Flea & Tick Medicine???

calliecritturs

AgileGSD

 The companies weren't all that great about getting the truth out either - Heartgard even used Lassie as "spokesdog"

That's my point -- they didn't want to lose a chunk of business so they have dosed the product SO low (so it doesn't react in the breeds that are sensitive) that it fails regularly -- in many places in the South they are seeing heartworm **resistant** to ivermectin because so many have survive the ultra low dose that it's begun to create a version of super heartworm. 

Because collies and shelties and the various herding breeds that are sensitive to ivermectin are so often cross-bred with other breeds it's pretty difficult to refer to all those breeds.  Simply saying ""ok for herding dogs" is just a more generic term.  I do occasionally TRY to be brief.

 

I've heard that approximately 70% of Collies and up to 50% of Aussies have the mutant MDR1 gene, so cross bred dogs might well have a relatively high chance of having it in some areas of the country where herders are prevalent.  Thanks for pointing that out.  And, it's not just ivermectin that's a problem.  There's a whole list of drugs that affected dogs should avoid.