This pig gestation chart gives expected farrowing dates for breeding dates throughout the year, calculated using the 114-day average pig gestation period. For exact date calculations including intermediate dates, use the pig gestation calculator — enter the exact breeding date and get the full farrowing timeline.
The normal farrowing window is days 111–120 from the breeding date. Use the dates in this chart as your target, then plan monitoring to cover the 3-day window before through 6-day window after.
Pig Gestation Chart — Breeding Date to Farrowing Date
| Breeding Date | Expected Farrowing Date (+114 days) |
|---|---|
| Jan 1 | Apr 25 |
| Jan 15 | May 9 |
| Feb 1 | May 26 |
| Feb 15 | Jun 9 |
| Mar 1 | Jun 23 |
| Mar 15 | Jul 7 |
| Apr 1 | Jul 24 |
| Apr 15 | Aug 7 |
| May 1 | Aug 23 |
| May 15 | Sep 6 |
| Jun 1 | Sep 23 |
| Jun 15 | Oct 7 |
| Jul 1 | Oct 23 |
| Jul 15 | Nov 6 |
| Aug 1 | Nov 23 |
| Aug 15 | Dec 7 |
| Sep 1 | Dec 24 |
| Sep 15 | Jan 7 |
| Oct 1 | Jan 23 |
| Oct 15 | Feb 6 |
| Nov 1 | Feb 23 |
| Nov 15 | Mar 9 |
| Dec 1 | Mar 25 |
| Dec 15 | Apr 8 |
All dates calculated at +114 days. Normal farrowing range is days 111–120. Year assumes non-leap year for simplicity; leap year February dates shift by 1 day.
How to Use This Chart
Find your breeding date in the left column. The right column gives the expected farrowing date at exactly 114 days. Build your farrowing monitoring window around 3 days before through 6 days after this date.
For example: a sow bred on March 1 has an expected farrowing date of June 23. Begin intensive monitoring on June 20 (day 111) and continue through June 29 (day 120). Move the sow to the farrowing pen by June 16–18 (5–7 days before).
The 3-3-3 Mental Shortcut
If you don't have this chart available, the classic swine mnemonic works as a quick field estimate: add 3 months, 3 weeks, and 3 days to the breeding date. The result is typically within 1 day of the 114-day calculation — useful at the field level when you need a quick estimate without a calculator or chart.
Example: bred January 1 → add 3 months (April 1) → add 3 weeks (April 22) → add 3 days = April 25. This matches the chart exactly. In months with 31 days, the mnemonic comes out to 115 days rather than 114. In February, it may be 112–113 days depending on which part of February the breeding occurred. Use the calculator for precision; use the mnemonic for speed.
Normal vs Abnormal Farrowing Timing
Most farrowing outside the 111–120 day range warrants attention:
- Before day 109: Premature — piglets are typically non-viable. This may indicate a disease event (PRRS, parvovirus), severe stress, mycotoxin exposure, or estrogen-mimicking toxin exposure. Investigate immediately.
- Days 109–110: Marginally premature — piglets may survive with intensive support but are at high risk. Check environmental and health conditions.
- Days 111–120: Normal range. Most healthy sows farrow in this window.
- After day 120: Post-term — rare in pigs. If a sow shows no signs of farrowing by day 118–119 and the calculated date is past, contact your veterinarian. Induction with prostaglandin (e.g., lutalyse/dinoprost) may be appropriate under veterinary guidance.
Farrowing Management Checklist
As the expected date approaches, confirm:
- Farrowing crate or pen is clean and disinfected
- Heat source (lamp or mat) is in place and functional — piglets need 95°F (35°C) at floor level in the creep area
- Sow has been moved to the farrowing pen 5–7 days in advance
- Colostrum management plan is in place for litters larger than 14 pigs
- Monitoring schedule covers the full 111–120 day window (every 2–4 hours for gilts)
- Farrowing supplies are on hand: clean towels, iodine for navel dipping, iron injection for piglets, identification supplies
Sources & References
- Penn State Extension — Swine reproduction and farrowing management
- Merck Veterinary Manual — Porcine reproduction
- University of Minnesota Extension — Swine gestation and farrowing