1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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 ?

8. 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)

9. 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)

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

11. 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

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