Parturition Behaviour - Sow

Most farrowing takes place at night. The foetal membranes of adjacent piglets are usually fused and because individual or aggregated afterbirths may be expelled during the phase of foetal expulsion as well as after the birth of the last foetus there are no real separate stages of labour.

• Sows in late pregnancy usually sleep in lateral recumbency in the 24 hours before birth of the first piglet.
• Restlessness
• Bed making activity
• Intensely active period followed by recumbency and rest.
• Following this period of rest, clawing of the bedding resumes.
• Several alternating periods of rest and bed-making.
• In the hour preceeding the birth of the first piglet, the sow settles into lateral recumbency.
• Mammary growth occurs in late gestation.
  • 1-2 days before farrowing the individual glands are clearly demarcated, turgid, tense and warm.
  • Milk can be expressed during the final 24 hours.
• Progressive swelling of the vulval labia from ~4 days before parturition.
• Vulval mucosal becomes reddened
• Sows usually remain in lateral recumbency, but guilts get up after the first or second piglet and change from one side to the other, or from lateral to ventral recumbency.
• Straining and paddling leg movements.

• Births are heralded by passing of a small quantity of foetal fluid and marked by tail twitching.
• Expulsion of the first piglet requires the most effort.
• Allantochorion and amnion usually rupture as the conceptus traverses the birth canal.
  • Occasionally piglets are born within the amnion.
  • Foetus may be surrounded by membranes of another foetus.
• Offspring delivered randomy from both uterine horns.
• Average duration of the expulsive stage is 2-3 hours.
• Mean interval between successive births is 16 minutes.
• Umbillical cords may be intact or ruptured.
• Piglets are active and attempt to suckle within a few minutes.

• Foetal membranes are usually expelled as 2/3 masses of joined allontochorions with placental stalks of the umbillical cords indicating the number of conceptuses in each mass.
• Single afterbirths may also be voided.
• One or more masses are usually passes before all the piglets are born.
• Largest mass is usually passed ~4 hours after the birth of the last piglet.

• When all piglets have been expelled, the sow usually stands up and micturates.
• Then lies down again
  • Risk of crushing the piglets!
• Sow remains down for a period of time and allows the piglets to suckle.