Bullshit, or cow manure, is a valuable fertilizer for your vegetable garden or farm, especially if you are into organic gardening and thus can't use synthetics. You can also mix it with the grass clippings and apple cores in your compost pile -- the anaerobic bacteria do good for the process of decay, which turns your garbage into good soil. As the Discordians put it: "Bullshit makes the flowers grow ... and that's beautiful."
Guano -- the nitrogen-rich shit of bats and some birds -- was once mined from caves in Puerto Rico and other island locations. (You may recall the importance of guano mining in the plot of Ian Fleming's Doctor No.) Before the advent of synthetic fertilizer, the guano trade was an important source of fertilizer for farming.
Nature, by and large, does not waste anything, even the things that we refer to as "waste". When life gives you shit, make fertilizer!