Sustainable intensification of dairy farms in temperate Atlantic climate; effects on productive, nutritional and environmental aspects

CONTEXT

Animal diet, farm management, and feed production are factors that need to be considered in order to maximize the efficiency and minimize the environmental impacts of dairy farms. Sustainable forage intensification could be one possible solution in order to maintain food security and profitability and at the same time respect the environment under the threat of climate change.

OBJECTIVE

This work simulates the productive, nutritional, and environmental effects of cattle dairy farms in wet temperate regions of North Spain, under sustainable intensification. This approach was based on forage intensification by converting grassland areas to annual forage crops and replacing the concentrate intake in dairy cows' diet by up to 30 %, with silage from the forages produced on-farm.

METHODS

Two intensive dairy systems were used, identified according to the herd's diet composition. A model farm that represents an average farm in each of the two characteristic intensive systems was employed, taking into consideration field area and use, number of animals, diet, milk yield and slurry management. The simulation model DairyCant was used to run simulations of the average farms under present management (baseline) and under scenarios over succession of Zea mays L. to various winter forage crops (7 scenarios), with variation of the number of dairy cows in the herd (7 scenarios) and under partial replacement of concentrate in the herd's diet (14 more scenarios), resulting to 28 simulations for each intensive dairy system.

RESULTS AND CONCLUSIONS

Using forage intensification, the production of forages was increased and as a consequence, feed imports are reduced, thus feed production is relocated and farmers' profitability could be increased. Besides, the environmental factors, such as the nitrogen (N) surplus and the total N footprint were decreased, indicating that would have the potential to reduce farm GHG emissions and nitrogen losses. The scenarios involving Z. mays L. succession to Trifolium incarnatum were the most interesting, from a productive, nutritional and environmental point of view.

SIGNIFICANCE

Replacing grassland with annual forage crops and reducing concentrate intake of dairy cows could result to increase of the nitrogen use efficiency, which means less nitrogen excreted to the environment. At the same time, the reduction of the concentrate provides the potential to improve the economic sustainability of the farms. To establish the realistic implementation of the forage management described here, farmers' abilities and willingness, together with potential supportive policies, must be taken into account.