Cow pregnancy guide
How long is a cow pregnant?
A cow is pregnant for about 283 days (about 9.3 months). The normal range is 274 to 292 days, so most calf arrive within that window rather than on the exact average day. Breed shifts the date by a few days, which is why the calculator asks for it.
Quick rule: Count about 9.5 months forward from the breeding or ai date, then adjust for breed.
How to use the cow pregnancy calculator
1. Enter the breeding or ai date. The day of artificial insemination or natural service. Tap Use today if it was today.
2. Pick the breed. The whole window moves with the breed average.
Then follow the schedule. Each task gets a real date, the next one is highlighted, the status shows whether your cow is on track, and the month by month cards above show where things stand. Use Copy schedule or Add to Google Calendar to keep it.
Gestation formulas
- Estimated calving date = breeding or ai date + 283 days
- Earliest normal calving = breeding or ai date + 274 days
- Latest normal calving = breeding or ai date + 292 days
- Breed adjustment = breed average minus 283 days, applied to the whole window
- Call your vet if nothing has happened by day 297
Care schedule for a pregnant cow
| When | Task | Why |
|---|---|---|
| Day 21 | Watch for return to heat | No heat around days 18 to 24 suggests she is pregnant. |
| Day 35 | Pregnancy check | Ultrasound from about day 30, or palpation by your vet from day 35 to 45. |
| 60 days before due date | Dry off for dairy cows | About 60 days of rest before calving. |
| 42 days before due date | Scours vaccine booster | Rotavirus, coronavirus and E. coli vaccine about 3 to 6 weeks before calving. Check the label. |
| 14 days before due date | Move to calving area | Clean, dry pen or paddock you can watch easily. |
Signs of calving and when to call the vet
Labour is close if she has
- ✓Udder full and teats waxed or leaking
- ✓Pelvic ligaments relax and the tailhead looks raised
- ✓Restless, isolating herself, tail held out
- ✓Water bag or feet visible
Call your vet immediately if
- !Strong straining for 30 minutes with no calf born
- !A baby is visible but stuck, or comes backwards with no progress
- !Heavy bleeding or foul-smelling discharge
- !She is weak, collapsed, off her food or in obvious pain
- !No calving by day 297
Cow gestation by breed
| Breed or type | Average | Normal window from the start date |
|---|---|---|
| Standard or mixed breed | 283 days | 274 to 292 days |
| Holstein Friesian | 279 days | 270 to 288 days |
| Jersey | 279 days | 270 to 288 days |
| Angus | 281 days | 272 to 290 days |
| Hereford | 285 days | 276 to 294 days |
| Brown Swiss | 290 days | 281 to 299 days |
| Simmental | 288 days | 279 to 297 days |
| Charolais or Limousin | 289 days | 280 to 298 days |
| Sahiwal or Red Sindhi | 285 days | 276 to 294 days |
| Brahman | 292 days | 283 to 301 days |
Frequently asked questions
How long is a cow pregnant?
A cow is pregnant for about 283 days (about 9.3 months). Most calf arrive between day 274 and day 292. Breed matters: Standard or mixed breed about 283 days, Holstein Friesian about 279 days, Jersey about 279 days, Angus about 281 days.
How accurate is this calculator?
It uses the average length and the normal range published in veterinary references, adjusted for the breed you pick. Individual animals vary, so treat the date as the middle of a window, not a promise.
When can I confirm the pregnancy?
Pregnancy check around day 35. Ultrasound from about day 30, or palpation by your vet from day 35 to 45.
What if she goes past the due date?
Going a few days past the average is normal. The calculator marks day 292 as the end of the usual window and day 297 as the point to call your vet even if she seems well.
What are the signs that calving is close?
Udder full and teats waxed or leaking. Pelvic ligaments relax and the tailhead looks raised. Restless, isolating herself, tail held out.
Is my data saved?
No. Everything is calculated in your browser. Nothing you type is stored or sent anywhere.
Disclaimer: This calculator gives estimates for planning only. It is not veterinary advice and cannot replace an examination by your vet. If you are worried at any stage, especially around birth, contact your vet promptly.
