Is Drontal truly time release? And in a kennel environment, would i only have to worm then twice a year, as my vet says I do? It does not seem like enough to me. I mean, dogs reinvest. I do a routine worming every month when we give ivermec (for heart worm)

Anybody have any facts/research/experience with this?

Your vet is full of BS

Dewormers treat what is there now, there is no dewormer that treats what might happen in the future. I think your vet needs to do some research into the mechanics of dewormers LOL

I think that you misunderstood your vet. He was probably talking about heartworm prevention that can be done every 6 months like the Proheart 6.

Drontal is mainly given for tape worms, while it does kill other types tapes are it's main target. Are you you sure you understood what your vet said?