What you see. The starting point for addressing any equine health related issue is your observation.


Pregnancy, Mare is Overdue, Over 340 Days Pregnant


Mares commonly have gestation lengths longer than the average of 335-340 days, and this is a common concern to horse owners. Usually, there is no cause for worry. Gestation can be as long as 375 days and the record gestation length is over 400 days.

Of course, in the last weeks of pregnancy, a mare should show signs of advancing pregnancy. Her udder should be filling and her abdomen should be pendulous as she nears her due date.

  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • If you are concerned about the pregnancy or the mare and want an evaluation.
  • Code Green

    Contact Your Vet to Obtain Useful Advice & Resources
    • You have any concerns about the late-term pregnant mare.

your role


What To Do

When in doubt, assess the mare's general health using the Whole Horse Exam on Late-Term Mare (WHE), and contact your vet to discuss your findings and concerns. Watch and feel the mare's flanks for movement of the fetus.

Keep an eye on the color of secretion from the teats by squeezing a drop or two into your palm every few days. As a mare nears foaling, the secretion will turn from clear, honey looking liquid to looking like real milk. (If your mare is exhibiting none of these signs, keep in mind that she may no longer be pregnant.)

Be sure to record the breeding dates, reproductive history of the mare and stallion including a record of prior foals and the years they were born. Supply all that information to your vet.

What Not To Do

Just because the mare was pregnant in the early stages of pregnancy, do not simply assume that she still is pregnant.

your vet's role

Your vet may advise you to take a "wait and see" approach or suggest that they examine your mare. They may perform a rectal examination and abdominal ultrasound to examine the fetus and placenta.
Questions Your Vet Might Ask:
  • What is the appearance of the mare's udder and the area around her tail head?
  • What was the mare's breeding dates?
  • How is the mare's attitude & appetite?
  • What is the appearance of the mare's udder and the area around her tail head?
  • What are the results of the Whole Horse Exam (WHE)?

further reading & resources

Author: Doug Thal DVM Dipl. ABVP