Calculate pig farrowing dates by breed with 112-120 day gestation periods, farrowing crate timing, neonatal care milestones, and weaning schedules.
Swine gestation averages 114 days — commonly remembered as "3 months, 3 weeks, and 3 days." The actual range is 112-120 days depending on breed, litter size, and whether the sow is a first-timer (gilt). Large meat breeds (Yorkshire, Landrace) average 114 days, while heritage breeds (Berkshire, Tamworth) may run 115-117 days, and miniature breeds (Juliana, KuneKune) 113-116 days.
Unlike sheep and cattle, sows are non-seasonal breeders and can be bred year-round. Commercial operations target 2.3-2.5 litters per year with 21-28 day weaning. The interval from weaning to estrus is typically 3-7 days. Litter size varies enormously by breed: commercial hybrids average 12-16 piglets born alive, heritage breeds 6-10, and miniature breeds 4-8.
Pre-farrowing preparation is critical for piglet survival — the first 72 hours are the highest-mortality period due to crushing, hypothermia, and starvation. Farrowing crates or well-designed farrowing pens with creep areas and supplemental heat reduce neonatal mortality from 20-30% to 5-10%. This calculator tracks all critical dates from confirmed breeding through weaning.
Accurate farrowing date prediction ensures timely crate setup, supplemental heat preparation, iron injection scheduling, and creep feeding — all critical for reducing the 15-25% neonatal mortality rate. This swine gestation calculator helps you compare outcomes quickly and reduce avoidable mistakes when making day-to-day care decisions. Use the estimate as a planning baseline and confirm final decisions with a qualified professional when risk is high.
Gestation: "3 months, 3 weeks, 3 days" = 114 days average. Commercial breeds: 112-116 (avg 114). Heritage breeds: 114-118 (avg 116). Miniature pigs: 113-116 (avg 114). Gilts: may be +1-2 days. Move to farrowing: 5-7 days pre-due. Creep feed: start at 7-10 days. Processing (castration, iron, teeth): day 1-3.
Result: Farrowing: ~September 23, 2025. Move to farrowing crate: Sept 17. Creep feed: Oct 1. Wean: Oct 14.
A commercial sow bred June 1 with 114-day average gestation is due around September 23. She should be moved to the farrowing area 5-7 days early to acclimate. Piglets get iron injections on day 1-3 and start creep feed at day 7-10. Weaning at 21 days puts rebreeding around October 17-21.
**Hour 0-6:** Ensure every piglet nurses colostrum — they must receive antibodies within the first 6 hours. Dry off piglets born wet to prevent hypothermia. Clip needle teeth if fighting at the udder causes teat damage. Weight each piglet. **Day 1-3:** Iron dextran injection (200 mg IM). Dock tails if needed. Castrate male piglets if intended for market. Identify runts for supplemental feeding. **Day 3-7:** Ensure creep area at 85-90°F. Monitor sow for MMA (fever, off-feed, swollen mammary glands). **Day 7-14:** Begin creep feed. Piglets begin exploring beyond the creep area. Growth should be 0.5-1 lb/day.
Target: 2.4 litters/year per sow. **Gestation:** 114 days. **Lactation (weaning age):** 21-28 days. **Wean-to-breed interval:** 5-7 days. **Total cycle:** 140-149 days. **Annual capacity:** 365 / cycle = 2.4-2.6 litters. With 21-day weaning: 365 / 140 = 2.6 litters/year (commercial target). With 28-day weaning: 365 / 149 = 2.4 litters/year. With 42-day weaning (heritage/welfare): 365 / 163 = 2.2 litters/year.
**Commercial hybrids (Yorkshire × Landrace × Duroc):** 12-16 born alive, fast growth, lean carcass, require farrowing crates, 114-day gestation. **Heritage breeds (Berkshire, Tamworth, Gloucestershire Old Spots):** 6-10 born alive, slower growth, more marbling, can farrow outdoors, 115-118 day gestation, stronger maternal instincts. **Miniature pigs (KuneKune, Juliana, American Mini):** 4-8 piglets, 113-116 day gestation, can farrow indoors, popular for small farms.
Average 114 days or "3 months, 3 weeks, and 3 days." Range is 112-120 days. Larger litters tend toward shorter gestation (each piglet is smaller). Small litters (1-4 piglets) may run 116-120 days.
A gilt is a female pig that hasn't farrowed yet (first pregnancy). A sow has farrowed at least once. Gilts typically have smaller litters (2-4 fewer piglets), longer gestation (1-2 days), and may need more farrowing assistance. First gilts should be bred at 7-8 months of age and 280+ lbs.
Move her 5-7 days before the expected farrowing date. This allows her to acclimate to the new environment, reduces stress, and gives you time to ensure supplemental heat and the creep area are ready. Sudden moves close to farrowing can delay or complicate the process.
Signs include: restlessness and nest-building behavior, vulvar swelling and reddening, milk can be expressed from teats (within 24 hours), and a pink mucus discharge. Body temperature drops about 1°F 12-24 hours pre-farrowing.
Piglets are born with almost no body fat and very little hair. They need an ambient temperature of 85-95°F (30-35°C) in the creep area for the first week, decreasing by 5°F per week. Without supplemental heat, hypothermia sets in quickly and is the #1 cause of neonatal death along with crushing.
Sows typically return to estrus 3-7 days after weaning. Breeding on the first post-weaning heat usually produces the best conception rates and largest litters. This allows a 140-150 day cycle from farrowing to next farrowing, achieving 2.3-2.5 litters per year.