. Efecto de año existió, excepto en concentración de materia seca de la planta (322 g kg -1 ) y en proteína (97.6 g kg-1 ). El RMS por año varió de 10 t (2007) a 17 t ha-1 (2009), y de 10 a 16.6 t ha-1 en distancias de 75 y 20 cm, respectivamente. El peso seco de panículas fue 109.4 g y 158.1 g kg-1 mayor en 2007 que en 2008 y 2009, respectivamente, y el peso de mil granos fue 13.66 g kg-1 mayor en 2007 que al promedio de los dos años restantes. La digestibilidad fue 89.5 y 39.9 g kg-1 menor en 2007 y 2008, respectivamente, que en 2009. Hubo correlación entre digestibilidad y cenizas (-0.94**), fibra detergente ácido (-0.93**) y lignina detergente ácido (-0.85*). La proteína fue 15.2 g kg-1 mayor en surcos a 25 cm que a 75 cm. No hubo interacción año x densidad de siembra, ni la densidad afectó el RMS ni la calidad del forraje. El RMS y la calidad del forraje de sorgo fueron mejorados al combinar densidad de siembra de 33 semillas m2 con distancia de 20 cm entre surcos.

Depuis plusieurs décennies, l’évolution de l’agriculture en France est, dans un certain nombre de régions de grande culture et d’élevage marquée fortement par la simplification des assolements accompagnée d’un usage accru des intrants et la standardisation des itinéraires techniques. Le challenge est maintenant de concevoir des agroécosystèmes plus diversifiés dans l’objectif d’une gestion écologique des parcelles cultivées devant se traduire par une amélioration de la productivité et la stabilité des systèmes face à divers aléas et la fourniture de différents services éco-systémiques. Ce projet a exploré l’augmentation de la diversité cultivée au sein de la parcelle via des associations céréale-légumineuse. Il a montré la diversité des services que l’on peut en attendre en agriculture biologique et en agriculture conventionnelle, en système céréalier et en système d’élevage. Ces associations permettent de répondre à la fois à des enjeux de production, de réduction des intrants, de réduction des impacts environnementaux des cultures, de stabilité face à des aléas biotiques et abiotiques. Le coeur du projet a consisté a testé différents leviers d’actions pour aider à l’orientation des performances de ces associations pour différents objectifs. Les atouts et contraintes ’adoption à l’échelle des filières (notamment pour les collecteurs) ont été aussi mis en évidence et quantifiés., We have seen in the last decades in France a great simplification in crop successions in cereal farms and mixed farms with livestock with an increasing use of inputs and a standardization of crop management. The challenge is now to build more diversified agroecosystems through an ecological management of crop areas in order to increase yields and stability and to supply several ecosystemic services. This project has investigated the increase in crop diversity in space within the field through cereal-legume intercropping. Different services may be obtained in organic and conventional farming systems, in cereal and mixed farms with livestock. Intercropping can combine productivity, reduction of inputs, environmental impacts and stability against various biotic and abiotic constraints. Several practices have been tested in order to manage performance of intercrops for different aims. The advantages and constraints for different stakeholders such as collectors have been investigated and quantified.

