Liquid from teets

Question
We have a quarter horse mare that we've have for nearly 2 months-and from where we got her they said she hadn't been exposed to any stallions.  She has had 4 foals we have 2 geldings but we keep them apart by fences except for riding.  She has a liquid discharge that is almost clear (maybe a little milky) for at least a month now--is this common in a mare that has been a broodmare for a while?

Answer
Hi I have never had this happen in any of my horses unless they were close to foaling- Does she have milk? or bagged up? Did the previous owners have her for a while before you got her-if not she could have been bred by the previous owner before them- i would definitely have a vet look at her to see what is causing this. Is the discharge sticky??? Thanks- Heather