We conducted two conditioning experiments to investigate whether sheep are able to develop preferences of aversions in response to an increase of rumen fill performed with 300 or 600 g chopped straw introduced through the rumen fistula. When sheep where fed a basal diet of hay (Experiment 1) they developed aversions against the feeds associated with the increase of rumen fi ll without a dose effect. When they were fed a diet of pellets of beet pulp (Experiment 2) they developed neither preferences nor aversions. These results indicate that physical consequences of feed intake are integrated by the animals and that they can contribute to diet choice via diet learning.