Dietary fibre for pregnant sows: effect on performance and behaviour

The effect of high fibre levels in diets for pregnant sows was studied in a long-term experiment. Three diets were compared: A control (C) based on mainly barley and soya bean meal containing 176 g dietary fibre (DF, kg(-1)), a second with 500 g sugar beet pulp (SBP, kg(-1)) containing 446 g DF kg(-1) and a third with 500 g mixed fibre sources (MFS, as dried grass meal, wheat bran and oat hulls, kg(-1)) containing 344 g DF kg(-1). Compared with C, the SEP diet and the MFS diet had relatively high contents of soluble dietary fibre (SDF) and insoluble dietary fibre (IDF), respectively. NE content of the diets was 9.2, 8.7 and 7.0 MJ kg(-1) DM for C, SEP and MFS, respectively. The diets were used in a production trial combined with a behavioural study on sows. The first comprised 120 sows allocated to the three different pregnancy diets for three consecutive reproduction cycles, and the latter included 54 sows representing only one gestation period each. Irrespective of the diet, pregnant sows were fed similar levels of estimated daily net energy (NE). During lactation all sows were fed a standard diet semi-ad libitum. Because of reduced appetite of some sows, the mean intake of NE during gestation was significantly lower for SEP than for sows on C and MFS. On the other hand, sows in the SEP group had significantly higher lactational feed intake. Weight gain of sows during pregnancy and their weight loss at farrowing were significantly higher for SEP and MFS than for C. Litter size at birth and at weaning was not affected by diets, but weight of piglets at birth was negatively influenced by the high level of SEP. Weaning weight of piglets was not significantly different. Eating time for sows was significantly increased and the time spent on foraging was reduced for sows fed SEP and MFS. Aggression in sows was particularly reduced by the SEP diet. (C) 2001 Elsevier Science B.V. All rights reserved.