Cow gestation calculator and calving calendar
A cow carries her calf for about 283 days — roughly nine months and ten days. This cow gestation calculator adds that to the date of artificial insemination (AI) or natural service and gives the expected calving date, together with the dates that matter on the way: when to watch for a return to heat, when to ask the vet for a pregnancy check, when to dry her off and start steaming up, and when her next heat is likely after calving.
The same calculator covers buffaloes (310 days), goats (150), sheep (147), pigs (114) and horses (340). Every length can be changed to match your breed or your own herd records. A gestation chart shows the due date for every species at once, and a month calendar lists the due date for every possible service date — handy to print and pin up in the shed.
How to use the cow gestation calculator
- Choose the animal. The gestation length fills in automatically; change it if your vet or breed society uses another figure.
- Enter the service or AI date. The expected calving date and today’s day of pregnancy appear at once.
- Read the schedule: return-to-heat window, pregnancy check, dry-off and steaming up, the move to a calving area and the next heat.
- To plan breeding, switch to Service date for a due date and enter when you want the animal to give birth.
- Open the month calendar to list due dates for a whole month of services, then download it as CSV or print it.
Cow Gestation Calculator features
Six species
Cow, buffalo, goat, sheep, pig and horse, each with an editable gestation length.
Full breeding schedule
Heat checks at one and two cycles, pregnancy check, dry-off, calving area and first heat afterwards.
Both directions
Due date from the service date, or the service date needed for a target calving date.
Progress today
Shows which day of pregnancy it is today and how many days are left.
Printable calendar
A month of service dates with heat check, dry-off and due date, as CSV or print.
Gestation periods of farm animals
Sources: Merck Veterinary Manual tables “Approximate Gestation Periods” and “Features of the Reproductive Cycle”; Oklahoma State University Extension’s 283-day cattle gestation table; IVIS Bubaline Theriogenology for buffalo. Breed matters: Holstein and Jersey cows average a few days less than 283, Brahman-type and Gir cattle a few days more, and swamp buffaloes carry 320–340 days.
| Animal | Average gestation | Heat cycle | Example: served 1 January 2026 |
|---|---|---|---|
| Cow | 283 days | 21 days (18–24) | 11 October 2026 |
| Buffalo | 310 days (river breeds 305–315) | about 21 days | 7 November 2026 |
| Goat | 150 days | 21 days | 31 May 2026 |
| Sheep | 147 days | 17 days (14–20) | 28 May 2026 |
| Pig | 114 days | 21 days (19–23) | 25 April 2026 |
| Horse | 340 days | about 21 days (19–23) | 7 December 2026 |
Worked example and dairy timeline
A crossbred cow inseminated on 1 January 2026: 283 days later is Sunday 11 October 2026. Watch for heat 19–25 January and again in February; if she stays quiet, have her checked by a vet from early March. Dry her off around 12 August, about 60 days before calving, so the udder can rest and the calf grows well, and add about 1 kg of concentrate a day in those last two months — the cattle feed calculator includes that allowance. Move her to a clean calving area by 4 October and expect her first heat 20–60 days after calving.
To count days between any two dates, the date difference calculator is quicker; for human pregnancy, use the pregnancy due date calculator.
Why a calf can come early or late
- Bull calves are usually carried a day or two longer than heifer calves; twins usually arrive early.
- Heifers calving for the first time often calve a little earlier than mature cows.
- Breed, season and nutrition all shift the length by several days, so plan for a week either side.
- Being well past the date, straining for more than an hour without progress, or a calf in the wrong position needs a veterinarian.
Cow Gestation Calculator FAQ
How long is a cow pregnant?
About 283 days on average, roughly 9 months and 10 days. Most cows calve within a week of the calculated date.
How do I calculate a cow’s due date?
Add 283 days to the date of AI or service. For a cow served on 1 January 2026, the expected calving date is 11 October 2026. The cow gestation calculator does it and lists the dry-off and heat-check dates too.
What is the gestation period of a buffalo?
About 310 days for river buffaloes such as Murrah (305–315 days); swamp buffaloes carry 320–340 days.
When should a cow be dried off?
About 60 days before the expected calving date. For a due date of 11 October, that is around 12 August.
How long are goats, sheep and pigs pregnant?
Goats about 150 days, sheep about 147, and pigs 114 days — three months, three weeks and three days.
Can I print a gestation calendar for my herd?
Yes. Open the month calendar, choose the month of service, and press Print or download the CSV for a spreadsheet.