About the Livestock Gestation Calculator
This livestock gestation calculator estimates when a cow, mare, doe goat, ewe, sow or rabbit doe is due from the date she was bred or inseminated. Choose the species, enter the breeding date and a check date, and it returns the estimated due date, the normal range of birth dates, how many days into the pregnancy she is, how far through it she is as a percentage, and a dated timeline with pregnancy check and preparation milestones.
It is built for small farmers, homesteaders, 4-H and FFA members and anyone planning a breeding calendar — for example to time calving for spring grass, keep goats from kidding in the coldest weeks, or have the farrowing pen ready on time. Enter the first service date if the animal was bred more than once.
The averages used are typical figures for common breeds: about 283 days for cattle, 340 for horses, 150 for goats, 147 for sheep, 114 for pigs (“three months, three weeks and three days”) and 31 for rabbits. Breed, sex of the offspring, litter size, season and the individual animal all shift the real date, so watch for signs of birth from the start of the range and ask your vet if an animal goes well past it.
How to use the livestock gestation calculator
- 1Choose the species.
- 2Enter the breeding or artificial insemination date (the first, if repeated).
- 3Enter today’s date to see how far along she is.
- 4Read the due date and normal birth window.
- 5Use the timeline to book a pregnancy check and prepare the birthing area.
Formula and method
The calculator adds the species’ average gestation length to the breeding date: cattle 283 days (normal range 279–292), horses 340 days (320–370), goats 150 days (145–155), sheep 147 days (142–152), pigs 114 days (111–117) and rabbits 31 days (28–35). The earliest and latest normal dates add the ends of the range instead.
Days since breeding is the gap between the breeding date and the check date; percentage complete is that figure divided by the average gestation. Pregnancy is split into thirds for the stage label, and the preparation milestone falls about two weeks before the due date for long pregnancies (one week for goats, sheep and pigs, three days for rabbits). These are typical figures — breed and individual differences are real, so treat the result as a planning estimate.
- Average gestation
- Typical pregnancy length for the species, in days
- Range
- Typical minimum and maximum gestation for healthy animals
Worked examples
Cow bred on 1 June 2026
Adding 283 days to 1 June 2026 gives a calving date of 11 March 2027, with normal calving from 7 to 20 March. On 15 October she is 136 days along, about 48% of the way through.
Mare bred on 15 April 2026
A mare bred on 15 April has an average foaling date of 21 March 2027 (340 days). On 1 March she reaches day 320, the start of the normal 320–370 day window, so the foaling stall should be ready.
Goat bred on 1 October 2026
At 150 days, a doe bred on 1 October should kid around 28 February 2027, normally between 23 February and 5 March. Two weeks after breeding she is on day 14 with 136 days to go.
Sow bred on 20 September 2026
Three months, three weeks and three days (114 days) after 20 September is 12 January 2027. On 15 October she is on day 25 — a good time for an ultrasound pregnancy check.
Frequently asked questions
How long is a cow pregnant?+
About 283 days, or a little over nine months, with most cows calving between about 279 and 292 days. Some breeds run longer, and bull calves are often carried a day or two longer than heifer calves.
How long is a horse pregnant?+
Mares carry foals for about 340 days (around 11 months), but anything from about 320 to 370 days can be normal. Foals conceived early in the year are often carried a little longer than those conceived later in the season.
How long are goats and sheep pregnant?+
Goats are pregnant for about 150 days (roughly 145–155) and sheep for about 147 days (roughly 142–152). Some smaller breeds kid or lamb a few days earlier.
How long is a pig pregnant?+
About 114 days, often remembered as three months, three weeks and three days. Most sows and gilts farrow between about 111 and 117 days after breeding.
How long is a rabbit pregnant?+
Rabbits are pregnant for about 31 days, with kits usually born between days 28 and 35. Give the doe a nest box a few days before kindling; if she has not kindled by about day 32–34, ask a vet for advice.