Gestation Calculator. Every due date.
Work out when any of your animals are due. Enter the service, AI or mating date, choose the animal, and the calculator gives the expected due date using average gestation lengths for cattle, sheep, goats, pigs and horses.
Expected due date:
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Cattle tracked
Track every service and due date automatically
Herdwatch records services, scans and due dates for your whole herd or flock, and sends reminders straight to your phone. Trusted by over 100,000 farmers.
- Services, scans and due dates recorded in one place
- Reminders straight to your phone as each date approaches
- Compliant records ready for inspection
Gestation lengths
Gestation length is the number of days from conception (service, mating or AI) to birth. It varies by species, by breed, by the sire and by the individual animal, so treat the result as a target date rather than a guarantee.
The averages used by the calculator are shown below. For breed-specific cattle dates, use the Calving Calculator, which lets you pick the breed. Calving Calculator , which lets you pick the breed.
| Animal | Average gestation (days) | Roughly | Notes |
|---|---|---|---|
| Cattle (cow) | 283 | 9 months 1 week | 279 to 294 by breed |
| Sheep (ewe) | 147 | 5 months | Range about 142 to 152 |
| Goat (doe) | 150 | 5 months | Range about 145 to 155 |
| Pig (sow) | 115 | 3 mth 3 wk 3 dy | Range about 112 to 120 |
| Horse (mare) | 340 | 11 months | Range about 320 to 370 |
Source: standard breed and veterinary gestation averages. Individual animals will deliver a few days either side of these averages.
Tips for planning around due dates
- Record every service or mating date as it happens. Accurate dates in mean accurate due dates out.
- Start watching animals closely from about a week before the expected date (longer for horses).
- Keep a note of breed and sire. In cattle, gestation can shift the date by up to two weeks.
- Have your kit and vet's number ready before the first animal is due.
One app for the whole farm.
Herdwatch tracks breeding, medicines, compliance and more for cattle and sheep. Request a quote and we will tailor it to your farm.
Frequently asked questions
On average about 283 days, roughly nine months and one week. Dairy breeds such as Holstein Friesian tend to be shorter (around 279 days) and some continental beef breeds longer (up to 294 days).
About 147 days, or roughly five months, with most ewes lambing between 142 and 152 days after mating.
About 115 days, often remembered as three months, three weeks and three days.
About 340 days, roughly eleven months, though the range is wide at around 320 to 370 days.
This tool works one animal at a time. The Herdwatch app tracks services and due dates for every animal automatically and reminds you as each date approaches.