I think like most things the "bare minimum" is not enough, especially when its very competative. My PhD program has a vet students that are in the DVM/PhD program as well, not to mention pre-Vets who want to get into vet school after their MS or PhD, and time and time again they've stated that course work was a big thing, followed by vet experience in getting them into our vet program. Nobody really said anything about GRE scores.
Students that are applying after undergrad, most were of some sort of animal science, rather than your vanilla biology. Students that got in after reapplying more than likely have a masters degree, since our program recommends re-applicants to do that (hence students in my grad program). Older students in the class tend to already have graduate degrees. In the second year class, a few of the students have PhD's already. Without know what your undergrad classes, it would be hard to say, but if it is not a science program, then it may be very difficult to compete with students who have spent their lives, literally doing additional degrees, and vet work experience to get in. I have to give kudos to them...since I've been fortunate to experience their pharmacology course, and it is just as rigorous (if not more) than the med school stuff.
As for these schools using the GRE rather than MCAT. I can't speak for other schools, but only for UCD. They originally accepted the VCAT, their own special test way back in 2000 or so. But apparently it became obsolete in the last few years so the GRE was sufficient. The vet students usually say their undergrad/grad grades played a bigger role, as their animal science courses were a better indicator of how well they'll do in vet school. But the real reason, I don't know, should ask someone in the vet forums. On that note, I suggest you call up these schools and tell them of your situation. I know our vet school will rank applicants, and will provide feedback on where you're at, what you can do, etc.
