Measurement methods on pastures and their use in environmental life-cycle assessment

Summary

Grassland is an important and energy extensive feed source for livestock and good pasture management is required to maintain its productivity. Due to the selective grazing behavior of dairy cows and site and management related sward variability it is difficult to estimate pasture yield or pasture intake. A proper estimation of feed intake of animals on grassland enables the farmer to appropriately manage his pastures. Measurements of the variable feed offer at pasture plots with a rising plate meter are relatively quick. They offer a data basis to improve grazing and pasture management. These data are also used to describe material flows from grassland. On the explored pasture plots high differences in the dry matter intake of the cows were found. Optimizing pasture yields, e. g. by sward improvements and grazing management, offers chances to reduce environmental burdens of milk production. Environmental impacts of an improved grazing management based on the whole farm process are calculated with the flow model FARM that is designed to conduct life cycle assessments (LCA) of farm products. Every kg DM grass silage that is substituted by grazing intake reduces the global warming potential of milk production. Site specific potential was 1.5 % per kg ECM. Further reductions by improving feeding management and food quality are anticipated.