Wahl Oatmeal Essense Pet Shampoo. Pet Shampoos. Wahl Oatmeal Essense Shampoo Wahl Oatmeal Essence Shampoo is rich in the silkiest colloidal oatmeal available. This shampoo produces a thick lather that not only cleans but removes odours & leaves a vibrant & healthy looking coat. Wahl Oat.. ...