Roy, I give my dogs Ivomec (for cows and pigs)as a heartworm treatment once a month. I get it from Tractor Supply. I buy it in the injection type 50ml. bottle(1% solution) and use a 1cc syringe giving each 1/10th cc per 10# of dog. My dogs get .50cc for one and .60 for the other. I mix it with a raw egg and they lap it up. Since I started using it my dogs don't have other worms or internal parasites or fleas or ticks. In the spring we might find a tick walking on them but none attached. The problem using Ivomec for this is folks are using it for CoVid(
) so it might be hard to find. Our vet approves of using it on our dogs and it is way cheaper than heartworm meds the vets offer.
If you get it, leave the needle in the rubber top and just attach the syringe when needed. A 50ml bottle cost about $40 (before CoVid)but will last 2 or 3 years.
And, don't forget to spray your cloths with Permanone you don't get ticks either. Lyme disease is pretty prevalent up there.