Production efficiency, costs and environmental impacts of conventional and dynamic forage systems for dairy farms in Italy

Over the last few decades, scientists, decision-makers, consumers and the more volatile marketplace impose to dairy farms to manage forage systems more sustainably, while maintaining profitability. Hence, shifting from a conventional forage system based mainly on monocropping corn (CONV_FS) to a more flexible one, defined as dynamic forage system (DYN_FS), that is based on increasing on-farm cropping of leguminous species, double cropping, scheduling of forage cuts to early stages of growth, and the adoption of silage conservation in place of haymaking, could help increasing overall system sustainability. A multi-year study, conducted on two commercial high productive dairy farms, analyzed this shift from an agronomic, economic and environmental point of view. The two farms milked 127 and 262 cows, farmed 56 and 102 ha, and had a milk production intensity of 20 and 26 t/ha per year, respectively. All the data necessary to determine dry matter (DM) yield, forage quality, in terms of crude protein (CP) and metabolizable energy (ME), the nitrogen balance, agrochemical management, the energy balance and efficiency, labor use, economic budgets, and carbon footprint of the two forage systems were on farm measured and collected. One hectare of tillable land, 1 t of DM or CP, and 1 GJ of ME were chosen as functional units. The adoption of DYN_FS increased overall system efficiency (increased DM, CP and ME yields per hectare), reduced reliance on external inputs (chemical N and pesticides), led to a more equilibrated N balance, reduced agrochemical use intensity and potential ecotoxicological impacts, increased energy use efficiency and reduced carbon footprint when compared to CONV_FS. Shifting from DYN_FS to CONV_FS had also a positive effect on the costs sustained per hectare of tillable land, whereas the labor requirements increased slightly on a per hectare basis, but decreased relative to the chosen functional units. Finally, DYN_FS provided more ME and CP than CONV_FS, but maintained a similar milk production and quality. We have concluded that the new dynamic forage system DYN_FS has the potential of being profitable and could enhance production efficiency and environmental quality in the more intensive forage systems adopted on dairy farms in the Po plain in Italy.