The profitability of pig farming is determined to a large extent by the reproductive performance that’s number of piglets born alive/sow/year. This is governed by two factors; litter size and number of litters each produces each year.
Gestation length =114 days.
Lactation length = 28 days.
Weaning to oestrus = 8days.
Total = 150 days.
Potential = 2.4 litters/sow/year.
Average piglets born alive per litter 14. Therefore, number of piglets / sow / years = 28.
Infectious diseases can play a role in reproductive failure but there is a tendency to blame them for everything. Many microorganisms cause reproductive failure in pigs. However, it is frequently hard to prove they are involved with the reproductive failure.
Reproductive failure occurs when the bred sow or gilt does not conceive or fails to farrow a healthy litter. It may appear as: normal return to oestrus (18-24 days), delayed return to oestrus (<25 days), abortion, pseudo pregnancy, failure to farrow, mummified foetuses, still births, small litter size, abnormal/malformed piglets and decreased neonatal survival.