I learned about this shampoo almost 2 decades ago when I got my first Australian Shepherd, a black tricolor male with 4 white paws, a blaze and a big, thick white collar...that seemed to always retain the pink-orange stain of our Georgia red clay even after a bath. Friends of mine who had both horses and Aussies, showed me how to use Quic Silver as a dog shampoo, and WOW, I was stunned at the difference this made! No more pink feet! No orange chest staining! And the black and copper parts were equally shiny and practically sparkled once my dog was dry. Follow the directions on the bottle, and don’t leave the shampoo on your dog longer than recommended, or you might get a bit of blue purple staining in the light parts (it will wash out next time - I know because I made that mistake just once). With a working Aussie that also shows in conformation shows - sometimes one right after the other - it was important to find a product that could clean out all the farm mud so he could at least start the weekend out with a sparkling, shiny coat. Not sure if it would work for breeds with coats different than Aussies (double coat, with outer fairly harsh), but for my herding dog, this is the best stuff to keep him looking like a conformation champion, even if he did just come out of the cattle arena.
This is the best product for shampooing a gray or white horse. Or horses like paints or those with lots of chrome. This gets the whites blindingly white and I have never found another product that does it as well. Your white horse will be a unicorn! I won't be without this.