I have had this befor. It is some times genetic I hear. There are also some hormones that are given to cattle at a young age that warn that when given can cause nipple elongation and to become larger. To answer what would I do. You can take a needle made for this and drain the milk to allow the calf to nurse. Next let the calf nurse and keep the cow off of any thing that is rich, like cubes. Just feed her some tough hay. When the calf gets bigger you can sale 2 instead of just one. Pain in the butt yes. Worth the time if she is calm. If she is a mean one I would sale her. No matter what the previous post to you were right, she needs to go to the sale barn. I guesse the real question is, how much time do you want to spend? Hope this helps.