High-Fibre feeding in gestation - The Gestating and Lactating Sow - page 93

24-h cycle. Physical activity appears to be a reliable indicator of prolonged postprandial
satiety, but investigations are needed to ascertain whether the increased lying periods
reported in sows fed bulky fibrous diets represents a reduced level of feeding motivation
or abdominal discomfort induced by high gastric distension with increased water binding
capacity of the diet.

5.4.4 Aggressive behaviour

The feed restriction applied in group-housed sows generates a competitive situation
whereby the degree of aggressive behaviour is modulated by the feeder designs and
feeding practices (Meunier-Salaün et al. , 2001). Fibrous diets may reduce the expression
of aggressive behaviour, as illustrated by the reduced vulva biting in sows fed high-fibre
diets by a computerized feeding station (Van Putten and Van de Burgwal, 1990), or
floor-fed (Whittaker et al. , 1999). A reduced severity of aggression was also reported in
dynamic groups on the first day following the introduction of sows in pens equipped with
a computerized feeding station, when sows were fed a high-fibre diet ad libitum compared
with a conventional diet at restricted level (Whittaker et al. , 1999). The feeding practice
can also modulate the effect of dietary fibre on aggressive interactions, which potentially
contributes to enhance the level of competition. For instance, when comparing sows
simultaneously-fed using troughs with sows fed with an electronic self-feeder (ESF),
feeding rate was lower in sows fed fibrous diets, thereby promoting higher displacements
at the trough in simultaneously-fed sows and leading to more non-feeding visits in sows
at the ESF (Courboulay et al., 2001).

The impact of dietary fibres on aggressive behaviour may also depend on the fibre
source. Indeed, Danielsen and Vestergaard (2001) showed that in sows fed isoenergetic
diets with either sugar beet pulp (50%) or mixed fibre sources (20% oat hulls, 15%
wheat bran and 15% dried grass meal), only incorporation of sugar beet pulp reduced
the frequency of aggression.

In summary, fibrous diets may potentially reduce aggressive behaviour related to feed
competition, but this effect depends on the fibre source and feeding conditions, and may
be more important if no foraging substrate is provided.

5.5 Impact of dietary fibres on performance

Data on the effects of dietary fibres on performance during pregnancy and lactation are
numerous and often inconclusive, due to large differences between studies with respect
to the fibre sources used, their incorporation rate, the housing conditions (e.g. individual
stalls or group-housing, conventional or enriched environment, feeding strategy), or the
individual characteristics of the sows (e.g. parity, weight, breed), as illustrated in Table 5.3.

Body weight or backfat gain during pregnancy do not seem to be affected by dietary
supplementation with fibre when energy supply is similar, irrespective of the fibre sources
or the parity of sows (Cerneau et al. , 1997; Farmer et al. , 1996; Guillemet et al. , 2007b;