El objetivo fue comparar el rendimiento de materia seca (RMS) y la calidad de variedades de sorgo de grano y forrajero con o sin nervadura café (bmr), al emplear plantas con concentraciones promedio de 300 g kg-1 de MS. Se estudiaron tres variedades de grano (Solarius, Aralba y Topsilo) y tres forrajeras (Sweet Virginia, Big Kauna y Sucrosorgho). Sweet Virginia and Big Kahuna contienen el gen bmr. El RMS varió de 11.10 t, de Topsilo, a 17.12 tha-1 de Sweet Virginia, relacionada con la altura de planta y con la proporción tallo/planta. Topsilo tuvo mayor número de rebrotes (1.5 m-1). La relación panícula/planta no fue diferente entre variedades. El número de plantas m-1 varió entre variedades pero no afectó el RMS. La concentración de proteína varió de 75.45 g kg-1 MS en Big Kahuna, a 104.3g kg-1 MS en Solarius, y tuvo relación inversa con el RMS, con la altura de la planta y con la relación tallo/planta. Las variedades con mayor concentración de proteína (Solarius, Aralba y Topsilo), fueron las de menor RMS, menor altura y menor relación tallo/planta. El área foliar por planta fue la fuente de variación de la proteína entre las variedades de grano. La digestibilidad varió de 596 g kg-1 MS en Aralba, a 720.4 g kg-1 MS en Sweet Virginia, y estuvo relacionada con la concentración de lignina. Esta última variedad junto con Big Kahuna y Solarius fueron las de mayor digestibilidad. La alta digestibilidad de Solarius (no portador de bmr) se debió a su baja proporción (0.35) tallo/planta. La variedad Sweet[br/] Virginia es una importante opción en la alimentación animal dado a su elevado RMS y digestibilidad. Solarius tuvo bajo RMS, pero es útil cuando se requieren altos consumos de materia seca digestible por animal (vacas lecheras), además de contar con la mayor concentración de proteína., The aim was to compare yield of dry matter (RMS) and quality of grain and foliage sorghum varieties with and without brown midrib (bmr), by using plants with average concentrations of 300 g kg-1 of DM. Three grain (Solarius, Aralba and Topsilo) and three forage (Sweet Virginia, Big Kauna and Sucrosorgho) varieties were studied. Sweet Virginia and Big Kahuna contain bmr gene. RMS varied from 11.10 t, of Topsilo, to 17.12 t ha-1 of Sweet Virginia, related with plant height and stem/plant proportion. Topsilo had greater number of sprouts (1.5 m-1). Relationship panicle/plant was similar between varieties. Number of plants m-1 had variation between varieties but did not affect RMS. Protein concentration was from 75.45 g kg-1 DM in Big Kahuna, up to 104.3 g kg-1 DM in Solarius, and had inverse relationship with RMS, with plant height and with stem/plant ratio. Varieties with greater protein concentration (Solarius, Aralba and Topsilo), showed least RMS, lower height and lower ratio stem/plant. Foliar area per plant was source of protein variation between grain varieties. Digestibility ranged from 596 g kg-1 DM in Aralba, up to 720.4 g kg-1 DM in Sweet Virginia, and was related with lignin concentration. This last variety with Big Kahuna and Solaris were the best in digestibility. The high digestibility from Solarius (not bmr carrier) was because its low stem/plant ratio (0.35). Sweet Virginia variety is an important option in animal food since its high RMS and digestibility. Solarius had low RMS, but is useful for high consumption of digestible dry matter (dairy cows), also has better protein concentration.

Recherche de systèmes fourragers innovants : économie d'eau et d'énergie, contribution au stockage du carbone

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National audience

Objetivou-se avaliar as características morfo-anatômicas de cinco genótipos de milho normais (F2, Lu16, F271, Lu5 e Lu6) e cinco bm3 (F2bm3, Lu16bm3, F271bm3, Lu5bm3 e Lu6bm3) com inferência à qualidade para silagem cultivados em Druelle-França, em parcelas de 150 m² durante o período de maio a setembro de 2002 (150 dias). Todas as avaliações foram realizadas no entrenó abaixo da espiga principal. O delineamento experimental utilizado foi o inteiramente casualizado com cinco repetições por tratamento. Os genótipos apresentaram diferenças significativas quanto aos aspectos anatômicos, sendo que todos os genótipos bm3 apresentaram menores quantidades de células lignificadas tanto na região medular (1,24) quanto na região do córtex (1,72). Observou-se correlação positiva (r= 0,70) entre a quantidade de células lignificadas da região medular e a porcentagem de região medular. Também houve correlação positiva (r= 0,67) e negativa (r= -0,67), entre a espessura da parede celular com a % de xilema e com a % de floema, respectivamente. Os resultados encontrados estão coerentes aos tipos de linhagens estudadas, pois as linhagens bm3 são caracterizadas por apresentarem menores proporções de lignina quando comparados com genótipos normais., The objective was to evaluate the morphoanatomical characteristics of ten genotypes of corn to silage, five normal (F2, Lu16, F271, LU5 and LU6) and five bm3 (F2bm3, Lu16bm3, F271bm3, Lu5bm3 and Lu6bm3), grown in Druelle-France, in plots of 150 m² during the period from May 2002 to september 2002, totaling a period of 150 days. All evaluations were performed in internode below the primary ear. The experimental design was completely randomized, with five replications per treatment. The genotypes showed significant differences on the anatomical aspects evaluated, and that all bm3 genotypes showed lower amounts of both lignified cells in the medullar region (1.24) as in the cortex (1.72). The statistic analysis pointed positive correlation (r= 0.70) between the amount of lignified cells in the medullar region and the percentage of medullar region. There was also positive correlation (r= 0.67) between the thickness of the cell wall with the xylem % and negative correlation (r= -0.67) between the thickness of cell wall with the phloem %. The results are consistent to the types of strains studied, because the bm3 lines are characterized by smaller proportions of lignin compared to normal genotypes.

