Eco-efficiency of grass-based dairy systems in Switzerland.

Grassland covers 70% of the Swiss agricultural area, resulting in a large proportion of grass in the diet of Swiss dairy cows. In recent years, an increase in milk yield has been achieved, which has led to an increasing use of concentrates. The Federal Office for Agriculture has started to subsidize the inclusion of a large proportion of grass in the ration of ruminants. In two studies we assessed the environmental performance of dairy systems with different proportions of grass in the ration, by life cycle analysis according to SALCA. The comparison of the Swiss dairy system, with low use of concentrates, with systems in France, Germany and Italy showed that despite the lower milk yield and concentrate input, the Swiss system performed equally or better in all environmental impacts analysed, with the exception of land use. In the comparison of an intensive and a pasture-based dairy system within Switzerland the pasture herd performed equally or better for most environmental impacts with the exception of global warming, ozone formation and land occupation. This shows that despite the lower milk yield, grass-based systems can be eco-efficient.