I used to buy it from Tractor Supply for my dogs. It was made for sheep, but its the same stuff. In that particular concentration, 0.1 CC per dog, once per month. With 4 dogs, it lasted me years.
I recently ran out, and tried something different, I got the apple flavored version made for horses. Diluted it with peanut butter, now its 0.1 grams per dog per month, should last me a long while.
I wonder if there will be a run on this stuff....
Get the liquid from Tractor Supply as well. I use the same dosage. Also a couple times a year will go up to .6mg/kg but not over. I tested my dogs for the genetic sensibility before giving it at these levels.
(Ivermectin should not be given to Collies or Shelties or any breed related to them at dosages above what Heartgard has.)