Colonic events (volumina, fermentability, rate of passage) were determined in a complex program with young sows using 8 rations. Ileal cannulated sows were used and 4 slaughtered animals per ration to study volumina contents and to take samples for in vitro fermentation. The results are compared with 81 former experiments using ileal cannulated sows. Ileal nutrient flow was very different in quality and quantity. It varied between 1674 and 520 g OM/d, affecting seriously postileal reactions. Volumina of large intestine varied between 10 and 25 litres or between 83 and 226 ml/kg LW being determined by ileal flow rate (B = 0.90). The flow rate influenced also transit time (B = 0.89). Fermentability of OM in average come to 60% (from 33 to 77%) according to ileal flow composition.