Autumn infertility can cause severe economic loss, but it is often disregarded because the impact is not usually picked up until a year later, when producers find they have fewer pigs in the finishing pens.

Actions to avoid autumn infertility need to start now. Leaving it later could mean fewer finished pigs next spring.

During the autumn period sows naturally find it more difficult to conceive – in the wild state they don’t want to farrow in mid-winter when resources are in short supply, says Malcolm Stead, Production Director at ACMC.

“Day length falls rapidly at the end of June and the shorter days in July and August are one of the triggers for breeding sows to show an increased number in returns to service.”

To reduce the problem, he advises that where possible, sows and gilts are subject to a 16-hour of light/eight-hour of dark cycle day, using a light source of at least 200 lux in dry-sow/gilt houses.

Indoors it is important to check that all fluorescent tubes are working properly and to consider replacements with higher-intensity tubes. Light levels are difficult to judge by eye, but can be measured by using a light meter.

Outdoor producers need to follow a different tack, but they must be aware of rising temperatures. Following a spell of hot weather, sows may fail to conceive and often reabsorb their embryos or abort. This can result in a 10-35 per cent drop in the breeding rate.

Hot weather will also damage sperm production in boars — it only takes a few days, but the effects can last up to six weeks. “That’s why it’s a good idea to use AI cover during the summer and autumn, since semen will have been quality-checked before dispatch — something that can’t easily be guaranteed with natural service!” says Malcolm.

The best insurance against a dip in production is to serve more gilts — ACMC recommends around 15 per cent more.

Gilts brought in now can be served after an acclimatisation/isolation period which means their progeny will be ready for slaughter next spring, just in time to catch the price recovery after the New Year low!