After weaning, sow has lost condition and has a negative energy balance. It should be fed on feed rich in energy and low in protein. This practice is known as flushing.
High levels of sugar and starch cause the secretion of digestive fluids, enzymes and hormones such as insulin. An insulin peak stimulates the production of fertility hormones so the sow quickly gets on heat between 3- 14 days after weaning, releases large number of eggs thus large litter size. I assume that you all know that nursing mothers don’t come on heat!
Feeding mother with too much protein after weaning until service (natural or Artificial insemination) has negative effect on both fertility and litter size. This is because the degraded protein causes ammonia toxicity in the body system and organs of a pig. The greatest need is energy got from starch and sugar.
The dry sow should be given 3 kg of sow and weaner feed per day.
Ensure fresh water 24(7), through nipples or water troughs available all the time (always fresh water and not a swimming pool!).
Research has proved that adding extra sugar (dextrose 200 g/sow/day) improves fertility and litter size in dry sows, this should be done until service date.