Best Time for Inseminating a Sow

Best time for inseminating a sow is:

Correct Answer: 2nd day of heat

In sows, the estrous cycle is 21 days and heat lasts 2–2.5 days. The best time for artificial insemination is the 2nd day of heat, as ovulation occurs around 35–45 hours after the onset of estrus, which aligns with the 2nd day.

Insemination Timing Across Species

• Cow: Mid-heat (standing heat) or 12–18 h after onset
• Sow: 2nd day of heat
• Mare: Every 2nd day during estrus
• Sheep (Ewe): 12–24 hours after onset of heat

Practical Tip

In sows, using the riding/back pressure test helps detect standing heat. The sow stands rigidly when back pressure is applied — this is the hallmark of true estrus in pigs.