I have definitely heard horses belch. I realise horses can't vomit but burping is actually a different mechanism. In humans, the act of vomiting is quite complex and involves a coordination of various internal muscles while I suspect burping is more of a passive process. Therefore, just because horses can't vomit (not sure exactly why, probably due to their anatomy.. somehow) I don't see why they couldn't burp.
I found this:
It is generally accepted that horses don't belch because the cardiac sphincter (the valve between the stomach and esophagus) only allows one-way flow. Because of this, most horses will have gastric rupture when the stomach is distended because they cannot eructate (vomit or belch). That being said, most veterinarians would recognize that this is not always true. Some horses will "belch." Others with gastrointestinal problems preventing fluid from getting out of the stomach through the small intestine will spontaneously reflux. The jump to gastric ulcers is a bit of a leap for me. At this time it sounds like your horse has a pretty relaxed lifestyle, including pasture and not a large workload. I am wondering if your horse is cribbing or windsucking. Some horses will crib on physical structures, while others will simply clench their teeth and flex at the poll to do it. I don't think it will hurt to have a gastroscopy done, but maybe you can have your veterinarian observe the horse, also.
I think that if they can Fart they can burp,And I know a horse can fart I was at the wrong end on it when it happened !!
Shiloh doesn't crib or wind suck, she's only 2. I notice it when she has just eaten her pellets and comes up to get a drink. When she is done there is an escaping of air not a major BLARPPP kind of belch but more of a dainty girly "oh excuse me" burp.
lol..trust me I KNOW for a FACT! That horses can fart.lol. But im not too sure about the burping.i mean I always hear those tummies making noises.and they are really loud.but im not sure if they ever really come out.at least outta the front end.im curiouse too! I know some horses that make grouling sounds though.like when they breathe sometimes..idk why?
Lmao...we call it crop dusting!(horsey farts) my eyes are teary im laughin so hard!!!!!