Cross-post question for experienced breeders with older mares
This question actually came from a TB board, where a breeder with an older mare wants to know whether any breeders have experience with an older mare with minor vaginal bleeding (she has been checked by his vet and they suspect a varicose vein).
Varicose vein rupture is a relatively common problem in mares and manifests as vaginal bleeding. As the fetus becomes larger, more weight and strain is placed on the vaginal vault and subsequently, some of those varicose veins will rupture. It is not just older mares that will occasionally have the problem, either. And, the amount of blood can sometimes be alarming!
FWIW, vaginal bleeding is rarely a precursor to a mare aborting. If the mare has no other issues - no fever, no colic like behavior, no sweating, no udder enlargement/milk production, etc. - chances are it is nothing to worry about.
I had a mare in her 20s who had a couple of varicose veins that would periodically bleed when she was pregnant. My vet used a laser to cauterize them. She was in foal at the time and the whole procedure was very uneventful. It completely stopped the bleeding.
Minglewood Sport Horses
Ballston Spa, NY