Well, I have it on excellent authority that horse poo, while not as aromatic, has a more robust flavor with a nutty, full-bodied quality that improves with age ... at least, that's what the RIRs told me ....
My mom told me once that there was a hippy lady that lived down the road from their cow farm where she grew up. Her name was Meta Earthling and she would come down and get cow poo that she added to her homemade, "herbal" shampoo.... I think it had mayo in it also, you should definately give it a try! They mayo may add some tang.