James Peden, author of Vegetarian Cats and Dogs states there are natural urinary acidifiers, including asparagus, peas, brown rice, oats, lentils, garbanzos, corn, Brussels sprouts, lamb's quarters (the herb Chenopodium album, also known as pigweed), most nuts (except almonds and coconut), grains (not millet), and wheat gluten (used in kibble recipes). (veganoutreach.org)
Then, poof, a strain of pigweed showed up that Roundup would not kill. (religion.blogs.cnn.com)