Niderkorn V., Martin C., Rochette Y., Julien S., Baumont R. Synergy between cocksfoot and red clover silages on voluntary intake and digestive processes in sheep Niderkorn V., Martin C., Rochette Y., Julien S., Baumont R. INRA Clermont-Ferrand-Theix centre 24th General Meeting of the European Grassland Federation 2012 , Lublin, Poland June 3rd – June 7th

Introduction Grass-legume associations Agronomic and environmental interests Interactions between grass and legume species on intake and digestion in ruminants When the ingestive and digestive profiles of a combination of forages differ from the balanced average values of pure plants (synergism, antagonism) Could synergistic effects be observed to increase performances and feed efficiency ? Increasing voluntary intake and/or improving nutrient use in the animal

Introduction Associative effects on voluntary intake Mode of action Voluntary intake can be higher when grass/legume associations are fed compared to grass alone (e.g. Reid et al., 1987) Magnitude of associative effects on DM intake varies among the mixed plant species, the mode of conservation and the proportion of legume (Niderkorn and Baumont, 2009) Mode of action Unclear: changes in the passage rate through the rumen, extent of digestion, increase in the motivation to eat mixtures compared to monocultures ? Multisward Testing several grass-legume models with different species and modes of conservation during 3 years

Objective of the study To bring a comprehensive knowledge of the associative effects between grasses and legumes on intake and digestion in sheep Cocksfoot Red clover Methane emissions Intake behaviour DM digestibility

EXPERIMENTAL DESIGN Feeding experiment using ruminally cannulated sheep Binary mixtures of silages of cocksfoot (cv Starly) and red clover (cv Diadem) Five proportions (100:0; 75:25; 50:50; 25:75; 0:100) Latin square 5 × 5 repeated Day 1 10 Adaptation period 11 12 Measurement period 13 14 Methane emissions (SF6) DM digestibility 8 9 Kinetics of intake and chewing activity Chemical composition of plants Housing in metabolic crates Weighing

Chemical composition of silages RESULTS Chemical composition of silages Cocksfoot Red clover P-value Dry matter (g kg-1) 470 305 <0.001 Crude protein (g kg-1 DM) 156 187 Fibre NDF 461 401 ADF 257 246 <0.01 ADL 31 50

Daily voluntary intake RESULTS Daily voluntary intake Daily DM intake +11.5 % ab a b c Daily NDF intake a a a b +9.5 % c Quadratic effect (P < 0.001) Why this synergy ? Digestive interaction ? Greater motivation to eat a mixture ?

Daily intake of the digestible fraction RESULTS Quadratic effect (P < 0.001) Daily intake of the digestible fraction b c ab a +10 % Digestibility a ab ab ab b Linear effect (P < 0.01)

Indicates a greater motivation to eat the mixture 50:50 RESULTS Daily eating rate a Indicates a greater motivation to eat the mixture 50:50 ab b +6 % b b Quadratic effect (P < 0.01)

RESULTS Methane emissions a a a a b Linear effect (P < 0.001)

Conclusion A synergy between cocksfoot silage and red clover silage can be observed in sheep on all the parameters of intake behaviour such as DM, NDF and digestible DM daily intake and eating rate. Synergy optimal for proportion 50:50 Synergy rather due to a greater motivation to eat than a more efficient digestion - no associative effect on digestibility No associative effect on methane emissions but a lower value with pure red clover

Thank you for your attention 24th General Meeting of the European Grassland Federation 2012 , Lublin, Poland June 3rd – June 7th