Average pregnancy lengths
| Animal | Average | Normal range | Heat cycle |
|---|---|---|---|
| Cow | 283 days | 279–290 | 21 days |
| Buffalo | 310 days | 300–320 | 21 days |
| Goat | 150 days | 145–155 | 21 days |
| Sheep | 147 days | 144–152 | 17 days |
| Pig | 114 days | 112–116 | 21 days |
Breed, the age of the mother, twins and the sex of the calf all shift the date by a few days. Exotic and crossbred cows tend to be a little shorter than indigenous breeds.
Key dates for dairy animals
- Repeat heat check: around 18–24 days after AI. If she comes into heat again, she is probably not pregnant.
- Pregnancy diagnosis: by a vet from about 60–90 days after AI (earlier with ultrasound).
- Drying off: stop milking about 60 days before the expected date so the udder can rest and the calf grows well.
- Shift to a clean calving area about 2 weeks before the date and watch for signs: swollen udder, relaxed ligaments near the tail, restlessness.
Questions people ask
What if she hasn’t calved by the due date?
Up to about a week late can be normal. If she is well past the range or shows distress, call a vet.
Can I use this for natural mating?
Yes — use the date of the last observed mating.
When should a cow be inseminated after calving?
Usually from about 60 days after calving, at the first good heat, to aim for one calf a year. Your vet or AI technician can advise.
Sources
Results are estimates to help you plan. Always confirm important numbers with the seller, carrier or authority concerned. Last reviewed: November 2026.