I used to use Ivermectin also when I had a lot of dogs, however a word of caution. Some herding dogs, especially collies and I think border collies (but maybe some others) may be sensitive to it. Proceed with caution (and as LaRueLaDue said, speak to your Vet).
Yeah, it is some bloodlines of Collies... (My sister-in-law has Collies, and they have all sort of issues like that..) We have German Shepherd Dogs, and have never had an issue. A competent (and I stress competent) vet should be aware of these sorts of things...