A Florida veterinary company, ShotVet, is partnering with Walgreens to offer lower-cost, walk-up clinics for dogs and cats in the parking lots of about 50 of the drugstore chain’s Massachusetts stores. ShotVet will visit each participating Walgreens for an hour each month with a vet, technician and “client educator.” But the Massachusetts Veterinary Medical Association doesn't like it. State law requires a “veterinary-client patient relationship” be established before any vaccination is given,