My mom is giving milkthistle to her senior dog based on her conventional vets recommendation. Her dog is of a breed prone to skin problems and the prednisone had created liver problems. The milk thistle is helping a lot.
I use a holistic vet for my pets. He recommended I give a quarter tablet of Rainbow Light's Milk Thistle formula to my cat when she got poisoned from the landscaping chemicals. My cat is an indoor cat. I take her for walks outdoors on a leash from time to time. I have no control over what chemicals are used in the commercial landscaping, so I have to keep her from exploring the shrubs on our walks. The milk thistle helped her very quickly.
Dr. McCall may be able to find a holistic vet in your area to help with your dog. He's a great vet whose been in practice a long, long time. Long enough to see animals from birth, through their entire lifespan. He knows what really works and what is a "fad" in popular practice.
The key is to stay away from conventional dog foods. Even some of the brands sold by veterinarians have by products and other garbage in them. Dr. McCall had recommended Flint River Ranch dog and cat foods to me if I wanted to feed a kibble type product. They have a lot of distributors so I'm posting the corporate site here. You can download the brochures and other info from the site. http://www.flintriver-home.com/ingredients.htm