Objetivou-se avaliar os efeitos das silagens de sorgo granífero, sorgo sacarino e milho sobre a ingestão, produção e composição química do leite e a digestibilidade dos nutrientes em vacas em lactação. Foram utilizadas 24 vacas da raça Prim'Holstein (PO), divididas em três lotes de oito vacas para avaliação das seguintes silagens: silagem de milho (SM); silagem de sorgo granífero (SG); e silagem de sorgo sacarino (SS). As silagens foram fornecidas à vontade com dois concentrados comerciais, distribuídos de acordo com o nível de produção leiteira. A silagem de sorgo granífero promoveu maior ingestão de MS (22,98 kg/dia) em comparação às silagens de milho (21,95 kg/dia) e de sorgo sacarino (19,43 kg/dia). A ingestão de água (litros/vaca/dia) foi semelhante entre os animais alimentados com silagem de milho (71,91) e de sorgo granífero (76,30) e menor nos animais alimentados com silagem de sorgo sacarino (56,95). A produção de leite total (28,81; 24,69 e 24,14 kg/dia) corrigida a 4% de gordura (30,65; 25,63 e 26,10 kg/dia) foi maior entre as vacas alimentadas com silagem de milho, no entanto, a porcentagem de gordura do leite das vacas alimentadas com silagem de sorgo sacarino foi maior (4,56%) em comparação àquelas alimentadas com silagem de milho (4,39%) e silagem de sorgo granífero (4,31%). A porcentagem de proteína foi maior (3,25%) no leite das vacas alimentadas com silagem de milho, intermediária no leite das vacas alimentadas com silagem de sorgo sacarino (3,05%) e menor no leite das vacas alimentadas com silagem de sorgo granífero (2,97%). Os coeficientes de digestibilidade dos nutrientes foram maiores nas vacas alimentadas com a ração à base de silagem de sorgo sacarino em comparação às rações à base de silagem de sorgo granífero e de milho. The effect of feeding grain sorghum silage, sweet sorghum silage, and corn silage on intake, milk production, milk composition, and nutrient digestibility of lactation dairy cows was evaluated. Twenty-four Prim'Holstein (PO) cows were used, forming three groups of eight cows each. The experimental treatments were: 1) corn silage; 2) grain sorghum silage; and 3) sweet sorghum silage, fed ad libitum, with two commercial concentrates, distributed following the cow milk production. Grain sorghum silage promoted greater DM intake (22.98 kg/day) compared to corn silage (21.95 kg/day), and sweet sorghum silage (19.43 kg/day). Dry matter intake was greater for corn silage than for sweet sorghum silage. Water intake (L/cow/day) was similar for the animals fed corn silage (71.91) and grain sorghum silage (76.30), and both were greater than the water intake of animals fed sweet sorghum silage (56.95). Total milk production (28.81; 24.69 and 24.14 kg/day), 4% fat corrected milk (30.65; 25.63 and 26.10 kg/day), and milk chemical composition was greater for cows fed corn silage when compared to the ones receiving grain sorghum silage and sweet sorghum silage. Cows fed sweet sorghum silage, but showed higher milk fat percentage (4.56%) compared to cows fed corn silage (4.39%) or grain sorghum silage (4.31%). Milk protein concentration was higher for cows fed corn silage (3.25%), intermediate for cows fed sweet sorghum silage (3.05%), and lower for the ones fed grain sorghum silage (2.97%). Nutrient digestibility coefficients were greater for cows fed sweet sorghum silage compared to other silages.

