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Nitrogen is known to be the limiting factor of productivity in organic systems. In low-input organic, mixed-crop dairy systems (MCDS) at the Mirecourt INRA station, studies are conducted on the contribution of associated cereal/protein-rich plant crops and concentrate mixes to the nitrogen self-sufficiency of the system. An agronomic and zootechnical analytical trial was established with nine types of cereal and protein-rich plants, and associated cereal/protein-rich plant crops were compared in plot trials in 2006 and 2007. The valorization of three cereal/protein concentrate mixes by 24 lactating dairy cows was tested in a zootechnical experiment during winter 2007. Dairy cows were each fed 4 kg d-1 of the mix, 8kg DM d-1 of lucerne/cocksfoot hay, and permanent grassland hay ad libitum. Associated cereal/protein rich plant crops produced a greater and more stable yield (3.0 t ha-1) that pure cereals (2.2 t ha-1) but the proportions of protein rich grains in the mixes were highly variable (26 to 62%). Dairy cows' feed requirements were satisfied by the three diets. Cereal/protein concentrate mixes had a low impact on dairy cows' performance because of the high contribution of forages to the diet.

Nitrogen is known to be the limiting factor of productivity in organic systems. In low-input organic, mixed-crop dairy systems (MCDS) at the Mirecourt INRA station, studies are conducted on the contribution of associated cereal/protein-rich plant crops and concentrate mixes to the nitrogen self-sufficiency of the system. An agronomic and zootechnical analytical trial was established with nine types of cereal and protein-rich plants, and associated cereal/protein-rich plant crops were compared in plot trials in 2006 and 2007. The valorization of three cereal/protein concentrate mixes by 24 lactating dairy cows was tested in a zootechnical experiment during winter 2007. Dairy cows were each fed 4 kg d-1 of the mix, 8kg DM d-1 of lucerne/cocksfoot hay, and permanent grassland hay ad libitum. Associated cereal/protein rich plant crops produced a greater and more stable yield (3.0 t ha-1) that pure cereals (2.2 t ha-1) but the proportions of protein rich grains in the mixes were highly variable (26 to 62%). Dairy cows' feed requirements were satisfied by the three diets. Cereal/protein concentrate mixes had a low impact on dairy cows' performance because of the high contribution of forages to the diet.