Dogs can get all sorts of bug bites. If he had that many ticks on him and was not on preventative you would have noticed while bathing him. Tick bites tend to have a hard red lump for a few weeks.
Even if you tested your dog the same day, testing positive for most tests does not tell whether there is active infection or not. For that you have to send a different test out to a lab. There is no reason to automatically treat a dog who may never have an active infection.
The lyme vaccine has about a 60% efficacy rate and must be boostered every 6-12 months to be effective. Using a tick preventative is often a better bet. The lyme vaccine does not prevent against other tick borne diseases.
Even if you tested your dog the same day, testing positive for most tests does not tell whether there is active infection or not. For that you have to send a different test out to a lab. There is no reason to automatically treat a dog who may never have an active infection.
The lyme vaccine has about a 60% efficacy rate and must be boostered every 6-12 months to be effective. Using a tick preventative is often a better bet. The lyme vaccine does not prevent against other tick borne diseases.