This adult female elk stood out like a sore thumb in the rest of the elk herd but obviously she has survived despite this variation in colour, although she was slightly thinner than the rest of the herd as evident by her prominent spine.  Sometimes white discolouration of animals can be caused by parasites, disease or wounds but these problems usually only effect a small portion of the fur.  This elk didn’t appear to have any of those and therefore the most likely cause is genetic.  If you search the web there are numerous pictures of white elk and piebald deer but it appears calico or piebald elk are not that common and I have yet to see another photograph of one. Please share if you have!