Pretty much all the dogs I know will barf horse hoof trimmings back after eating them.
The odd thing is dogs don’t seem to barf up after gnawing on cow hooves from the pet supply store!
I never use the rawhide or pig ears for treats now, since they get soft with chewing. Dogs can gnaw off pieces to swallow whole, clogging their digestive system. This will require surgery to remove!!
My dogs have strong jaws and muscles so they require gnawing items that don’t soften up to swallow or break apart after long times of being chewed on. My Aunt suggested the plain cow hooves since they worked so well for her GSD with the big teeth and jaw.
I have been really happy using the plain cow hooves as dog chewing toys here. A hoof lasts about a week with lots of attention from the dog. I toss the hoof when it gets small enough to fit all the way in their mouth to accidently swallow.
Hoof seems to just shrink away, so pieces coming off are quite tiny to easy to swallow. Never a choking hazard. Maybe whatever they clean the hooves with in processing, removes the dirt making dogs barf after eating “fresh” hooves. Dogs here, do not barf with the cow hooves.
I DO NOT recommend the filled cow hooves, they seem to make dogs have gas.
You might want to ask the Vet how many surgeries they do to find rawhide or leathery pig ears causing the problem. You never know WHICH of thse kind of treats will cause a problem for your pet until it happens.