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International audience; In sustainable agriculture, adaptation of swards to grazing is a major issue for breeding forage grass cultivars. Understanding the relationships between sward traits and animal production under grazing could help to identify criteria for selection. Intake is the major limiting factor for animal production under grazing. In this paper, short-term intake rate by grazing dairy cows (Bos taurus) is compared between eight diploid perennial ryegrass (Lolium perenne L.) populations. Four replicates per population were measured over four periods (April and May 2001, and April and October 2002) in two experiments per period, that is, intermediate- and late-maturity groups. For each period, sward structure was characterized by tiller density, leaf blade and sheath lengths, and green leaf and total dry matter (DM) yield, while nutritive value was characterized by in vitro dry matter digestibility (IVDMD), percent of DM, N, water-soluble carbohydrate (WSC), and neutral-detergent fiber (NDF) contents. For the latematurity populations, the population with the shortest leaves had a lower fresh matter intake rate (10.5 kg h21) than the three others (12, 12, and 11.6 kg h21, respectively). For the intermediate-maturity populations, differences in intake rates among populations were significant (P 5 0.06) for all periods and were highly significant (P, 0.0004) in April 2002. In this period, 49% of the variation in fresh matter intake rate could be explained by blade length. In conclusion, differences in short-term intake rate between populations of diploid perennial ryegrass are highlighted. In both maturity groups, blade length appears to be an important factor explaining these differences.

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Two experiments were conducted to evaluate performance and physiological responses of heifers and lambs to Neotyphodium coenophialum-infested tall fescue hay fed under European rearing conditions. Endophyte-free (E-) or 100% endophyte-infested (E+) hay was derived from the same cultivar (cv. Clarine) so that the effect of the endophytic fungus could be clearly separated from a possible cultivar effect. In Exp. 1, starting in June 1996, 20 age- and body weight-paired Holstein dairy heifers were assigned for 97 d to one of two treatments consisting of ad libitum access to either E- or E+ hay, corresponding to 0 and.41 mg/ kg ergovaline, respectively. During the experimental period, no significant difference (P >.20) in forage consumption, rectal temperature, or behavioral status of the animals was observed between the two treatments. The E+ diet induced a 10% apparent decrease in ADG and a clear reduction in prolactin (PRL) plasma concentration compared to the E- diet. When animals were all reassigned to a common endophyte-free diet, the E+ group recovered body weight and PRL to levels similar to those in animals fed E- after 7 wk. In Exp. 2, 30 Texel ram lambs were assigned to two treatments consisting of dietary E- or E+ tall fescue hay. The E- and E+ hays were harvested from the same plots as used in Exp. 1 and contained 0 and.96 mg/kg ergovaline, respectively. No effect of the endophyte was found on intake or carcass or testicle weight (P >.20) after the 95-d feeding period. The E+ treatment resulted in a slight reduction in BW at slaughter, mainly explained by a lower ruminal fill (P

Au cours de 4 années d’expérimentation avec des vaches laitières, différents hybrides de maïs choisis pour leur valeur énergétique mesurée sur moutons standards ont été comparés en ensilage de la plante entière. Les hybrides dont la valeur énergétique estimée sur les moutons était la plus élevée permettent des productions de lait standard supérieures de 1 à 2 kg et des reprises de poids pouvant atteindre 300 g de plus par jour. Les écarts de quantités de matière sèche d’ensilage ingérées ont également atteint 1,5 kg à teneur en matière sèche et teneur en grain constantes. Si les mesures faites sur moutons, comme les mesures de solubilités enzymatiques, permettent nettement de distinguer les hybrides à bonne valeur énergétique des hybrides à faible valeur énergétique, elles ne permettent en revanche pas de classer correctement les hybrides au sein de chacun de ces deux groupes. Enfin, aucune des mesures effectuées sur moutons ou in vitro ne permet de prédire la variabilité observée pour l’ingestibilité., Genetic variation in the feeding efficiency of different maize genotypes was evaluated from experiments with dairy cows. The maize genotypes were chosen according to their variable digestibility range, determined in previous experiments with standard sheep. The variations in milk yield observed with dairy cows fed a low, respectively a high, digestible or energizing hybrid were between 1 to 2.0 kg per animal, per day. Moreover, the differences in body weight gain reached up to 300 g per day. Hybrids having similar energy values acted similarly on milk yield, but the intake could be very different when fed to dairy cows, even if no difference in intake was observed in sheep measurements. The 1.5 kg higher silage maize intake of DK265 was mostly converted into a body weight gain, and not in increasing the milk yield, probably because the milk yield potentiel of the animals was soon reached. It appeared that the hybrids which had a low predicted energy value from the sheep measurements also had a lower performance in cows. Dairy cow performances also appeared to concur with the enzymatic solubility values of the whole plant. However, only good hybrids could be distinguish from poor ones, but the variation within good, respectively poor, hybrids could not reliably be investigated with the enzymatic solubility test used. The variation in ingestibility could not be predicted. For maize breeders, the prediction of an hybrid efficiency for use in dairy cow rearing must include digestibility and ingestibility factors. Enzymatic processes could probably be used to avoid drift towards poor feeding values with hybrids bred for a higher stalk strength. The most important challenge for maize breeders will most likely be the determination of a criterium for the intake prediction. The stover digestibility and starch content can be reliably predicted through the use of NIRS (near infra-red reflectance spectroscopy) calibrations. For a stock-breeder, a pertinent choice of a maize hybrid might allow significant concentrates and money saving.

