Use of farm grown cereal/protein mixes by lactating dairy cows in a winter diet

We 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

Assessing the agro-environmental sustainability of organic mixed-crop dairy systems on the basis of a multivariate approach

Sustainable development calls upon the farming sector to commit itself to the transmission of natural resources to future generations. The INRA research team of Mirecourt studies the design of environmentally-friendly farming systems. The design of these systems is based on a multitude of objectives, and their evaluation is determined by a wide range of criteria. This work aims at determining the practical conditions for implementing agricultural systems considered to be sustainable from an environmental point of view. Two organic dairy systems considered to be environmentally friendly ex ante have been designed in partnership with the staff of the INRA research team of Mirecourt. A grazing dairy system and a mixed-crop dairy system are being experimentally tested at the system scale. The two systems have environmental and agricultural objectives. They are managed using multi-objective decision rules and are assessed on their biotechnical and practical properties, using a structured multiyear experimental design, completed by a model-based assessment. Assessment is oriented towards progressive and permanent re-designing of the systems in order to increase their environmental sustainability and feasibility at the practical level. Knowledge acquired from the two prototypes will then have to be validated on commercial farms