I know it is cheaper to get the cattle kind of ivermectin, but dosing is also harder. When I use the liquid ivermectin, I use 1/10 cc(ml) to 10-11 lbs of body weight.

On the dandruff thing, I would check and see if the dog has lice (ewww, gross), but if they come in contact with mice, mice can carry the lice.

Also, cheap dog food with corn as the main ingredient, and lots of by-products/wheat can inflame a dog's skin and give them a skin allergy.

I own a kennel and have seen many dogs come in being fed a crappy (beneful, pedigree, ol'roy, dog chow and the likes) dog food and have problems with skin allergies and ear infections, not to mention that they constantly scratch and lick/chew their paws.

Just me $.02

DO NOT USE THE PASTE WORMERS ON DOGS!!!!

There have been several, anecdotal, I grant, references that there is an ingredient in all the paste wormers that is toxic for dogs. One that I read said that even a small amount licked up off the ground (size of a pea) can be harmful. How harmful may depends on the individual dog, but why take chances? The stuff is probably one of the so-called inert ingredients, that make the paste paste-y, but as far as I know, no-one is sure what it is right now. I think if you Google, you should get a couple of references.

I have had no trouble giving my dog the Ivomec injectable in her food, but you can also take the needle off the syringe when you draw it out, have the dog sit, open the mouth, pointing up, and squirt it to the back of the mouth, and then give a yummy treat. If your dog is difficult, try if 2 people work, or give it in food, with a tasty gravy maybe?