You need a PharmD, not a DVM to be a pharmacologist for animals.
BUT be aware that there are very few vet-specific jobs out there. Unless you work at a teaching hospital or a veterinary compounding pharmacy (or in research), you would probably end up working with people for most of your job.
Most meds used for animals are also used for humans or are very similar. Add that to the fact that almost all vet clinics dispense their own meds, and there aren't too many jobs for vet-specific PharmD's.
You're welcome to come ask on the pre-vet forum (you're not allowed to cross post but you could ask a mod to move your thread)... you might get more answers from vets and vet students that way.
Edit: I don't want to make it sound like you can just give your medications to your pets... very bad idea. Just meant that the actual drugs we use on animals are usually from the same drug classes as those used for humans.