Toch nog even een tip neerzetten, misschien kan dit voor anderen ooit ook nog practisch zijn, sorry wel in het engels
What I've found best is to introduce the mare and foal slowly in a very controlled environment. Make sure the barn is quiet and you have no spectators. You just need someone to hold the mare and someone to hold the foal. I'll generally bond mare and foal in many frequent sessions-- we will keep the mare and foal in separate stalls (preferably where they can see each other), then ever couple hours bring the foal in for a short bonding session. I'll never force the foal to nurse if both mare and foal aren't ready yet. Instead, I'll bring the foal into the mare's stall, let them sniff each other, then if the mare doesn't seem aggressive, I'll coax the foal in the direction of her flank. If the mare is being tolerable, this is a great time to feed the foal out of his bottle or bucket so he starts associating the mare's flank region with food.
How many times you will need to do this really depends on the mare and foal. If the foal is searching and seems to know he's supposed to nurse, and the mare is being cooperative, you may be able to get him on the first time. If he's acting a bit dumb, you may need many sessions to "reintroduce" him to what an udder is, but coaxing him underneath, squirting a little milk out so he can get a taste, etc. If the foal seems to know what to do, but the mare is aggressive or afraid, you will need to spend time desensitizing and let her get used to you and the foal touching her sides, her legs, her udder, and belly. Just make sure you never, ever get the foal kicked.
I don't like to leave mare and foal unsupervised together in the stall until they are at the point where I can bring the foal to the mare's stall and let him in with the mare loose in the stall, and he'll go straight to nursing without any negative reaction from the mare. Even at this point, we keep a close eye on them until we are sure the mare won't step on him, lay on him, etc.
Wow, I've written a novel. Hopefully I've written something useful and am not just rehashing what you already know. Good luck, and just remember, not all mares and foals bond. There's nothing wrong with raising a bucket baby!