Swine Gestation Calculator
The old farmer's rule for pig gestation is '3 months, 3 weeks, and 3 days,' which works out to about 114 days. Enter the breeding date and breed to calculate the expected farrowing date and prepare your farrowing facilities on time.
Swine gestation is remarkably consistent across breeds, averaging 114 days (about 3 months and 24 days). The variation between breeds is only 2-3 days, making farrowing one of the more predictable events on a livestock operation.
Breed-specific averages:
- Yorkshire/Large White: 113 days
- Chester White: 113 days
- Duroc: 114 days
- Hampshire: 114 days
- Berkshire: 115 days
- Landrace: 115 days
- Meishan: 116 days
Factors that affect farrowing date:
- Litter size: Sows carrying larger litters tend to farrow 1-2 days earlier
- Parity: First-litter gilts may farrow a day earlier than experienced sows
- Season: Some research shows slightly shorter gestations in summer
- Induction: Many commercial operations induce farrowing with prostaglandin (Lutalyse) on day 113 to synchronize births for management purposes
Preparing the farrowing area:
Move the sow to a clean, disinfected farrowing crate or pen about 5-7 days before the expected date. The area should be warm (heat lamps set at 90-95F for piglets), dry, and draft-free. Have towels, iodine for navel dipping, and a source of supplemental colostrum on hand. Most sows farrow without assistance, but monitoring the first few hours is important to make sure all piglets find the teats and start nursing.
Sows typically deliver their entire litter over 2-5 hours, with 15-20 minutes between piglets. If more than 45 minutes pass between piglets, intervention may be needed.