*waves hands in the air* OOH! ME! I'm a Ross student! So, I'm only a first semester, but I also know people in upper semesters and whatnot, and I live down here, so I think I've got a pretty good idea of what's going on.
First of all, I'm also not a fan of PETA- they tend to blow things out of proportion and give "animal rights" a bad name. The things they say on that site are just ridiculous, and they don't happen here. Our professors here yell at us if we're too rough with palpating animals, so to think that they would tell us to hack up a live donkey is almost laughable.
I don't know about terminal surgeries here, but as optimistic 13 said, dogs that are euthanized in shelters die much more needlessly than a dog that is used for educational purposes in a vet school. I'm pretty sure they don't do unnecessary surgeries on healthy animals here, but I would have to check.
Right now, in first semester, we're dissecting a dog in anatomy lab. I don't know for sure, but we think she died because of heartworms (her heart was full of them- it was neat to look at). We share a dog between 6 people, so we're not using more dogs than is necessary. While it saddens me that this dog died (of course), I think it would be even worse for me to never have seen the inside of a dog when I do my first surgery.
Basically, I think you should take what PETA says with a grain of salt. The accusations on that website are crazy, and I think their info may be outdated. I don't know what went on before I got here, but I know that my class was one of the first classes to start after they changed the curriculum around a bit. I don't know if these practices did exist before and getting rid of them was part of the curriculum change, or if they never existed in the first place. But I don't think I'd be here if something like that was going on.
If you have any other questions about Ross, let me know or PM me. I'd be happy to help.