Enter the mating date to work out when your mare is due. Horses are pregnant for about 340 days.
Horses are pregnant for about 340 days, and most give birth between day 320 and day 360 after mating. Enter the mating date for a due date and a timeline.
Use the date of the last covering. Mares often carry longer than the average, so the range is wide.
| Typical length | 340 days from mating |
|---|---|
| Usual range | Day 320 to day 360 |
| Day 14 | Your vet will usually scan around now to confirm pregnancy and check for twins. |
| Day 150 | Ask your vet about equine herpesvirus vaccination, often given in the fifth, seventh and ninth months. |
| Day 310 | Ask your vet about a tetanus and flu booster before foaling, and watch for waxing up of her teats. |
How to use it
Choose the animal and enter the date she was mated. The calculator adds the typical length of pregnancy for that species to give a due date, and shows the window in which most births happen. It also lists the checks and preparations worth planning, with their dates.
Pregnancy length varies between individuals, breeds and litter sizes, and counting from mating rather than ovulation adds a few days either way. Treat the due date as a guide and keep watching her closely as the window approaches.
Call your vet if she goes past the end of the normal window, strains for a long time without producing young, seems weak or distressed, has a green or bloody discharge before any young arrive, or if a long gap passes between births.
About 340 days, around 11 months, from mating. Most horses give birth between day 320 and day 360.
From about day 14 after mating. Your vet will usually scan around now to confirm pregnancy and check for twins.
If she goes past day 360 without giving birth, or shows signs of distress, straining without result or an unusual discharge at any point, contact your vet.
Use the first mating for dogs and cats, as eggs can be fertilised over several days. Use the last covering for mares. For livestock, use the service date, or the raddle mark for sheep.
It is a guide. Most births fall within the window shown, and ultrasound scans can narrow it down. Large litters often arrive a little early and single young a little late.
These tools are planning aids, not a diagnosis or a replacement for veterinary advice. If a pet is unwell, has eaten something risky, or you are unsure what to do next, contact a vet.