Not sure if this will help. My 12 year old mare had milk problems, I believe from the heat. That isn't your problem butttt..
The foal was about 2 weeks old. I would make the milk replacer and put it into a deep tuperware bowl. With a little coaxing(used my finger) I lead him to the bowl. He immediatley started to drink. He would not drink from a bottle.
My other mare this year wouldn't be nice to her foal but after some pain meds and some pumping finally started being a mother and has been a terrific one ever since.
Question, can you give those natural calmers to like sedate the mare????? I am sure Banamine would be much more effective but a good question.
Good Luck and keep us posted.
Traci