It manifests itself as a rise in returns to service, abortions and delayed onset of oestrus.

It is thought to be primarily associated with rapidly-declining day-length. Affecting younger sows to a greater extent than mature animals, the levels of infertility are usually greater following a summer of low light levels. In view of the weather conditions this year, problems this autumn can be anticipated, warns JSR Genetics' consultant veterinary surgeon, Mark White.

Provision of extended lighting can go a long way to offsetting the problem. Between 14 and 16 hours of light - of sufficient intensity to allow close newsprint to be read at pig level - should be available for both weaned and served sows from August onwards, advises the company.

Source: JSR Genetics - 8th October 2004