what's the 6 month heartworm shot ?
It's called ProHeart.
https://online.zoetis.com/us/en/products/pages/proheart6_product_education.aspxI've heard a lot of folks go this route and be just fine, BUT, having worked in the vet med field when this shot came out, I got to hear a lot of negatives on it, so I never tried it. I just use Ivomec oral every month.