International audience; Based on in vitro results, common ash (Fraxinus excelsior) and white mulberry (Mores alba) could serve as a useful form of alternative forage during the dry part of the summer, when grass resources are lacking. To better understand the forage potential of these two species, we formed two experimental groups of six adult sheep in their maintenance phase. Each group was offered leaves from one species ad libitum. A third group of six sheep was fed hay from a permanent grassland. For three weeks, we measured forage intake and digestibility. We found that the sheep consumed large quantities of the leaves, which were well digested. Thanks to their low fibre content, the leaves could be fed to animals with high resource needs, whether during the growth stage or the production stage. Future research should examine the forage potential of additional tree species found in temperate zones.

Les arbres font partie intégrante de nos paysages ruraux, qu’ils soient localisés dans les parcelles agricoles (alignements, arbres isolés) ou à leur périphérie (bois, bosquets, haies). Les relations entre arbres et agriculture, souvent conflictuelles jusque dans un passé récent, peuvent être aujourd’hui envisagées de manière renouvelée selon les principes de l’agroécologie, notamment sur la base d’associations d’une large gammed’espèces présentant des complémentarités aux échelles de la parcelle et du paysage. Cette plaquette présente les orientations de recherches sur les produits et les services issus de l’agroforesterie où les arbres sont intégrés dans les pratiques agricoles mais aussi dans les politiques publiques, comme celle du “produire autrement” en France.

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Les dispositifs expérimentaux mis en place permettront d’étudier différentes espèces, organisations spatiales et types de protection vis-à-vis du troupeau, ainsi que plusieurs modes d’exploitation de ces ressources ligneuses. La valeur nutritive des feuilles collectées en été sur 27 espèces ligneuses fait l’objet d’une large évaluation (valeur énergétique et azotée, teneur en fibres et en tanins condensés, digestibilité, dégradabilité théorique de l’azote). Plusieurs espèces présentent un excellent profil pour leur valeur protéique et énergétique : le mûrier blanc et le frêne, mais aussi le tilleul, l’aulne de Corse et un certain nombre de lianes et d’arbustes. D’autres espèces conviendraient également pour alimenter en été, et par le pâturage, des animaux à l’entretien ou aux besoins plus modérés que des animaux en lactation., Can forage systems exploit trees, shrubs, and lianas, particularly during summer grazing? This study discusses the approaches being used at the INRA center of Lusignan to combine agroforestry and dairy livestock farming. Researchers are examining different species, spatial organisation systems, and means of protecting herds, as well as exploring multiple ways of exploiting woody resources. The first results for nutritional quality (i.e., of leaves collected in the summer) show that a great deal of variability exists among the 27 study species. They also highlight the attractiveness of certain tree species, such as the white mulberry (Morus alba), the ash (Fraxinus excelsior), the common linden (Tilia platyphyllos), and the Italian alder (Alnus cordata), as well as of certain shrubs and lianas. Other species could also be used to feed specific types of grazing animals in the summer, namely those on maintenance diets or with more modest needs (i.e., non-lactating animals).

