Effect of REE on performance parameters A detailed description of the REE effects on performance parameters is published by Schwabe et al. (2011). In this paper only the major results of the performance are summarised (see Table 3). The grass silage intake remained unaffected by the REE treatments, whereas the grass hay intake linearly decreased with increasing REE supplementation in the growing period (p=0.030). The concentrate intake was slightly stimu-lated due to REE supplementation (p=0.084) and showing a significant quadratic effect (p=0.025). The total feed intake linearly declined (p=0.042) in the growing period which can be explainedwith the reduced grass hay intake. In the fattening period the maize silage intake was significantly reduced by 10.7% in Group D compared to the control group and showed a significant linear decrease (p=0.001). In addition, the bulls of Group D had a significantly lower concentrate intake (p=0.034) in comparison to Group C. As a consequence of declined maize silage and concentrate intake, the total feed intake of Group D was significantly lower than those of Group A (Table 3). However, over the whole feeding trial neither live weight gain nor the feed-to-gain ratio and the metabolisable energy-to-gain ration were significantly influenced by the REE treatment (Table 3).