Reproduction performances and conditions of group-housed non ...

- Paper I -
the first four weeks after mating could perhaps impair pregnancy rate in gilts and litter size
in sows fed restricted during lactation.
As regards before mating, it is not possible to say how huge impact the involvement in aggressive
interactions has on a sow’s appetite and therefore whether variation in feed intake
can influence the variation in litter size and pregnancy rate. Further studies are needed to
clarify this.
6. Conclusion
Based upon a review of existing literature, it is suggested that pregnancy rate and litter size
can be influenced by energy intake although the results reviewed do not provide a clear
picture. There is little doubt, however, that the reproduction performance of the gilt, in general,
is more influenced by energy supply than the reproduction performance of the sow. It
is further suggested that variation in feed intake in a group of restricted fed pregnant female
pigs in commercial pig husbandry, may be large enough to influence pregnancy rate and
litter size. However, there is no empiricism to support this, why there is a need for studies
analyzing whether a relation between individual feed intake and reproduction performance
exists in a group of non-lactating female pigs.
41