I used it for my mare, as short of putting her in a small dry lot (high energy mare, did not want to do that), or sending her off somewhere with a not much larger dry lot), I had no way of taking her off my (short, stubby Winter) pasture, nor guaranteeing fescue-free hay (even though it should be only orchard grass).
We started about 15 days out from Day 340.
She went at 365, and everything about her bag and milk progressed pretty textbook.
Because of the problem with the colostrum it causes, I had some frozen that we thawed and just gave, no questions. My vet tested the mare’s milk and it was borderline - within the normal range, but on the low side. It was just so much easier and mind-easing to know that tested high colostrum milk got into my foal, instead of waiting the 8-12 hours to find out he was low and still having to do something. And yes, of course, we still did the IgG but it would have to have been a problem with his absorption for it to have been low.
So, if you’re going to use Dom (now FDA-approved and labeled Equidone), then have colostrum to give