Originally Posted by tealamutt
Was it just one noise that you heard? Could you see his abdomen contracting? Thumps are almost always due to underlying conditions (unlike human hiccups) such as dehydration and/or electrolyte imbalances. I would call a vet if you are certain that it is thumps and not just a hiccup or two, which I have also seen horses get, because whatever is causing them needs to be treated.
It was one noise, but I heard it several times in a row, it would stop, and then I'd hear it again. I didn't hear anything for awhile, so I hopped on him, and didn't hear it for the rest of the time I was there. From what it sounded like to me he wasn't active enough to have the imbalance or the low blood calcium, but I'm not sure. I don't remember his abdomen contracting, but I was a little floored by the noises coming from him. I guess it would be good to call the vet if I hear it again tomorrow?