Did you know that Ft. Myer's offers vet services? It is the very basics...shots, blood tests, heart worm prevention but the prices cannot be beat. Used to be that you could schedule an appointment but now they just do "walk-ins" on certain days. We have been going for years and saving for years and the service is excellent.
Since the clinic can close for this at any time due to fulfilling their main role (looking after those special horses), it is best to call ahead. The number is 703-696-3604. Isaac who has worked there for years is wonderful.