the first place i would search is local/regional vet web sites, and see if they would consider publishing inbound links to your site.
the next thing i would recommend is purchasing SitePoint's SE Marketing Kit, which will tell you much more information about marketing your web site than you will receive on a single forum thread. i believe that was the first book i purchased from SP and found it incredible helpful with my internet marketing strategies.
p.s. we have a dog, two snakes and one bearded dragon, so we focus more on reptile specialties, which might be another angle if you plan to focus on a particular niche of pets.