Despite the unusually wet weather we have seen this year it is still possible that we may see some ‘summer’ or ‘seasonal’ infertility. This principally manifests itself as an increase in the number of sows returning to service and increased numbers of sows found not-in-pig. The knock-on effect of this is a reduced farrowing rate in the autumn and early winter; with the associated loss in production the financial losses can be high.

The increase in temperature associated with hot summers can be offset in outdoor herds by relatively simple means. Providing shade, wallows and ensuring a plentiful and clean water supply is essential. Painting the outside of huts and arcs white will help reduce the amount of heat absorbed by these structures, as will insulation. It may be worth moving stock in the early morning or evening to avoid the heat of the day; feeding at this time can also see increased intakes and less feed wastage.

Poor ventilation in farrowing huts or arcs may mean sows choose to lie outside, reducing piglet milk intake and therefore growth. To reduce piglet losses the farrowing huts should be as well ventilated as possible along with the judicious use of fenders to retain the piglets.

If seasonal infertility has been a problem in the herd in the past some planning is necessary to ensure that there are extra gilts to serve in the risk period from June to September to boost farrowing numbers and prevent the dip in production later on. Boars can also be affected by hot weather, older boars in particular may be disinclined to work, and so strategic use of AI can help, as can planning boar intake so there are younger, keener boars on farm.

There are many different components to this complicated syndrome, each farm will have its own challenges and situations, but with careful planning much can be done to limit the physical and financial losses associated with it.

Summer Infertility Series