Use of farm grown cereal/protein mixes by lactating dairy cows in a winter dietCOQUILauthorTROMMENSCHLAGERauthorBAZARDauthorDESPRESauthorDELABYauthorWe compared the use of three farm grown cereal/protein mixes (oat/fava bean, barley/lupin, triticale/pea), that were used to complement lactating dairy cow diets based on hay consisting of alfalfa/orchard grass and perennial grassland. The trial took place in 2007 at the INRA experimental station of Mirecourt, where an organic mixed-crop dairy system is being prototyped. The experiment was carried out in a Latin square with three groups of eight cows (50% Holstein, 50% Montbéliarde). The cows were fed 4 kg/cow/day of one of the three cereal/protein mixes, 8 kg DM/cow/day of alfalfa/orchardgrass hay, and permanent grassland hay ad libitum. The three diets were indicative of the animals’ needs. Diets had no significant effect on milk production (20.3 kg/cow/d) and milk fat content (41.3 g/kg). However, dairy cows fed with the oat/fababean mix had a significantly lower protein content in their milk. This is the result of: (i) a nitrogen surplus in relation to energy, and (ii) a lower starch content compared to the two other diets. Therefore, in organic mixed-crop dairy systems with forages that are rich in nitrogen, the choice to cultivate mixtures of cereal/pulses and the composition of these mixtures must be primarily based on their agronomic interest and not on their zootechnical one since they are not essential to a balanced animal diet. Dairy cattle Feeding and growth2009-01INRAJournal paper