Foal Calculator

Foaling Calculator

Here are some quick facts: Most mares cycle every 21 days. The egg is viable for 24 hours and semen is viable for 48 hours. If there is a low sperm count, it is a good idea to breed daily. Allowing the mare and stallion to pasture breed gives you the best chance for a foal.

Gestation averages about 336 days. For a due date count back 25 days. If she was last bred on April 26, she's due on April 1. This could vary by 10 days early or late. Supposedly, research has shown that 70% of all mares may repeat their first pregnancy cycle regardless of whether it is a filly or colt. If you know the number of days of her gestation in previous pregnancies, you can check that number against this pregnancy to see how close she is to repeating her cycle each year. Our Turbolina has her babies 338 days after she was last bred. Keeping a record of each mare's pregnancies is thus helpful.

We narrow down our foaling dates by looking at all the signs of foaling and by using milk strips! Click here to learn about milk strips!

I have been told by a few different vets that mares due in the early part of the year or in colder climate, birth later than average, and that those mares due in the early spring or in warmer climates are more likely to birth on time or a bit earlier than average. Could this be because the foals born in colder climates and earlier in the year need to grow a longer coat of fuzz before they pop out?

Foal heat is normally 10 days post foaling. Again there is a lot of variance. Our favorite mare comes in 18 days post foaling.

Is your mare overdue? Click here for a great article that will give you some parameters.

Use these calculators to check your Mares Foaling Date:

To calculate your mare's approximate "due date"

Enter her last breeding date in format shown:

Next, enter duration of gestation in days:
(our favorite mare goes 338 days)

Your mare's estimated foaling date:

To calculate number of days your mare is "in foal"

Enter last date mare was bred in format shown:

Next, enter today's date in format shown:

Estimate of days mare has been in foal:

We did have a fun thread on our AZminiatures yahoo group wherein one breeder told of a mare that went 384 days and another mare who waited 372 days. Those have got to be record long for gestation times. On the short end, one miniature breeder told of a baby born at 296 days with only peach fuzz, no hair and cartilage for legs. The vet told this lady she would die, but love and determination (along with lots of hours) has grown this baby up to be 4 years old now. They had to be there every 2 hours around the clock and support her while she nursed. After 2 weeks, she was getting up on her own! As you can see, there can be a great amount of variation.

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