JFTDWS
+++ Out of Cheese Error +++
What do you mean responsible breeding? If the OP is to be believed (and I'm not going to think otherwise because I have to go on 'face value') she/he intends to keep the foal. There are far more instances of irresponsible breeding - namely stallions over here in with herds of mares popping out foals every year. Connemara foals (decent breeding) are going for next to nothing at the moment. At least the OP did a bit of research. You can put the best of two types together and still get a donkey anyway.
I mean breeding from a highly unsuitable mare. The idea of a vet breeding from anything with an AI disease astounds me. Just because there's worse going on out there doesn't make it ok.