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Ask the Vet: Is Horse Dewormer Safe for Dogs?

Posted on: September 20, 2011 by Dr. Lydia Gray

I was told by a Jack Russell Terrier breeder that it would be ok to give my Jack Russel Terrier Liqui-Care P. for worms. I know this stuff is for horses. Is this ok or not? Thank you!
– CO, Michigan

Dear CO,

If you’re a fan of my Ask the Vet blog, then you know I’M not a fan of giving dogs products made for horses and vice versa. So the short answer to your question is: no, giving your Jack Russell a horse dewormer is NOT okay.

The long answer is that horse dewormers are way more concentrated than dog dewormers. The product you specifically mentioned, Liqui-Care P, is designed to be given at a rate of 6ml per every 100lbs body weight. For a 1,000 pound horse, that’s 60mls, easily doable with a large syringe. But for a 10lb Jack Russell, that’s only 0.6ml, a small amount to have to be sure to measure correctly. And since this particular dewormer is a suspension—meaning it has to be shaken or stirred first because it has a tendency to separate—you have to be that much more careful when it comes to measuring.

My advice is to stick with a product specifically made for dogs and puppies. Most of the canine dewormers that contain the same active ingredient—pyrantel pamoate—are designed to be given at a rate of 5ml (one full teaspoon) per every 10lbs of body weight, a convenient amount to give to a small dog.

One other thing to think about: since pyrantel pamoate controls the roundworms Toxocara and Toxascaris and as well as the hookworms Ancylostoma and Uncinaria, why not use a heartworm preventative like HeartGard Plus which not only controls these parasites but also heartworm, a much more deadly threat?