I have a new horse that's 6 years old now and he
burps when he has an upset stomach. Last summer I put him out on some tall green
grass for 15 minutes and it happened right after that. I have never seen a horse
burp either, I didn't think they could. But because he was acting a little
colicky also I rushed him to the vet. Of course the trailer ride over there
cured him and by time we got there he jumped out of the trailer looking
perfectly normal. The vet I went to said they've never heard a horse burp
either. At least with this horse I now have a very clear sign of when he's got
stomach problems.