How to gain experience when I don't have any?

I'm in my 4th year of college (at UCSD) and want to be a veterinarian (I decided kind of recently) so I've been going through the phonebook calling every vet office in the area trying to get any sort of job, either volunteer, paid, or just observing, but they all told me no. I have a bunch of friends who are pre med and they all have jobs working in hospitals, observing and doing miscellaneous things. Why can't I get a job like that? My grades are good, I have a 3.7, I've had other paid and volunteer jobs (not related to animals), and I'm currently volunteering for an animal center "socializing" abandoned dogs. Vet school requires a minimum of 180 hours experience, and I don't think socializing dogs is the kind of experience they are looking for. How do I get real experience?? Any ideas??