I would never contradict you on any dog issue, but heartworm prevention is dependent on geography, among other things.
My sister is a mega-dog lover and has several, along with numerous other animals. She and her husband own a horse farm in central Florida.
Where she lives, it's not a question of if a dog gets heartworms; it's when. All untreated dogs who spend even minimal time outdoors get heartworms sooner or later, and it's usually sooner. She treats all of her dogs year round.
Where I live (Kentucky), heartworms are somewhat common, but a dog that spends most of its time indoors may be able to forego heartworm treatment. My dog spends a fair amount of time outdoors and I live near a creek, so I give her a preventive during the warm weather months but not in the winter. Heartworms, as I'm sure you know but others may not, are mosquito borne.
BTW, ivermectin should never be given to collies. I don't know why, but my vet confirmed that. I don't know if that includes Border Collies--which is what I have--but to play it safe, I don't give it to my dog.
BTW, heartworm preventives work backwards, not forwards. They get rid of any heartworms the dog may have picked up over the last 30 days or so., but will not prevent the dog from picking up the parasite in the month going forwards.
That's my understanding of the issue, anyway.
I wish they had not screwed up the formula of Sentinel or I’d agree with you completely.
The vet switched them to Heartgard and then Iverheart and both of them make my dogs sick and none of them are anything like collies...:(
What good are the pills if they just throw them up a half hour later?
The one who *did* keep her pill down was feverish and sick for 2 days, after.
Rather than poison my dogs with the new ‘extra bonus’ flea junk every month, I’ve had to resort to other measures.
Maybe they’ll go back to their original formulation, someday.
This just sucks.
The other thing I forgot to mention was whipworms.
Neither pill touches them in the Ivermectin dosage of the pills and they are a far greater danger than heartworms, here.
Again, it all sucks.