Week old foal bagged up and streaming milk

I’m trying to Google some info, but I keep hitting only info about mares and lactation… I have a week old foal who is bagged up and STREAMING milk. This is a first for me, so I’m curious if it’s like human babies? Just a hormonal thing that will resolve as hormones etc settle?
Have a call in to my vet as well of course.
Thanks for any further info!
EDITED TO SAY - there is nothing out there in the pasture (that I’m aware of) that is excessive in any phytoestrogens etc for dietary cause

Has the mare had anything (medication wise) that she could be passing on to the foal through her milk? Soy? I’m stumped. I’ve googled and googled. It will be interesting to find out what your vet thinks.

Interesting. Never heard of this.

Mats H.T. Troedsson, … Karen McDowell, in Large Animal Internal Medicine (Sixth Edition), 2020

Galactorrhea and Precocious Mammary Gland Development

Galactorrhea, the abnormal manifestation of lactation (not the secretion of true milk), occurs occasionally from the primordial mammary gland of young foals and ruminants, including neonates.250 The secretion is popularly known as witch’s milk.


Witches’ Milk

Sorry for Wikipedia as source, but it covers both the physiology & the fun “cultural interpretations”


Apparently it’s not an issue. That’s a relief!
Who knew? Not I.

It happens with human babies, too. Male and female!

Sorry banmharcach! I was so excited that I knew why, I missed your post.