In Dogmeat's dialogue, there are 'Scold' and 'Praise' options.The Puppies! perk has a second, unintended use that makes it possible to recruit multiple followers.At level 22 (with the Broken Steel add-on installed), the Puppies! perk can be taken so that when Dogmeat dies, a puppy appears at the main door of Vault 101.He may be found in the area around Vault 101 in this scenario.
Regardless of any other companion or Karma level, Dogmeat can be recruited without incident. He may also be found fighting super mutants in a random place at The Mall.