Ask HN: How would one get a list of all veterinarians in the US?

Hi HN,

I have a great idea that will revolutionize veterinarian care, but I would need to get a list of vets in the U.S. who would be willing to get a referral from my website. I get about 10 emails a month that could be monetized with a referral fee, but I need to create a list of vets that are available and willing. How would you go about contacting generating a list of vets in the U.S., and not spamming them with email that they would never read?