does anyone know if a ddb will live with a neo if i had one of them nutered ?

most of the mastiff breeds are fairly good with other dogs anyway but i don't recommend castrating any dog unless its necessary as if you have two males living ina house then one usually has to become top dog and by castrating one of them you may be doing it to the wrong one therefore causing a non top dog siuation which usually results in endless battling between the dogs - i would introduce the two dogs on neutral territory and see how you get on from there.

I have had Tibetan Mastiffs and newfoundlands and Dogue de Bordeaux males liveing together for years with no problems