Hastings, I've used the cattle variety with the steers head on the bottle for my hounds, been using it for over 30 years. 1/10 cc for every 10# of body weight, just squirt it in the back of their mouth. Thats all Heartguard is that alot of people use for preventing heartworms, its just Ivermectin. Used to give my dogs a dose about every 2.5 -3 mths during mosquito season for heartworms, and then a couple of other times during the year for general worming.
Yes, we don't have a dog right now but I've used on every dog we've had and they never had a positive heart worm test. I cured a pup of red mange with Ivomec. I wonder if there wouldn't be some way to introduce heartworms into those pesky wolves out west. Our coyotes are kept in check by sarcoptic mange and heartworms.
