Lambing & calving due-date calculator
Enter the mating (or breeding / service / cover) date and pick the species — we'll compute the expected birth date based on the average gestation, plus the realistic earlier/later window.
How long is the gestation period for each species?
Gestation length is remarkably consistent within a species but varies by breed, parity (first-time vs experienced mother), and whether she's carrying a singleton or multiples. The numbers below are the standard veterinary averages used to compute the date above.
| Species | Average gestation | Typical range |
|---|---|---|
| 🐑 Sheep (ewe) | 147 days | 144–152 days |
| 🐐 Goat (doe) | 150 days | 145–155 days |
| 🐄 Cattle (cow) | 283 days | 277–290 days |
| 🐖 Pig (sow) | 114 days | 112–116 days |
| 🐴 Horse (mare) | 340 days | 320–360 days |
| 🐇 Rabbit (doe) | 31 days | 28–33 days |
| 🦙 Llama | 350 days | 335–365 days |
| 🦙 Alpaca | 345 days | 335–355 days |
What if she's overdue?
A few days past the average is normal — but more than a week past the upper end of the range, especially if she's restless, off feed, or showing labor signs without progress, warrants a vet check. A stuck birth (dystocia) is fatal in under an hour for most species.
Avoid forgetting again — record breedings in Farm Planner
Track every mating, get an automatic due-date countdown on your morning briefing, and record births in two taps. 30-day free trial — no charge during the trial, cancel any time.
Sources: Merck Veterinary Manual, USDA livestock production handbooks, breed association reference data. Always consult your veterinarian for case-specific advice — this calculator is a planning tool, not medical advice.