I believe this is called "water belly" and is caused by kidney stones that pass into the bladder and end up plugging the bladder.  If caught before the bladder ruptures you can make a heifer out of him and all is well or you can butcher him.  Once the bladder ruptures, I'm not sure if he can be saved or not.

http://purduephil.wordpress.com/2007/04/26/cattle-feeding-urinary-calculi-or-%E2%80%9Cwater-belly%E2%80%9D/