Swine Gestation Calculator – Guide & Formulas
Calculate your sow's farrowing date instantly. Enter the breeding date to find the expected due date, current gestation day, and development stage for your pregnant pig.
Calculate your sow's farrowing date with our free swine gestation calculator. Enter the breeding date to find the expected due date and current gestation stage.
Key Takeaway
Use the free Swine Gestation Calculator to calculate your sow's farrowing date instantly. enter the breeding date to find the expected due date, current gestation day, and development stage for your pregnant pig. Get instant results with step-by-step explanations.
How to Use the Swine Gestation Calculator
- Enter the date your sow was bred or artificially inseminated.
- The calculator computes the expected farrowing date based on 114-day swine gestation.
- Review the current gestation day and days remaining until farrowing.
- Check the developmental stage to understand fetal growth milestones.
- Plan farrowing preparations and nursery management based on the timeline.
The Formula
Variable Definitions
- Gestation: The period from conception to birth, averaging 114 days in pigs
- Farrowing: The process of giving birth in pigs
- Sow: An adult female pig (farrowed at least once)
- Boar: An intact male pig
- Gilt: A young female pig that has not yet farrowed
- Piglet: A baby pig
Calculating Sow Farrowing Date from March Breeding
Find the farrowing date for a sow bred on March 10, 2026.
- Step 1: Identify the breeding date: March 10, 2026.
- Step 2: Add 114 days gestation period to the breeding date.
- Step 3: Days remaining in March: 31 - 10 = 21 days. 114 - 21 = 93 days remaining.
- Step 4: Apr(30) + May(31) + Jun(30) = 91 days. 93 - 91 = 2 days.
- Step 5: The estimated farrowing date is July 2, 2026.
Financial Advisory Notice
This Swine Gestation Calculator provides estimates based on average porcine gestation periods. Individual pregnancies may vary based on breed, nutrition, and health status. Always consult a swine veterinarian for breeding management and farrowing assistance.
Frequently Asked Questions
How long is a pig pregnant in days?
A pig is pregnant for approximately 114 days (about 3 months, 3 weeks, and 3 days — often remembered as "3-3-3"). The normal range is 110 to 120 days. Breed can influence gestation — large breeds like Large White average 114-116 days, while some miniature breeds go 112-114 days.
How can I tell if my sow is pregnant?
Signs include: return to normal behavior after breeding, weight gain, increased appetite, and relaxed abdomen. The most reliable method is ultrasound at day 21-28. Sows that do not return to heat 18-24 days after breeding are likely pregnant.
How many piglets does a sow usually have?
Average litter size is 10-14 piglets, but this varies by breed and parity (number of litters). First-time gilts typically have 8-10 piglets. Mature sows can have 12-16. Some breeds like Landrace average 14-16 piglets per litter.
When should I move the sow to the farrowing crate?
Move the sow to the farrowing area 3-7 days before her expected farrowing date. This allows her to adapt to the new environment and reduces stress. Ensure the farrowing crate is clean, dry, and equipped with heat lamps for piglets.
What are signs of approaching farrowing in pigs?
Signs include: restlessness, nesting behavior (gathering straw), loss of appetite, vulva swelling and reddening, and milk dripping from teats. Active farrowing begins with water bag appearance and strong contractions.
How long does pig farrowing take?
Stage 1 (early labor): 2-8 hours of restlessness. Stage 2 (active delivery): 1-6 hours from first piglet to last, with intervals of 10-20 minutes between piglets. Stage 3 (placenta): 1-3 hours. If no progress after 30 minutes, or if more than 2 hours pass between piglets, call your vet.
Should I assist with farrowing?
Most sows farrow without assistance. Assist if: no progress after 30 minutes of active pushing, only one leg or head visible (malpresentation), excessive bleeding, or the sow appears severely distressed. Keep the environment quiet and minimize interference.
How long after farrowing can a sow be rebred?
Sows can be rebred as early as 3-7 days after farrowing (early weaning system) or at weaning (21-28 days). The industry standard is to rebreed at weaning. Allow the sow to recover for at least 24 hours after farrowing before rebreeding.