There is a considerable current interest in the feeding of high fibre diets to pregnant sows, with a view to gaining both economic and welfare advantages. The potential use of these diets will depend on the extent to which the fibrous materials are fermened in the hindgut, and the subsequent capacity of the products of the fermentation, that is VFAs, to meet the energy needs of the animal. Sugar beet pulp and wheat straw are two ingredients that have considerable potential as feed ingredients for sows. The present experiment was designed to study the extent to which diets containing high level of non-starch polysaccharides (NSP), largely from plain sugar beet pulp (SBP) or wheat straw (WS), influenced nutrient partition and the efficiency of ntrient utilisation in pregnant sows.