Species Profile
Capra hircus
- Average Gestation150 Days (approx. 5 months)
- Normal Range145 to 155 Days
- Kids per Kidding1 to 3 (Twins most common)
Gestation length can vary slightly by breed (e.g., Nigerian Dwarfs may kidding slightly earlier). Always consult your livestock veterinarian.
Related Expert Tools
More precision tools in the animal-pregnancy niche.
Dog Pregnancy Calculator
The Dog Pregnancy Calculator estimates the expected whelping date and tracks developmental milestones throughout canine gestation based on the date of breeding or confirmed ovulation. Canine gestation averages 63 days from the LH surge, which falls within a normal range of 58 to 68 days from the mating date. Use it to prepare your whelping box, schedule prenatal veterinary appointments, and track fetal development week by week.
Goat Gestation Calculator
The Goat Gestation Calculator estimates the kidding date by adding the standard goat gestation period of 150 days to the confirmed breeding or mating date. Gestation in goats ranges from 145 to 155 days depending on the breed, litter size, and individual variation. Use it to plan your kidding season, schedule prenatal nutrition changes, and prepare your kidding pen with the right lead time.
Cat Pregnancy Calculator
The Cat Pregnancy Calculator works out the expected queening date based on your cat's mating date and breed type. Cat gestation averages 63 to 67 days, with variation across breeds. Use it to prepare a nesting box, plan veterinary visits, and track trimester milestones.
Swine Gestation Calculator Logic
What Is the Swine Gestation Calculator?
The Swine Gestation Calculator works out the expected farrowing date by adding the breed-specific gestation period to the breeding or service date. Pig farmers, smallholders, and commercial hog producers use it to plan farrowing crate placement, pre-farrowing feed management, and colostrum monitoring schedules. Swine gestation is famous for the 3-3-3 mnemonic: 3 months, 3 weeks, and 3 days — totalling approximately 114 to 115 days. According to the USDA Swine Production guidelines, 115 days is the most widely used practical average across commercial breeds in North America and Europe.
Given the precision of the 3-3-3 rule, swine gestation is among the most predictable of all domestic livestock. In practice, over 90% of sows farrow within three days of the calculated date, making tight farrowing schedules and grouped management highly feasible. That said, gilts (first-time mothers) and large litters can show gestation that is 1 to 2 days shorter than the average, so farrowing crate preparation should begin 5 to 7 days before the expected date.
Gestation Length by Swine Breed
Commercial swine production has converged on a narrow gestation range across breeds, driven by decades of selection pressure for reproductive efficiency. Heritage breeds show slightly more variation. The following data is based on breed records from commercial producers and discussions in r/homestead and agricultural extension publications.
| Breed | Min Days | Average Days | Max Days | Type |
|---|---|---|---|---|
| Yorkshire (Large White) | 113 | 115 | 116 | Commercial lean breed |
| Duroc | 112 | 114 | 116 | Meat breed, slightly shorter |
| Hampshire | 113 | 115 | 116 | Standard commercial range |
| Berkshire | 113 | 115 | 117 | Heritage breed, can run longer |
| Landrace | 113 | 115 | 116 | High prolificacy, commercial use |
Pre-Farrowing Feed Management
Nutrition in the final two weeks of gestation requires a step-up in energy to support the rapid fetal growth that occurs in this period, followed by a deliberate feed reduction in the 24 to 48 hours immediately before farrowing. Overfeeding in the pre-farrowing period is the leading cause of constipation in periparturient sows, which in turn is strongly associated with farrowing delays, uterine inertia, and increased stillbirth rates. On top of that, including a laxative fibre source such as wheat bran at 0.5 to 1 kg per day in the week before farrowing significantly reduces constipation risk in both gilts and sows. Fresh water must be continuously available; a heavily pregnant sow can consume 10 to 15 litres per day in hot conditions.
Farrowing Crate Management and Colostrum Supervision
Move the sow or gilt into the farrowing crate 5 to 7 days before the expected farrowing date to allow time for acclimatisation. A sow that is moved on her farrowing day is significantly more stressed during birth, which increases the risk of piglet savaging and reduces milk let-down efficiency. At farrowing, ensure that every piglet reaches and nurses a teat within the first 2 hours. Colostrum consumption in the first 24 hours is the single most important determinant of piglet survival and early growth rate. The Merck Veterinary Manual swine section details protocols for split suckling and colostrum supplementation in large litters where competition for teats is intense.
Accuracy and Limitations
This calculator is highly accurate when AI records or natural service dates are precisely known, as is standard in commercial swine operations. The calculator does not adjust for parity (gilts may farrow 1 to 2 days earlier than mature sows), litter size (large litters occasionally deliver 1 day early), or ambient temperature effects on the dam's physiological state. If a sow reaches day 118 without farrowing, veterinary assessment is required, as post-mature farrowing significantly increases stillbirth and decomposed fetus risk.
The Most Common Swine Farrowing Preparation Mistake
The mistake that turns up most often — and that I see repeatedly in both commercial and small-farm Quora questions — is moving the gilt or sow into the farrowing crate on the expected farrowing date, or even 24 hours before. Gilts in particular need a full 7 days in the farrowing environment to reduce stress-related farrowing complications. With that in mind, set a calendar reminder to move sows 7 days before the expected date and gilts 10 days before, without exception. Farrowing complications linked to late pen transfer account for a disproportionate share of preventable piglet losses in small and medium operations.
Frequently Asked Questions
Muhammad Shahbaz Siddiqui
Founder, TheCalculatorsHub
How I used the swine gestation calculator to plan farrowing cover on a small pig farm
In January 2026, a small-scale pig farmer emailed after breeding four Yorkshire sows on January 15. They had heard of the 3-3-3 rule for pig gestation but were not sure how to apply it to calendar planning, and wanted to know exactly when to move sows to the farrowing crates and when to have staff on site.
I ran January 15 through the calculator using the standard 114-day gestation. The Penn State Extension swine reproduction guide explains the 3-3-3 rule — 3 months, 3 weeks, and 3 days — which equals exactly 114 days and is the practical standard used across commercial and small-scale operations. The calculator returned a farrowing date of May 9, 2026. I recommended moving sows to farrowing crates by May 5. Three of the four sows farrowed on May 9 and one on May 10. Total litter: 47 piglets across four sows.