• Ovulation occurs over a 6-8 hr period with a high fertilization rate
• 95-100% of the ova ovulated are fertilized
• Compared to cow and mare who have fertilization rate between 60-85%

Estrual Behavior

• Female will seek out boar
• may attempt to mount boar or other female
• will stand for mounting
• swollen and reddened vulva
• induction of mating posture by applying back pressure

• High mortality rate despite high rate of fertilization
• 35% of embryos resulting from fertilization die during pregnancy
• Majority of embryonic death occurs by day 25 of pregnancy

40% of sows will experience an estrus 2-3 days after parturition

Anovulatory- hence, not a fertile estrus

• Sows experience a true lactational anestrus where no estrous cycles occur while the piglets are nursing
• removal of the piglets will cause a fertile estrus within 3-7 days of weaning