Some people fail to understand that mares have NOT read the book. They do not care that they are supposed to go exactly 340 days. One mare I was watching went 389 - I was ready to get in there and drag that foal out… foal finally arrived, normal and healthy.
A pony mare foaled at 294 days… a healthy, normal, bouncy filly that was full term for that mare.
One mini mare I watched foaled out on day 312 three times in a row… and always between 10:30 and 11:30 at night. I wish all mares were as committed to a schedule as that one was!
Mares may bag up a month ahead of foaling - or not until as they are foaling and the milk comes down. Some get mushy butts far ahead… some don’t.
Some mares may have read Blessed Are The Brood Mares cover to cover - and dutifully wax up 48 hours ahead of foaling, go through Stage One, Stage Two… the prefect textbook delivery.
Some mares barely stop eating long enough to pop that foal out.
Some mares foal in the peace and quiet of a barn in the early hours of the morning - others prefer high noon out in the paddock with construction going on next door and landscapers on the other side of the fence with lawnmowers and weedwhackers roaring (she was completely unfazed by any of the activity).
Many years ago, the final question on my very intense Equine Reproductive Physiology course exam was what is the first rule for mares? For 50 extra points… the most predictable thing about a mare is her unpredictability. I would not be that comfortable with the way this vet is handling this mare - unless there are a few concerns that we are not aware of…