Unterschiedliche Fütterung: Treibhausgaslast der Milch von vier Milchviehbetrieben

Summary

Four organic dairy farms of a German farm network (www.pilotbetriebe.de) were described in detail with respect to average diets and feedstuff quality, and were compared to the mean results of the 22 organic and 22 conventional farms of the network. At milk yields between 4,469 and 6,769 kg energy corrected milk (ECM) a-1, rations of three farms almost completely depended on grass and grass clover from both grassland and arable land (96-100 %; mean organic approx. 75 %). The fourth farm was similar to the average conventional milk yield and diet (incl. maize silage and a high share of concentrates) hence it largely depended on arable land. Enteric methane (CH4) emissions per kg ECM were higher the more fibre rich feedstuffs were fed and, as expected, the lower the milk yield. The composition of excreta (determining the potential to emit greenhouse gases, GHG) is also a result of the interaction of feed intake, feed quality and feed components on the different farms. The various factors that impact on emissions from dairy cows, from their stable and pasture environment and from storage of their manure can considerably be influenced via feeding and the related milk yield. Trade offs in other farm sections and outside the system boundaries (such as animal health and welfare, soil organic carbon, etc.) have to be considered when optimising dairy systems to reduce GHG.