I've never been in a vet school interview, but for Ohio State at least, I've been to multiple "mock interviews" that the vet school faculty gives to students.
What I have gleaned is that they don't always care that you answer questions completely "right," they (or at least one of the perennial interviewers) want people they can talk to easily - people who are polite, polished, and appear confident.
Seriously, I've heard stories of people missing really important questions and still getting in, like some guy didn't know what BSE is.... which to me would be very unforgivable, considering the huge impact that disease has had on public health, food safety, food processing laws, etc. (I'm also a public health person so I clearly have a bias).