My best friend is well leaving a job where he worked at a compounding pharmacy that dealt directly with Vet. Medicine. He never took a class on vet pharm. beforehand so it was a large learning curve but yet he enjoyed it very much, just not the management.
I interned at the UC Davis vet pharmacy, supposedly the best vet program in the nation, before entering pharm school. All I can say is its totally different from your typical retail pharmacist. They told me its extremely hard to get a job as a vet pharmacist and even if you do, the salary is not appealing. But hey, if you like animals, its worth it.