National audience

National audience

The feeding value of maize silage, which is equal to the product of the voluntary intake by the digestibility, is the main factor influencing the performance of livestock. It is necessary to study the sources of its variation and show the factors responsible for the quality of forage maize in order to breed to-morrow's cultivars. For 34 years, from 1958 to 2002, 2383 measurements of digestibility of maize silage were carried out on 478 hybrids at the INRA station in Lusignan. These measurements, made with standard castrated rams, concerned all types of hybrids : early heading, late heading, registrated, experimental, and also bm3 mutants. Results show a very large variation in the energy value of the silages, linked to the hybrid utilized, and under the strong influence of cell-wall digestibility (CUDndf). On average, the energy value of maize is 0.89 UFL (fodder unit fort milk), but the measured values ranged from 0.74 to 1.01 UFL. Various comparisons showed for instance that the early-heading hybrids are more digestible than the late heading ones, and that the more recent cultivars are on average less digestible than the old ones. Lastly, new tools for the prediction of the in vivo digestibility of the organic matter, or of the NDF, should give the breeders the possibility of creating cultivars with better feeding values.; L'ensilage de maïs est largement utilisé pour l'alimentation des ruminants à haut potentiel ; sa valeur alimentaire est le principal facteur influençant les performances des animaux. L'étude des sources de variation et la mise en évidence des critères qui conditionnent la qualité des maïs fourragers est nécessaire pour sélectionner les variétés de demain. Pendant 34 ans, 2 383 mesures de digestibilité d'ensilages de maïs portant sur 478 hybrides ont été réalisées à l'INRA de Lusignan. Ces mesures avec moutons castrés standards ont porté sur tous les types d'hybrides : précoces, tardifs, inscrits, expérimentaux ou encore mutants bm3. La variabilité de la valeur énergétique des ensilages est très importante et elle est fortement conditionnée par la digestibilité des parois (CUDndf). Si le maïs a une valeur énergétique moyenne de 0,89 UFL, les valeurs mesurées vont de 0,74 à 1,01 UFL. Les hybrides précoces sont plus digestibles que les hybrides tardifs ; les variétés récentes sont en moyenne moins digestibles que les variétés anciennes. Enfin, la mise au point d'outils de prédiction de la digestibilité in vivo de la matière organique ou du NDF, utilisables en routine, devraient permettre aux sélectionneurs de proposer des variétés avec des valeurs alimentaires plus élevées.

This chapter reviews knowledge on the agronomy, genetics, feeding value and harvestingmethods used for lucerne (alfalfa; Medicago sativa), which is the temperate climate legumespecies with the highest protein yield. It has agronomic advantages (high forage production,adequate persistency and drought tolerance) and provides a high quality feed forruminants. Lucerne also has positive impacts on the environment such as soil structure,nitrogen fertility, carbon storage, and plant and animal biodiversity. Lucerne productionsupports sustainable farming systems. Besides seed production that generates significanteconomic activity, novel uses of lucerne for human or animal health or energy productionare also being investigated. Proposals for measures to increase lucerne cultivation in Europeanfarming systems are provided.

National audience; Dairy systems based on grazing reach their highest economic performance when utilized as much as possible under grazing. Standing crops make it possible to control the costs by reducing the proportion of harvested forage. This technique is presently well mastered with Perennial Ryegrass. Measurements of the quality of this type of forage are welcome. From 1999 onwards, cultivars of Perennial Ryegrass were grown as standing crops. Three samplings, made after 21, 42, and 63 days of regrowth, showed how the quality of the forage changed with time. This quality was assessed by measuring the disappearance of the dry matter in the rumen after 9, 24, or 72 hours of incubation. The results showed that with this management of delayed grazings there existed a genetic variation for digestibility among the Perennial Ryegrass cultivars ; that there could also exist differences in voluntary intake ; and there was a considerable effect of the type of grazing management on the quality of the forage.; Les systèmes laitiers basés sur le pâturage sont économiquement performants lorsque le pâturage est maximisé. Les stocks sur pied permettent la maîtrise des charges en réduisant la part des fourrages récoltés. Cette technique est aujourd'hui maîtrisée avec du ray-grass anglais. Des mesures sur la qualité de ce type de fourrage sont les bienvenues. En 1999, 4 variétés de ray-grass anglais ont été conduites en stocks sur pied. 3 prélèvements à 21, 42 et 63 jours de repousse ont permis de suivre l'évolution de leur qualité. La qualité a été appréhendée à travers la méthode de disparition de la matière sèche après 9, 24 ou 72 heures d'incubation dans le rumen. Les résultats ont montré que, avec ce mode de report, il existe une variabilité génétique pour la digestibilité entre les variétés de ray-grass anglais, qu'il pourrait y avoir des différences d'ingestibilité et que le mode d'exploitation de la pâture influe considérablement sur la qualité du fourrage.